MDEV-29694 Remove the InnoDB change buffer

The purpose of the change buffer was to reduce random disk access,
which could be useful on rotational storage, but maybe less so on
solid-state storage.
When we wished to
(1) insert a record into a non-unique secondary index,
(2) delete-mark a secondary index record,
(3) delete a secondary index record as part of purge (but not ROLLBACK),
and the B-tree leaf page where the record belongs to is not in the buffer
pool, we inserted a record into the change buffer B-tree, indexed by
the page identifier. When the page was eventually read into the buffer
pool, we looked up the change buffer B-tree for any modifications to the
page, applied these upon the completion of the read operation. This
was called the insert buffer merge.

We remove the change buffer, because it has been the source of
various hard-to-reproduce corruption bugs, including those fixed in
commit 5b9ee8d8193a8c7a8ebdd35eedcadc3ae78e7fc1 and
commit 165564d3c33ae3d677d70644a83afcb744bdbf65 but not limited to them.

A downgrade will fail with a clear message starting with
commit db14eb16f9977453467ec4765f481bb2f71814ba (MDEV-30106).

buf_page_t::state: Merge IBUF_EXIST to UNFIXED and
WRITE_FIX_IBUF to WRITE_FIX.

buf_pool_t::watch[]: Remove.

trx_t: Move isolation_level, check_foreigns, check_unique_secondary,
bulk_insert into the same bit-field. The only purpose of
trx_t::check_unique_secondary is to enable bulk insert into an
empty table. It no longer enables insert buffering for UNIQUE INDEX.

btr_cur_t::thr: Remove. This field was originally needed for change
buffering. Later, its use was extended to cover SPATIAL INDEX.
Much of the time, rtr_info::thr holds this field. When it does not,
we will add parameters to SPATIAL INDEX specific functions.

ibuf_upgrade_needed(): Check if the change buffer needs to be updated.

ibuf_upgrade(): Merge and upgrade the change buffer after all redo log
has been applied. Free any pages consumed by the change buffer, and
zero out the change buffer root page to mark the upgrade completed,
and to prevent a downgrade to an earlier version.

dict_load_tablespaces(): Renamed from
dict_check_tablespaces_and_store_max_id(). This needs to be invoked
before ibuf_upgrade().

btr_cur_open_at_rnd_pos(): Specialize for use in persistent statistics.
The change buffer merge does not need this function anymore.

btr_page_alloc(): Renamed from btr_page_alloc_low(). We no longer
allocate any change buffer pages.

btr_cur_open_at_rnd_pos(): Specialize for use in persistent statistics.
The change buffer merge does not need this function anymore.

row_search_index_entry(), btr_lift_page_up(): Add a parameter thr
for the SPATIAL INDEX case.

rtr_page_split_and_insert(): Specialized from btr_page_split_and_insert().

rtr_root_raise_and_insert(): Specialized from btr_root_raise_and_insert().

Note: The support for upgrading from the MySQL 3.23 or MySQL 4.0
change buffer format that predates the MySQL 4.1 introduction of
the option innodb_file_per_table was removed in MySQL 5.6.5
as part of mysql/mysql-server@69b6241a79876ae98bb0c9dce7c8d8799d6ad273
and MariaDB 10.0.11 as part of 1d0f70c2f894b27e98773a282871d32802f67964.

In the tests innodb.log_upgrade and innodb.log_corruption, we create
valid (upgraded) change buffer pages.

Tested by: Matthias Leich

122 files changed, 1636 insertions, 9273 deletions

diff --git a/extra/mariabackup/xtrabackup.cc b/extra/mariabackup/xtrabackup.cc
index 27bb10bf82e..9d86ae100af 100644
--- a/extra/mariabackup/xtrabackup.cc
+++ b/extra/mariabackup/xtrabackup.cc
@@ -2169,12 +2169,6 @@ static bool innodb_init_param()
 
 	srv_print_verbose_log = verbose ? 2 : 1;
 
-	/* Store the default charset-collation number of this MySQL
-	installation */
-
-	/* We cannot treat characterset here for now!! */
-	data_mysql_default_charset_coll = (ulint)default_charset_info->number;
-
 	ut_ad(DATA_MYSQL_BINARY_CHARSET_COLL == my_charset_bin.number);
 
 #ifdef _WIN32
diff --git a/mysql-test/suite/encryption/t/innodb-redo-badkey.opt b/mysql-test/suite/encryption/t/innodb-redo-badkey.opt
index 2de0bdb3241..60d43648e00 100644
--- a/mysql-test/suite/encryption/t/innodb-redo-badkey.opt
+++ b/mysql-test/suite/encryption/t/innodb-redo-badkey.opt
@@ -1,4 +1,3 @@
---innodb-change-buffering=all
 --innodb-encrypt-tables=on
 --innodb-tablespaces-encryption
 --innodb-encryption-threads=2
diff --git a/mysql-test/suite/encryption/t/innodb-redo-nokeys.opt b/mysql-test/suite/encryption/t/innodb-redo-nokeys.opt
index 6190ad24ed3..4e7b22902a4 100644
--- a/mysql-test/suite/encryption/t/innodb-redo-nokeys.opt
+++ b/mysql-test/suite/encryption/t/innodb-redo-nokeys.opt
@@ -1,2 +1 @@
---innodb-change-buffering=none
 --innodb-default-encryption-key-id=20
diff --git a/mysql-test/suite/innodb/r/ibuf_delete.result b/mysql-test/suite/innodb/r/ibuf_delete.result
deleted file mode 100644
index 7423d3cfa3e..00000000000
--- a/mysql-test/suite/innodb/r/ibuf_delete.result
+++ /dev/null
@@ -1,53 +0,0 @@
-SET @buffering= @@innodb_change_buffering;
-SET GLOBAL innodb_change_buffering= deletes;
-Warnings:
-Warning	1287	'@@innodb_change_buffering' is deprecated and will be removed in a future release
-SET @flush= @@innodb_flush_log_at_trx_commit;
-SET GLOBAL innodb_flush_log_at_trx_commit= 0;
-CREATE TABLE t1 (
-a varchar(1024),
-b varchar(1024),
-c varchar(1024),
-d varchar(1024),
-e varchar(1024),
-f varchar(1024),
-g varchar(1024),
-h varchar(1024),
-key (a),
-key (b),
-key (c),
-key (d)
-) ENGINE=InnoDB;
-INSERT INTO t1
-SELECT REPEAT('x',10), REPEAT('x',13), REPEAT('x',427), REPEAT('x',244),
-REPEAT('x',9), REPEAT('x',112), REPEAT('x',814), REPEAT('x',633)
-FROM seq_1_to_1024;
-CREATE TEMPORARY TABLE t2 (
-a varchar(1024),
-b varchar(1024),
-c varchar(1024),
-d varchar(1024),
-e varchar(1024),
-f varchar(1024),
-g varchar(1024),
-h varchar(1024),
-i varchar(1024),
-j varchar(1024),
-k varchar(1024),
-l varchar(1024),
-m varchar(1024),
-key (a),
-key (b),
-key (c),
-key (d),
-key (e),
-key (f)
-) ENGINE=InnoDB;
-SET @x=REPEAT('x',512);
-INSERT INTO t2 SELECT @x, @x, @x, @x, @x, @x, @x, @x, @x, @x, @x, @x, @x
-FROM seq_1_to_768;
-DROP TABLE t1, t2;
-SET GLOBAL innodb_change_buffering= @buffering;
-Warnings:
-Warning	1287	'@@innodb_change_buffering' is deprecated and will be removed in a future release
-SET GLOBAL innodb_flush_log_at_trx_commit= @flush;
diff --git a/mysql-test/suite/innodb/r/ibuf_not_empty.result b/mysql-test/suite/innodb/r/ibuf_not_empty.result
deleted file mode 100644
index 1dc7f0324d3..00000000000
--- a/mysql-test/suite/innodb/r/ibuf_not_empty.result
+++ /dev/null
@@ -1,20 +0,0 @@
-CREATE TABLE t1(
-a INT AUTO_INCREMENT PRIMARY KEY,
-b CHAR(1),
-c INT,
-INDEX(b))
-ENGINE=InnoDB STATS_PERSISTENT=0;
-SET GLOBAL innodb_change_buffering_debug = 1;
-SET GLOBAL innodb_change_buffering=all;
-Warnings:
-Warning	1287	'@@innodb_change_buffering' is deprecated and will be removed in a future release
-INSERT INTO t1 SELECT 0,'x',1 FROM seq_1_to_1024;
-# restart: --innodb-force-recovery=6 --innodb-change-buffer-dump
-check table t1;
-Table	Op	Msg_type	Msg_text
-test.t1	check	Warning	InnoDB: Index 'b' contains 990 entries, should be 1024.
-test.t1	check	error	Corrupt
-# restart: --innodb-force_recovery=0
-SET GLOBAL innodb_fast_shutdown=0;
-# restart: --innodb-force_recovery=0
-DROP TABLE t1;
diff --git a/mysql-test/suite/innodb/r/innodb-change-buffer-recovery.result b/mysql-test/suite/innodb/r/innodb-change-buffer-recovery.result
deleted file mode 100644
index 42fdf680f2e..00000000000
--- a/mysql-test/suite/innodb/r/innodb-change-buffer-recovery.result
+++ /dev/null
@@ -1,51 +0,0 @@
-#
-# Bug#69122 - INNODB DOESN'T REDO-LOG INSERT BUFFER MERGE
-#             OPERATION IF IT IS DONE IN-PLACE
-#
-call mtr.add_suppression("InnoDB: innodb_read_only prevents crash recovery");
-call mtr.add_suppression("Plugin initialization aborted at srv0start\\.cc");
-call mtr.add_suppression("Plugin 'InnoDB'");
-FLUSH TABLES;
-CREATE TABLE t1(
-a INT AUTO_INCREMENT PRIMARY KEY,
-b CHAR(1),
-c INT,
-INDEX(b))
-ENGINE=InnoDB STATS_PERSISTENT=0;
-SET GLOBAL innodb_change_buffering_debug = 1;
-SET GLOBAL innodb_change_buffering = all;
-Warnings:
-Warning	1287	'@@innodb_change_buffering' is deprecated and will be removed in a future release
-INSERT INTO t1 SELECT 0,'x',1 FROM seq_1_to_8192;
-BEGIN;
-SELECT b FROM t1 LIMIT 3;
-b
-x
-x
-x
-connect  con1,localhost,root,,;
-BEGIN;
-DELETE FROM t1 WHERE a=1;
-INSERT INTO t1 VALUES(1,'X',1);
-SET DEBUG_DBUG='+d,crash_after_log_ibuf_upd_inplace';
-SELECT b FROM t1 LIMIT 3;
-ERROR HY000: Lost connection to server during query
-disconnect con1;
-connection default;
-FOUND 1 /Wrote log record for ibuf update in place operation/ in mysqld.1.err
-# restart: --innodb-read-only
-CHECK TABLE t1;
-Table	Op	Msg_type	Msg_text
-test.t1	check	Error	Unknown storage engine 'InnoDB'
-test.t1	check	error	Corrupt
-FOUND 1 /innodb_read_only prevents crash recovery/ in mysqld.1.err
-# restart: --innodb-force-recovery=5 --debug-dbug=d,crash_after_log_ibuf_upd_inplace
-SELECT * FROM t1 LIMIT 1;
-a	b	c
-1	X	1
-SET GLOBAL innodb_fast_shutdown=0;
-# restart
-CHECK TABLE t1;
-Table	Op	Msg_type	Msg_text
-test.t1	check	status	OK
-DROP TABLE t1;
diff --git a/mysql-test/suite/innodb/r/innodb-wl5522-debug.result b/mysql-test/suite/innodb/r/innodb-wl5522-debug.result
index ff0f8b2acc8..1c3b10c0597 100644
--- a/mysql-test/suite/innodb/r/innodb-wl5522-debug.result
+++ b/mysql-test/suite/innodb/r/innodb-wl5522-debug.result
@@ -454,11 +454,6 @@ ALTER TABLE t1 IMPORT TABLESPACE;
 ERROR HY000: Got error 42 'Tablespace not found' from ./test/t1.ibd
 SET SESSION debug_dbug=@saved_debug_dbug;
 restore: t1 .ibd and .cfg files
-SET SESSION debug_dbug="+d,ib_import_check_bitmap_failure";
-ALTER TABLE t1 IMPORT TABLESPACE;
-ERROR HY000: Index for table 't1' is corrupt; try to repair it
-SET SESSION debug_dbug=@saved_debug_dbug;
-restore: t1 .ibd and .cfg files
 SET SESSION debug_dbug="+d,ib_import_cluster_root_adjust_failure";
 ALTER TABLE t1 IMPORT TABLESPACE;
 ERROR HY000: Index for table 't1' is corrupt; try to repair it
diff --git a/mysql-test/suite/innodb/r/innodb_bug59733.result b/mysql-test/suite/innodb/r/innodb_bug59733.result
deleted file mode 100644
index c962cdfd677..00000000000
--- a/mysql-test/suite/innodb/r/innodb_bug59733.result
+++ /dev/null
@@ -1,18 +0,0 @@
-CREATE TABLE bug59733(a INT AUTO_INCREMENT PRIMARY KEY,b CHAR(1))ENGINE=InnoDB;
-INSERT INTO bug59733 VALUES(0,'x');
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-CREATE INDEX b ON bug59733 (b);
-DELETE FROM bug59733 WHERE (a%100)=0;
-DROP INDEX b ON bug59733;
-CREATE INDEX b ON bug59733 (b);
-DROP TABLE bug59733;
diff --git a/mysql-test/suite/innodb/r/innodb_skip_innodb_is_tables.result b/mysql-test/suite/innodb/r/innodb_skip_innodb_is_tables.result
index bc5051b1442..ede62417652 100644
--- a/mysql-test/suite/innodb/r/innodb_skip_innodb_is_tables.result
+++ b/mysql-test/suite/innodb/r/innodb_skip_innodb_is_tables.result
@@ -116,12 +116,8 @@ buffer_LRU_unzip_search_num_scan	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	N
 buffer_LRU_unzip_search_scanned_per_call	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	set_member	Page scanned per single LRU unzip search
 buffer_page_read_index_leaf	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Index Leaf Pages read
 buffer_page_read_index_non_leaf	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Index Non-leaf Pages read
-buffer_page_read_index_ibuf_leaf	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Insert Buffer Index Leaf Pages read
-buffer_page_read_index_ibuf_non_leaf	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Insert Buffer Index Non-Leaf Pages read
 buffer_page_read_undo_log	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Undo Log Pages read
 buffer_page_read_index_inode	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Index Inode Pages read
-buffer_page_read_ibuf_free_list	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Insert Buffer Free List Pages read
-buffer_page_read_ibuf_bitmap	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Insert Buffer Bitmap Pages read
 buffer_page_read_system_page	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of System Pages read
 buffer_page_read_trx_system	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Transaction System Pages read
 buffer_page_read_fsp_hdr	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of File Space Header Pages read
@@ -132,12 +128,8 @@ buffer_page_read_zblob2	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NU
 buffer_page_read_other	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of other/unknown (old version of InnoDB) Pages read
 buffer_page_written_index_leaf	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Index Leaf Pages written
 buffer_page_written_index_non_leaf	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Index Non-leaf Pages written
-buffer_page_written_index_ibuf_leaf	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Insert Buffer Index Leaf Pages written
-buffer_page_written_index_ibuf_non_leaf	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Insert Buffer Index Non-Leaf Pages written
 buffer_page_written_undo_log	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Undo Log Pages written
 buffer_page_written_index_inode	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Index Inode Pages written
-buffer_page_written_ibuf_free_list	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Insert Buffer Free List Pages written
-buffer_page_written_ibuf_bitmap	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Insert Buffer Bitmap Pages written
 buffer_page_written_system_page	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of System Pages written
 buffer_page_written_trx_system	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Transaction System Pages written
 buffer_page_written_fsp_hdr	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of File Space Header Pages written
@@ -205,14 +197,6 @@ adaptive_hash_rows_removed	adaptive_hash_index	0	NULL	NULL	NULL	0	NULL	NULL	NULL
 adaptive_hash_rows_deleted_no_hash_entry	adaptive_hash_index	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of rows deleted that did not have corresponding Adaptive Hash Index entries
 adaptive_hash_rows_updated	adaptive_hash_index	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Adaptive Hash Index rows updated
 file_num_open_files	file_system	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	value	Number of files currently open (innodb_num_open_files)
-ibuf_merges_insert	change_buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of inserted records merged by change buffering
-ibuf_merges_delete_mark	change_buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of deleted records merged by change buffering
-ibuf_merges_delete	change_buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of purge records merged by change buffering
-ibuf_merges_discard_insert	change_buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of insert merged operations discarded
-ibuf_merges_discard_delete_mark	change_buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of deleted merged operations discarded
-ibuf_merges_discard_delete	change_buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of purge merged  operations discarded
-ibuf_merges	change_buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of change buffer merges
-ibuf_size	change_buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Change buffer size in pages
 innodb_master_thread_sleeps	server	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of times (seconds) master thread sleeps
 innodb_activity_count	server	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Current server activity count
 innodb_master_active_loops	server	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of times master thread performs its tasks when server is active
diff --git a/mysql-test/suite/innodb/r/innodb_status_variables.result b/mysql-test/suite/innodb/r/innodb_status_variables.result
index 2271cf48b14..2e8272f444b 100644
--- a/mysql-test/suite/innodb/r/innodb_status_variables.result
+++ b/mysql-test/suite/innodb/r/innodb_status_variables.result
@@ -44,16 +44,6 @@ INNODB_DBLWR_PAGES_WRITTEN
 INNODB_DBLWR_WRITES
 INNODB_DEADLOCKS
 INNODB_HISTORY_LIST_LENGTH
-INNODB_IBUF_DISCARDED_DELETE_MARKS
-INNODB_IBUF_DISCARDED_DELETES
-INNODB_IBUF_DISCARDED_INSERTS
-INNODB_IBUF_FREE_LIST
-INNODB_IBUF_MERGED_DELETE_MARKS
-INNODB_IBUF_MERGED_DELETES
-INNODB_IBUF_MERGED_INSERTS
-INNODB_IBUF_MERGES
-INNODB_IBUF_SEGMENT_SIZE
-INNODB_IBUF_SIZE
 INNODB_LOG_WAITS
 INNODB_LOG_WRITE_REQUESTS
 INNODB_LOG_WRITES
diff --git a/mysql-test/suite/innodb/r/insert_debug.result b/mysql-test/suite/innodb/r/insert_debug.result
index 3ac9df58c16..cafab4aa978 100644
--- a/mysql-test/suite/innodb/r/insert_debug.result
+++ b/mysql-test/suite/innodb/r/insert_debug.result
@@ -2,12 +2,10 @@
 # Bug#19904003 INNODB_LIMIT_OPTIMISTIC_INSERT_DEBUG=1
 # CAUSES INFINITE PAGE SPLIT
 #
-SET GLOBAL innodb_change_buffering_debug=1;
 SET GLOBAL innodb_limit_optimistic_insert_debug=1;
 CREATE TABLE t1(c1 INT PRIMARY KEY) ENGINE=InnoDB
 PARTITION BY HASH (c1) PARTITIONS 15;
 DROP TABLE t1;
-SET GLOBAL innodb_change_buffering_debug=0;
 SET GLOBAL innodb_limit_optimistic_insert_debug=0;
 #
 # Bug#25082593 FOREIGN KEY VALIDATION DOESN'T NEED
diff --git a/mysql-test/suite/innodb/r/mdev-15707.result b/mysql-test/suite/innodb/r/mdev-15707.result
deleted file mode 100644
index 3967ce48b62..00000000000
--- a/mysql-test/suite/innodb/r/mdev-15707.result
+++ /dev/null
@@ -1,24 +0,0 @@
-CREATE TABLE t1(
-a INT AUTO_INCREMENT PRIMARY KEY,
-b CHAR(255),
-INDEX(b))
-ENGINE=InnoDB;
-INSERT INTO t1(b) SELECT UUID();
-BEGIN;
-INSERT INTO t1(b) SELECT UUID() FROM t1;
-INSERT INTO t1(b) SELECT UUID() FROM t1;
-INSERT INTO t1(b) SELECT UUID() FROM t1;
-INSERT INTO t1(b) SELECT UUID() FROM t1;
-INSERT INTO t1(b) SELECT UUID() FROM t1;
-INSERT INTO t1(b) SELECT UUID() FROM t1;
-INSERT INTO t1(b) SELECT UUID() FROM t1;
-INSERT INTO t1(b) SELECT UUID() FROM t1;
-INSERT INTO t1(b) SELECT UUID() FROM t1;
-INSERT INTO t1(b) SELECT UUID() FROM t1;
-INSERT INTO t1(b) SELECT UUID() FROM t1;
-INSERT INTO t1(b) SELECT UUID() FROM t1;
-INSERT INTO t1(b) SELECT UUID() FROM t1;
-INSERT INTO t1(b) SELECT UUID() FROM t1;
-COMMIT;
-UPDATE t1 SET b=UUID();
-DROP TABLE t1;
diff --git a/mysql-test/suite/innodb/r/monitor.result b/mysql-test/suite/innodb/r/monitor.result
index 63f78752276..57f10731ed6 100644
--- a/mysql-test/suite/innodb/r/monitor.result
+++ b/mysql-test/suite/innodb/r/monitor.result
@@ -82,12 +82,8 @@ buffer_LRU_unzip_search_num_scan	disabled
 buffer_LRU_unzip_search_scanned_per_call	disabled
 buffer_page_read_index_leaf	disabled
 buffer_page_read_index_non_leaf	disabled
-buffer_page_read_index_ibuf_leaf	disabled
-buffer_page_read_index_ibuf_non_leaf	disabled
 buffer_page_read_undo_log	disabled
 buffer_page_read_index_inode	disabled
-buffer_page_read_ibuf_free_list	disabled
-buffer_page_read_ibuf_bitmap	disabled
 buffer_page_read_system_page	disabled
 buffer_page_read_trx_system	disabled
 buffer_page_read_fsp_hdr	disabled
@@ -98,12 +94,8 @@ buffer_page_read_zblob2	disabled
 buffer_page_read_other	disabled
 buffer_page_written_index_leaf	disabled
 buffer_page_written_index_non_leaf	disabled
-buffer_page_written_index_ibuf_leaf	disabled
-buffer_page_written_index_ibuf_non_leaf	disabled
 buffer_page_written_undo_log	disabled
 buffer_page_written_index_inode	disabled
-buffer_page_written_ibuf_free_list	disabled
-buffer_page_written_ibuf_bitmap	disabled
 buffer_page_written_system_page	disabled
 buffer_page_written_trx_system	disabled
 buffer_page_written_fsp_hdr	disabled
@@ -171,14 +163,6 @@ adaptive_hash_rows_removed	disabled
 adaptive_hash_rows_deleted_no_hash_entry	disabled
 adaptive_hash_rows_updated	disabled
 file_num_open_files	disabled
-ibuf_merges_insert	disabled
-ibuf_merges_delete_mark	disabled
-ibuf_merges_delete	disabled
-ibuf_merges_discard_insert	disabled
-ibuf_merges_discard_delete_mark	disabled
-ibuf_merges_discard_delete	disabled
-ibuf_merges	disabled
-ibuf_size	disabled
 innodb_master_thread_sleeps	disabled
 innodb_activity_count	disabled
 innodb_master_active_loops	disabled
diff --git a/mysql-test/suite/innodb/r/row_format_redundant.result b/mysql-test/suite/innodb/r/row_format_redundant.result
index e7e15983dfd..f0286381809 100644
--- a/mysql-test/suite/innodb/r/row_format_redundant.result
+++ b/mysql-test/suite/innodb/r/row_format_redundant.result
@@ -25,7 +25,6 @@ c varchar(150), index k1(c(99), b(56)), index k2(b(5), c(10))) engine=InnoDB
 row_format=redundant;
 insert into t3 values(444, 'dddd', 'bbbbb', 'aaaaa');
 insert into t3 values(555, 'eeee', 'ccccc', 'aaaaa');
-SET GLOBAL innodb_fast_shutdown=0;
 # restart: --innodb-data-home-dir=MYSQLTEST_VARDIR/tmp/row_format_redundant --innodb-log-group-home-dir=MYSQLTEST_VARDIR/tmp/row_format_redundant --innodb-data-file-path=ibdata1:1M:autoextend --innodb-undo-tablespaces=0 --innodb-stats-persistent=0 --innodb-read-only
 SELECT COUNT(*) FROM t1;
 COUNT(*)
@@ -68,7 +67,7 @@ DROP TABLE t1;
 Warnings:
 Warning	1932	Table 'test.t1' doesn't exist in engine
 DROP TABLE t2,t3;
-FOUND 6 /\[ERROR\] InnoDB: Table test/t1 in InnoDB data dictionary contains invalid flags\. SYS_TABLES\.TYPE=1 SYS_TABLES\.MIX_LEN=511\b/ in mysqld.1.err
+FOUND 1 /\[ERROR\] InnoDB: Table test/t1 in InnoDB data dictionary contains invalid flags\. SYS_TABLES\.TYPE=1 SYS_TABLES\.MIX_LEN=511\b.*/ in mysqld.1.err
 # restart
 ib_buffer_pool
 ib_logfile0
diff --git a/mysql-test/suite/innodb/t/ibuf_delete.test b/mysql-test/suite/innodb/t/ibuf_delete.test
deleted file mode 100644
index 82b740b6aa1..00000000000
--- a/mysql-test/suite/innodb/t/ibuf_delete.test
+++ /dev/null
@@ -1,67 +0,0 @@
---source include/have_innodb.inc
---source include/have_sequence.inc
-
-SET @buffering= @@innodb_change_buffering;
-SET GLOBAL innodb_change_buffering= deletes;
-SET @flush= @@innodb_flush_log_at_trx_commit;
-SET GLOBAL innodb_flush_log_at_trx_commit= 0;
-
-CREATE TABLE t1 (
-  a varchar(1024),
-  b varchar(1024),
-  c varchar(1024),
-  d varchar(1024),
-  e varchar(1024),
-  f varchar(1024),
-  g varchar(1024),
-  h varchar(1024),
-  key (a),
-  key (b),
-  key (c),
-  key (d)
-) ENGINE=InnoDB;
-
-INSERT INTO t1
-SELECT REPEAT('x',10), REPEAT('x',13), REPEAT('x',427), REPEAT('x',244),
-REPEAT('x',9), REPEAT('x',112), REPEAT('x',814), REPEAT('x',633)
-FROM seq_1_to_1024;
-
-CREATE TEMPORARY TABLE t2 (
-  a varchar(1024),
-  b varchar(1024),
-  c varchar(1024),
-  d varchar(1024),
-  e varchar(1024),
-  f varchar(1024),
-  g varchar(1024),
-  h varchar(1024),
-  i varchar(1024),
-  j varchar(1024),
-  k varchar(1024),
-  l varchar(1024),
-  m varchar(1024),
-  key (a),
-  key (b),
-  key (c),
-  key (d),
-  key (e),
-  key (f)
-) ENGINE=InnoDB;
-
-SET @x=REPEAT('x',512);
-INSERT INTO t2 SELECT @x, @x, @x, @x, @x, @x, @x, @x, @x, @x, @x, @x, @x
-FROM seq_1_to_768;
-
---disable_query_log
---let $run=1024
-while ($run)
-{
-  eval DELETE FROM t1 LIMIT 1 /* $run */;
-  --dec $run
-}
---enable_query_log
-
-# Cleanup
-DROP TABLE t1, t2;
-SET GLOBAL innodb_change_buffering= @buffering;
-SET GLOBAL innodb_flush_log_at_trx_commit= @flush;
diff --git a/mysql-test/suite/innodb/t/ibuf_not_empty.combinations b/mysql-test/suite/innodb/t/ibuf_not_empty.combinations
deleted file mode 100644
index c4b45dcca32..00000000000
--- a/mysql-test/suite/innodb/t/ibuf_not_empty.combinations
+++ /dev/null
@@ -1,9 +0,0 @@
-[strict_crc32]
---innodb-checksum-algorithm=strict_crc32
---innodb-page-size=4k
---innodb-force-recovery=2
-
-[strict_full_crc32]
---innodb-checksum-algorithm=strict_full_crc32
---innodb-page-size=4k
---innodb-force-recovery=2
diff --git a/mysql-test/suite/innodb/t/ibuf_not_empty.test b/mysql-test/suite/innodb/t/ibuf_not_empty.test
deleted file mode 100644
index 9362f8daffa..00000000000
--- a/mysql-test/suite/innodb/t/ibuf_not_empty.test
+++ /dev/null
@@ -1,117 +0,0 @@
---source include/have_innodb.inc
---source include/no_valgrind_without_big.inc
-# innodb_change_buffering_debug option is debug only
---source include/have_debug.inc
-# Embedded server tests do not support restarting
---source include/not_embedded.inc
---source include/have_sequence.inc
-
---disable_query_log
-call mtr.add_suppression("InnoDB: Failed to find tablespace for table `test`\\.`t1` in the cache\\. Attempting to load the tablespace with space id");
-call mtr.add_suppression("InnoDB: Allocated tablespace ID \\d+ for test.t1, old maximum was");
-call mtr.add_suppression("InnoDB: Failed to find tablespace for table `mysql`\\.`transaction_registry` in the cache\\. Attempting to load the tablespace with space id");
-call mtr.add_suppression("InnoDB: Allocated tablespace ID \\d+ for mysql.transaction_registry, old maximum was");
-call mtr.add_suppression("InnoDB: Trying to read 4096 bytes");
-call mtr.add_suppression("InnoDB: File './test/t1.ibd' is corrupted");
---enable_query_log
-
-CREATE TABLE t1(
-	a INT AUTO_INCREMENT PRIMARY KEY,
-	b CHAR(1),
-	c INT,
-	INDEX(b))
-ENGINE=InnoDB STATS_PERSISTENT=0;
-
-# The flag innodb_change_buffering_debug is only available in debug builds.
-# It instructs InnoDB to try to evict pages from the buffer pool when
-# change buffering is possible, so that the change buffer will be used
-# whenever possible.
-SET GLOBAL innodb_change_buffering_debug = 1;
-SET GLOBAL innodb_change_buffering=all;
-
-# Create enough rows for the table, so that the change buffer will be
-# used for modifying the secondary index page. There must be multiple
-# index pages, because changes to the root page are never buffered.
-INSERT INTO t1 SELECT 0,'x',1 FROM seq_1_to_1024;
-let MYSQLD_DATADIR=`select @@datadir`;
-let PAGE_SIZE=`select @@innodb_page_size`;
-
---source include/shutdown_mysqld.inc
-
-# Corrupt the change buffer bitmap, to claim that pages are clean
-perl;
-do "$ENV{MTR_SUITE_DIR}/include/crc32.pl";
-my $file = "$ENV{MYSQLD_DATADIR}/test/t1.ibd";
-open(FILE, "+<$file") || die "Unable to open $file";
-binmode FILE;
-my $ps= $ENV{PAGE_SIZE};
-my $page;
-die "Unable to read $file" unless sysread(FILE, $page, $ps) == $ps;
-my $full_crc32 = unpack("N",substr($page,54,4)) & 0x10; # FIL_SPACE_FLAGS
-die "Unable to read $file" unless sysread(FILE, $page, $ps) == $ps;
-# Clean the change buffer bitmap.
-substr($page,38,$ps - 38 - 8) = chr(0) x ($ps - 38 - 8);
-my $polynomial = 0x82f63b78; # CRC-32C
-if ($full_crc32)
-{
-    my $ck = mycrc32(substr($page, 0, $ps-4), 0, $polynomial);
-    substr($page, $ps-4, 4) = pack("N", $ck);
-}
-else
-{
-    my $ck= pack("N",mycrc32(substr($page, 4, 22), 0, $polynomial) ^
-                 mycrc32(substr($page, 38, $ps - 38 - 8), 0, $polynomial));
-    substr($page,0,4)=$ck;
-    substr($page,$ps-8,4)=$ck;
-}
-sysseek(FILE, $ps, 0) || die "Unable to rewind $file\n";
-syswrite(FILE, $page, $ps)==$ps || die "Unable to write $file\n";
-close(FILE) || die "Unable to close $file";
-EOF
-
---let $restart_parameters= --innodb-force-recovery=6 --innodb-change-buffer-dump
---source include/start_mysqld.inc
-
---replace_regex /contains \d+ entries/contains 990 entries/
-check table t1;
-
---source include/shutdown_mysqld.inc
-
-# Truncate the file to 5 pages, as if it were empty
-perl;
-do "$ENV{MTR_SUITE_DIR}/include/crc32.pl";
-my $file = "$ENV{MYSQLD_DATADIR}/test/t1.ibd";
-open(FILE, "+<$file") || die "Unable to open $file";
-binmode FILE;
-my $ps= $ENV{PAGE_SIZE};
-my $pages=5;
-my $page;
-die "Unable to read $file" unless sysread(FILE, $page, $ps) == $ps;
-my $full_crc32 = unpack("N",substr($page,54,4)) & 0x10; # FIL_SPACE_FLAGS
-substr($page,46,4)=pack("N", $pages);
-my $polynomial = 0x82f63b78; # CRC-32C
-if ($full_crc32)
-{
-    my $ck = mycrc32(substr($page, 0, $ps-4), 0, $polynomial);
-    substr($page, $ps-4, 4) = pack("N", $ck);
-}
-else
-{
-    my $ck= pack("N",mycrc32(substr($page, 4, 22), 0, $polynomial) ^
-                 mycrc32(substr($page, 38, $ps - 38 - 8), 0, $polynomial));
-    substr($page,0,4)=$ck;
-    substr($page,$ps-8,4)=$ck;
-}
-sysseek(FILE, 0, 0) || die "Unable to rewind $file\n";
-syswrite(FILE, $page, $ps)==$ps || die "Unable to write $file\n";
-truncate(FILE, $ps * $pages);
-close(FILE) || die "Unable to close $file";
-EOF
-
---let $restart_parameters=--innodb-force_recovery=0
---source include/start_mysqld.inc
-SET GLOBAL innodb_fast_shutdown=0;
---source include/restart_mysqld.inc
-
-# Cleanup
-DROP TABLE t1;
diff --git a/mysql-test/suite/innodb/t/innodb-change-buffer-recovery-master.opt b/mysql-test/suite/innodb/t/innodb-change-buffer-recovery-master.opt
deleted file mode 100644
index e5d7090c883..00000000000
--- a/mysql-test/suite/innodb/t/innodb-change-buffer-recovery-master.opt
+++ /dev/null
@@ -1 +0,0 @@
---innodb_buffer_pool_size=24M
diff --git a/mysql-test/suite/innodb/t/innodb-change-buffer-recovery.test b/mysql-test/suite/innodb/t/innodb-change-buffer-recovery.test
deleted file mode 100644
index dbce2f91948..00000000000
--- a/mysql-test/suite/innodb/t/innodb-change-buffer-recovery.test
+++ /dev/null
@@ -1,78 +0,0 @@
---echo #
---echo # Bug#69122 - INNODB DOESN'T REDO-LOG INSERT BUFFER MERGE
---echo #             OPERATION IF IT IS DONE IN-PLACE
---echo #
---source include/have_innodb.inc
-# innodb_change_buffering_debug option is debug only
---source include/have_debug.inc
-# Embedded server does not support crashing
---source include/not_embedded.inc
-# DBUG_SUICIDE() hangs under valgrind
---source include/not_valgrind.inc
-# This test is slow on buildbot.
---source include/big_test.inc
---source include/have_sequence.inc
-
-call mtr.add_suppression("InnoDB: innodb_read_only prevents crash recovery");
-call mtr.add_suppression("Plugin initialization aborted at srv0start\\.cc");
-call mtr.add_suppression("Plugin 'InnoDB'");
-FLUSH TABLES;
-
-CREATE TABLE t1(
-	a INT AUTO_INCREMENT PRIMARY KEY,
-	b CHAR(1),
-	c INT,
-	INDEX(b))
-ENGINE=InnoDB STATS_PERSISTENT=0;
-
---let $_server_id= `SELECT @@server_id`
---let $_expect_file_name= $MYSQLTEST_VARDIR/tmp/mysqld.$_server_id.expect
-
-# The flag innodb_change_buffering_debug is only available in debug builds.
-# It instructs InnoDB to try to evict pages from the buffer pool when
-# change buffering is possible, so that the change buffer will be used
-# whenever possible.
-SET GLOBAL innodb_change_buffering_debug = 1;
-SET GLOBAL innodb_change_buffering = all;
-let SEARCH_FILE = $MYSQLTEST_VARDIR/log/mysqld.1.err;
-
-# Create enough rows for the table, so that the change buffer will be
-# used for modifying the secondary index page. There must be multiple
-# index pages, because changes to the root page are never buffered.
-INSERT INTO t1 SELECT 0,'x',1 FROM seq_1_to_8192;
-
-BEGIN;
-SELECT b FROM t1 LIMIT 3;
-
-connect (con1,localhost,root,,);
-BEGIN;
-DELETE FROM t1 WHERE a=1;
-# This should be buffered, if innodb_change_buffering_debug = 1 is in effect.
-INSERT INTO t1 VALUES(1,'X',1);
-
-SET DEBUG_DBUG='+d,crash_after_log_ibuf_upd_inplace';
---exec echo "wait" > $_expect_file_name
---error 2013
-# This should force a change buffer merge
-SELECT b FROM t1 LIMIT 3;
-disconnect con1;
-connection default;
-let SEARCH_PATTERN=Wrote log record for ibuf update in place operation;
---source include/search_pattern_in_file.inc
-
---let $restart_parameters= --innodb-read-only
---source include/start_mysqld.inc
-CHECK TABLE t1;
---source include/shutdown_mysqld.inc
-let SEARCH_PATTERN=innodb_read_only prevents crash recovery;
---source include/search_pattern_in_file.inc
-
---let $restart_parameters= --innodb-force-recovery=5 --debug-dbug=d,crash_after_log_ibuf_upd_inplace
---source include/start_mysqld.inc
-SELECT * FROM t1 LIMIT 1;
-# Slow shutdown will not merge the changes due to innodb_force_recovery=5.
-SET GLOBAL innodb_fast_shutdown=0;
---let $restart_parameters=
---source include/restart_mysqld.inc
-CHECK TABLE t1;
-DROP TABLE t1;
diff --git a/mysql-test/suite/innodb/t/innodb-wl5522-debug.test b/mysql-test/suite/innodb/t/innodb-wl5522-debug.test
index 16c5713cc7b..e970bd842e2 100644
--- a/mysql-test/suite/innodb/t/innodb-wl5522-debug.test
+++ b/mysql-test/suite/innodb/t/innodb-wl5522-debug.test
@@ -952,21 +952,6 @@ do "$ENV{MTR_SUITE_DIR}/include/innodb-util.pl";
 ib_restore_tablespaces("test", "t1");
 EOF
 
-# Test failure after ibuf check
-SET SESSION debug_dbug="+d,ib_import_check_bitmap_failure";
-
-# Need proper mapping of error codes :-(
---error ER_NOT_KEYFILE
-ALTER TABLE t1 IMPORT TABLESPACE;
-
-SET SESSION debug_dbug=@saved_debug_dbug;
-
-# Restore files
-perl;
-do "$ENV{MTR_SUITE_DIR}/include/innodb-util.pl";
-ib_restore_tablespaces("test", "t1");
-EOF
-
 # Test failure after adjusting the cluster index root page
 SET SESSION debug_dbug="+d,ib_import_cluster_root_adjust_failure";
 
diff --git a/mysql-test/suite/innodb/t/innodb_buffer_pool_load_now.test b/mysql-test/suite/innodb/t/innodb_buffer_pool_load_now.test
index baced6e9e11..c9e4dc25e7f 100644
--- a/mysql-test/suite/innodb/t/innodb_buffer_pool_load_now.test
+++ b/mysql-test/suite/innodb/t/innodb_buffer_pool_load_now.test
@@ -69,7 +69,7 @@ EOF
 
 --move_file $file $file.now
 
-# Complete purge (and change buffer merge).
+# Complete purge.
 SET GLOBAL innodb_fast_shutdown=0;
 --source include/shutdown_mysqld.inc
 
diff --git a/mysql-test/suite/innodb/t/innodb_bug59733.test b/mysql-test/suite/innodb/t/innodb_bug59733.test
deleted file mode 100644
index 0b1bff51932..00000000000
--- a/mysql-test/suite/innodb/t/innodb_bug59733.test
+++ /dev/null
@@ -1,53 +0,0 @@
-#
-# Bug #59733 Possible deadlock when buffered changes are to be discarded
-# in buf_page_create
-#
--- source include/have_innodb.inc
-
--- disable_query_log
-# The flag innodb_change_buffering_debug is only available in debug builds.
-# It instructs InnoDB to try to evict pages from the buffer pool when
-# change buffering is possible, so that the change buffer will be used
-# whenever possible.
--- error 0,ER_UNKNOWN_SYSTEM_VARIABLE
-SET @innodb_change_buffering_debug_orig = @@innodb_change_buffering_debug;
--- error 0,ER_UNKNOWN_SYSTEM_VARIABLE
-SET GLOBAL innodb_change_buffering_debug = 1;
--- enable_query_log
-
-CREATE TABLE bug59733(a INT AUTO_INCREMENT PRIMARY KEY,b CHAR(1))ENGINE=InnoDB;
-
-# Create enough rows for the table, so that the insert buffer will be
-# used. There must be multiple index pages, because changes to the
-# root page are never buffered.
-
-INSERT INTO bug59733 VALUES(0,'x');
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-INSERT INTO bug59733 SELECT 0,b FROM bug59733;
-
-# Create the secondary index for which changes will be buffered.
-CREATE INDEX b ON bug59733 (b);
-
-# This should be buffered, if innodb_change_buffering_debug = 1 is in effect.
-DELETE FROM bug59733 WHERE (a%100)=0;
-
-# Drop the index in order to get free pages with orphaned buffered changes.
-DROP INDEX b ON bug59733;
-
-# Create the index and attempt to reuse pages for which buffered changes exist.
-CREATE INDEX b ON bug59733 (b);
-
-DROP TABLE bug59733;
-
--- disable_query_log
--- error 0, ER_UNKNOWN_SYSTEM_VARIABLE
-SET GLOBAL innodb_change_buffering_debug = @innodb_change_buffering_debug_orig;
diff --git a/mysql-test/suite/innodb/t/insert_debug.test b/mysql-test/suite/innodb/t/insert_debug.test
index c370c402ac7..7fe584a8ff7 100644
--- a/mysql-test/suite/innodb/t/insert_debug.test
+++ b/mysql-test/suite/innodb/t/insert_debug.test
@@ -7,13 +7,11 @@
 --echo # CAUSES INFINITE PAGE SPLIT
 --echo #
 
-SET GLOBAL innodb_change_buffering_debug=1;
 SET GLOBAL innodb_limit_optimistic_insert_debug=1;
 CREATE TABLE t1(c1 INT PRIMARY KEY) ENGINE=InnoDB
 PARTITION BY HASH (c1) PARTITIONS 15;
 DROP TABLE t1;
 
-SET GLOBAL innodb_change_buffering_debug=0;
 SET GLOBAL innodb_limit_optimistic_insert_debug=0;
 
 --echo #
diff --git a/mysql-test/suite/innodb/t/log_corruption.test b/mysql-test/suite/innodb/t/log_corruption.test
index 6f7080f5b50..f54aebf317e 100644
--- a/mysql-test/suite/innodb/t/log_corruption.test
+++ b/mysql-test/suite/innodb/t/log_corruption.test
@@ -57,16 +57,24 @@ my $head = pack("Nx[18]", 0);
 my $body = pack("x[8]Nx[10]Nx[16312]", 768, 97937874);
 my $ck = mycrc32($head, 0, $polynomial) ^ mycrc32($body, 0, $polynomial);
 print OUT pack("N",$ck).$head.pack("x[12]").$body.pack("Nx[4]",$ck);
-# Dummy pages 1..6.
-$body = pack("x[16338]");
-for (my($page) = 1; $page < 7; $page++)
-{
-    ## FIL_PAGE_OFFSET
-    $head = pack("Nx[18]", $page);
-    $ck = mycrc32($head, 0, $polynomial) ^ mycrc32($body, 0, $polynomial);
-    print OUT pack("N",$ck).$head.pack("x[16350]Nx[4]",$ck);
-}
+
+# Dummy change buffer header page (page 3).
+die unless seek(OUT, 3 * 16384, 0);
+## FIL_PAGE_OFFSET, FIL_PAGE_PREV, FIL_PAGE_NEXT, FIL_PAGE_TYPE
+my $head = pack("NNNx[8]n", 3, 0xffffffff, 0xffffffff, 6);
+my $body = pack("x[62]nnx[16272]", 2, 50);
+my $ck = mycrc32($head, 0, $polynomial) ^ mycrc32($body, 0, $polynomial);
+print OUT pack("N",$ck).$head.pack("x[12]").$body.pack("Nx[4]",$ck);
+
+# Dummy change buffer root page (page 4).
+## FIL_PAGE_OFFSET, FIL_PAGE_PREV, FIL_PAGE_NEXT
+my $head = pack("NNNx[10]", 4, 0xffffffff, 0xffffffff);
+my $body = chr(0) x 16338;
+my $ck = mycrc32($head, 0, $polynomial) ^ mycrc32($body, 0, $polynomial);
+print OUT pack("N",$ck).$head.pack("x[12]").$body.pack("Nx[4]",$ck);
+
 # Dictionary header page (page 7).
+die unless seek(OUT, 7 * 16384, 0);
 ## FIL_PAGE_OFFSET
 $head = pack("Nx[18]", 7);
 ## DICT_HDR_TABLES,DICT_HDR_INDEXES
diff --git a/mysql-test/suite/innodb/t/log_upgrade.test b/mysql-test/suite/innodb/t/log_upgrade.test
index faf88c41bef..a3d237875fe 100644
--- a/mysql-test/suite/innodb/t/log_upgrade.test
+++ b/mysql-test/suite/innodb/t/log_upgrade.test
@@ -45,9 +45,24 @@ my $head = pack("Nx[18]", 0);
 my $body = pack("x[8]Nx[10]Nx[16312]", 768, 97937874);
 my $ck = mycrc32($head, 0, $polynomial) ^ mycrc32($body, 0, $polynomial);
 print OUT pack("N",$ck).$head.pack("x[12]").$body.pack("Nx[4]",$ck);
-# Dummy pages 1..6.
-print OUT chr(0) x (6 * 16384);
+
+# Dummy change buffer header page (page 3).
+die unless seek(OUT, 3 * 16384, 0);
+## FIL_PAGE_OFFSET, FIL_PAGE_PREV, FIL_PAGE_NEXT, FIL_PAGE_TYPE
+my $head = pack("NNNx[8]n", 3, 0xffffffff, 0xffffffff, 6);
+my $body = pack("x[62]nnx[16272]", 2, 50);
+my $ck = mycrc32($head, 0, $polynomial) ^ mycrc32($body, 0, $polynomial);
+print OUT pack("N",$ck).$head.pack("x[12]").$body.pack("Nx[4]",$ck);
+
+# Dummy change buffer root page (page 4).
+## FIL_PAGE_OFFSET, FIL_PAGE_PREV, FIL_PAGE_NEXT
+my $head = pack("NNNx[10]", 4, 0xffffffff, 0xffffffff);
+my $body = chr(0) x 16338;
+my $ck = mycrc32($head, 0, $polynomial) ^ mycrc32($body, 0, $polynomial);
+print OUT pack("N",$ck).$head.pack("x[12]").$body.pack("Nx[4]",$ck);
+
 # Dictionary header page (page 7).
+die unless seek(OUT, 7 * 16384, 0);
 ## FIL_PAGE_OFFSET
 $head = pack("Nx[18]", 7);
 ## DICT_HDR_TABLES,DICT_HDR_INDEXES
diff --git a/mysql-test/suite/innodb/t/mdev-15707.opt b/mysql-test/suite/innodb/t/mdev-15707.opt
deleted file mode 100644
index fec3463c6d0..00000000000
--- a/mysql-test/suite/innodb/t/mdev-15707.opt
+++ /dev/null
@@ -1 +0,0 @@
---innodb --innodb-buffer-pool-size=5MB --innodb-read-io-threads=1 --innodb-doublewrite=0 --innodb-flush-log-at-trx-commit=0
\ No newline at end of file
diff --git a/mysql-test/suite/innodb/t/mdev-15707.test b/mysql-test/suite/innodb/t/mdev-15707.test
deleted file mode 100644
index a0446ef4f81..00000000000
--- a/mysql-test/suite/innodb/t/mdev-15707.test
+++ /dev/null
@@ -1,30 +0,0 @@
---source include/windows.inc
-# This test is slow on buildbot.
---source include/big_test.inc
-
-# Deadlock in conjunction with the innodb change buffering.
-
-# When innodb change buffering kicks in, i.e secondary non-unique index
-# does not fit into the bufferpool, then, on Windows, innodb
-# background threads could deadlock whenever index page is
-# read, and the page needs load/merge change buffer.
-# The test tries to reproduce this situation, by creating index
-# that does not fit into bufferpool, and doing a large update.
-
-CREATE TABLE t1(
-a INT AUTO_INCREMENT PRIMARY KEY,
-b CHAR(255),
-INDEX(b))
-ENGINE=InnoDB;
-
-INSERT INTO t1(b) SELECT UUID();
-BEGIN;
-let $i=`select cast(log2(@@innodb_buffer_pool_size/255) as int)`;
-while ($i)
-{
-  INSERT INTO t1(b) SELECT UUID() FROM t1;
-  dec $i;
-}
-COMMIT;
-UPDATE t1 SET b=UUID();
-DROP TABLE t1;
\ No newline at end of file
diff --git a/mysql-test/suite/innodb/t/row_format_redundant.test b/mysql-test/suite/innodb/t/row_format_redundant.test
index 6ab1eabe15b..6b5a559fc18 100644
--- a/mysql-test/suite/innodb/t/row_format_redundant.test
+++ b/mysql-test/suite/innodb/t/row_format_redundant.test
@@ -58,9 +58,6 @@ row_format=redundant;
 insert into t3 values(444, 'dddd', 'bbbbb', 'aaaaa');
 insert into t3 values(555, 'eeee', 'ccccc', 'aaaaa');
 
-# read-only restart requires the change buffer to be empty; therefore we
-# do a slow shutdown.
-SET GLOBAL innodb_fast_shutdown=0;
 --let $restart_parameters= $d --innodb-read-only
 --source include/restart_mysqld.inc
 
@@ -147,7 +144,7 @@ RENAME TABLE t1 TO tee_one;
 DROP TABLE t1;
 DROP TABLE t2,t3;
 
---let SEARCH_PATTERN= \[ERROR\] InnoDB: Table test/t1 in InnoDB data dictionary contains invalid flags\. SYS_TABLES\.TYPE=1 SYS_TABLES\.MIX_LEN=511\b
+--let SEARCH_PATTERN= \[ERROR\] InnoDB: Table test/t1 in InnoDB data dictionary contains invalid flags\. SYS_TABLES\.TYPE=1 SYS_TABLES\.MIX_LEN=511\b.*
 --source include/search_pattern_in_file.inc
 
 --let $restart_parameters=
diff --git a/mysql-test/suite/innodb_zip/r/wl5522_debug_zip.result b/mysql-test/suite/innodb_zip/r/wl5522_debug_zip.result
index 62a28a981cd..f44190680c0 100644
--- a/mysql-test/suite/innodb_zip/r/wl5522_debug_zip.result
+++ b/mysql-test/suite/innodb_zip/r/wl5522_debug_zip.result
@@ -94,11 +94,6 @@ ALTER TABLE t1 IMPORT TABLESPACE;
 ERROR HY000: Got error 42 'Tablespace not found' from ./test/t1.ibd
 SET SESSION debug_dbug=@saved_debug_dbug;
 restore: t1 .ibd and .cfg files
-SET SESSION debug_dbug="+d,ib_import_check_bitmap_failure";
-ALTER TABLE t1 IMPORT TABLESPACE;
-ERROR HY000: Index for table 't1' is corrupt; try to repair it
-SET SESSION debug_dbug=@saved_debug_dbug;
-restore: t1 .ibd and .cfg files
 SET SESSION debug_dbug="+d,ib_import_cluster_root_adjust_failure";
 ALTER TABLE t1 IMPORT TABLESPACE;
 ERROR HY000: Index for table 't1' is corrupt; try to repair it
diff --git a/mysql-test/suite/innodb_zip/t/wl5522_debug_zip.test b/mysql-test/suite/innodb_zip/t/wl5522_debug_zip.test
index 36dcd1e454b..b5bc2a94f01 100644
--- a/mysql-test/suite/innodb_zip/t/wl5522_debug_zip.test
+++ b/mysql-test/suite/innodb_zip/t/wl5522_debug_zip.test
@@ -226,21 +226,6 @@ do "$ENV{MTR_SUITE_DIR}/../innodb/include/innodb-util.pl";
 ib_restore_tablespaces("test", "t1");
 EOF
 
-# Test failure after ibuf check
-SET SESSION debug_dbug="+d,ib_import_check_bitmap_failure";
-
-# Need proper mapping of error codes :-(
---error ER_NOT_KEYFILE
-ALTER TABLE t1 IMPORT TABLESPACE;
-
-SET SESSION debug_dbug=@saved_debug_dbug;
-
-# Restore files
-perl;
-do "$ENV{MTR_SUITE_DIR}/../innodb/include/innodb-util.pl";
-ib_restore_tablespaces("test", "t1");
-EOF
-
 # Test failure after adjusting the cluster index root page
 SET SESSION debug_dbug="+d,ib_import_cluster_root_adjust_failure";
 
diff --git a/mysql-test/suite/sys_vars/r/innodb_change_buffer_max_size_basic.result b/mysql-test/suite/sys_vars/r/innodb_change_buffer_max_size_basic.result
deleted file mode 100644
index 03f11ece358..00000000000
--- a/mysql-test/suite/sys_vars/r/innodb_change_buffer_max_size_basic.result
+++ /dev/null
@@ -1,77 +0,0 @@
-SET @start_global_value = @@global.innodb_change_buffer_max_size;
-SELECT @start_global_value;
-@start_global_value
-25
-Valid values are between 0 and 50
-select @@global.innodb_change_buffer_max_size between 0 and 50;
-@@global.innodb_change_buffer_max_size between 0 and 50
-1
-select @@global.innodb_change_buffer_max_size;
-@@global.innodb_change_buffer_max_size
-25
-select @@session.innodb_change_buffer_max_size;
-ERROR HY000: Variable 'innodb_change_buffer_max_size' is a GLOBAL variable
-show global variables like 'innodb_change_buffer_max_size';
-Variable_name	Value
-innodb_change_buffer_max_size	25
-show session variables like 'innodb_change_buffer_max_size';
-Variable_name	Value
-innodb_change_buffer_max_size	25
-select * from information_schema.global_variables where variable_name='innodb_change_buffer_max_size';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_CHANGE_BUFFER_MAX_SIZE	25
-select * from information_schema.session_variables where variable_name='innodb_change_buffer_max_size';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_CHANGE_BUFFER_MAX_SIZE	25
-set global innodb_change_buffer_max_size=10;
-select @@global.innodb_change_buffer_max_size;
-@@global.innodb_change_buffer_max_size
-10
-select * from information_schema.global_variables where variable_name='innodb_change_buffer_max_size';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_CHANGE_BUFFER_MAX_SIZE	10
-select * from information_schema.session_variables where variable_name='innodb_change_buffer_max_size';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_CHANGE_BUFFER_MAX_SIZE	10
-set session innodb_change_buffer_max_size=1;
-ERROR HY000: Variable 'innodb_change_buffer_max_size' is a GLOBAL variable and should be set with SET GLOBAL
-set global innodb_change_buffer_max_size=1.1;
-ERROR 42000: Incorrect argument type to variable 'innodb_change_buffer_max_size'
-set global innodb_change_buffer_max_size=1e1;
-ERROR 42000: Incorrect argument type to variable 'innodb_change_buffer_max_size'
-set global innodb_change_buffer_max_size="foo";
-ERROR 42000: Incorrect argument type to variable 'innodb_change_buffer_max_size'
-set global innodb_change_buffer_max_size=-7;
-Warnings:
-Warning	1292	Truncated incorrect innodb_change_buffer_max_size value: '-7'
-select @@global.innodb_change_buffer_max_size;
-@@global.innodb_change_buffer_max_size
-0
-select * from information_schema.global_variables where variable_name='innodb_change_buffer_max_size';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_CHANGE_BUFFER_MAX_SIZE	0
-set global innodb_change_buffer_max_size=56;
-Warnings:
-Warning	1292	Truncated incorrect innodb_change_buffer_max_size value: '56'
-select @@global.innodb_change_buffer_max_size;
-@@global.innodb_change_buffer_max_size
-50
-select * from information_schema.global_variables where variable_name='innodb_change_buffer_max_size';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_CHANGE_BUFFER_MAX_SIZE	50
-set global innodb_change_buffer_max_size=0;
-select @@global.innodb_change_buffer_max_size;
-@@global.innodb_change_buffer_max_size
-0
-set global innodb_change_buffer_max_size=50;
-select @@global.innodb_change_buffer_max_size;
-@@global.innodb_change_buffer_max_size
-50
-set global innodb_change_buffer_max_size=DEFAULT;
-select @@global.innodb_change_buffer_max_size;
-@@global.innodb_change_buffer_max_size
-25
-SET @@global.innodb_change_buffer_max_size = @start_global_value;
-SELECT @@global.innodb_change_buffer_max_size;
-@@global.innodb_change_buffer_max_size
-25
diff --git a/mysql-test/suite/sys_vars/r/innodb_change_buffering_basic.result b/mysql-test/suite/sys_vars/r/innodb_change_buffering_basic.result
deleted file mode 100644
index f3b7ac80523..00000000000
--- a/mysql-test/suite/sys_vars/r/innodb_change_buffering_basic.result
+++ /dev/null
@@ -1,73 +0,0 @@
-SET @start_global_value = @@global.innodb_change_buffering;
-SELECT @start_global_value;
-@start_global_value
-none
-Valid values are 'all', 'deletes', 'changes', 'inserts', 'none', 'purges'
-select @@global.innodb_change_buffering in ('all', 'deletes', 'changes', 'inserts', 'none', 'purges');
-@@global.innodb_change_buffering in ('all', 'deletes', 'changes', 'inserts', 'none', 'purges')
-1
-select @@global.innodb_change_buffering;
-@@global.innodb_change_buffering
-none
-select @@session.innodb_change_buffering;
-ERROR HY000: Variable 'innodb_change_buffering' is a GLOBAL variable
-show global variables like 'innodb_change_buffering';
-Variable_name	Value
-innodb_change_buffering	none
-show session variables like 'innodb_change_buffering';
-Variable_name	Value
-innodb_change_buffering	none
-select * from information_schema.global_variables where variable_name='innodb_change_buffering';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_CHANGE_BUFFERING	none
-select * from information_schema.session_variables where variable_name='innodb_change_buffering';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_CHANGE_BUFFERING	none
-set global innodb_change_buffering='none';
-Warnings:
-Warning	1287	'@@innodb_change_buffering' is deprecated and will be removed in a future release
-select @@global.innodb_change_buffering;
-@@global.innodb_change_buffering
-none
-select * from information_schema.global_variables where variable_name='innodb_change_buffering';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_CHANGE_BUFFERING	none
-select * from information_schema.session_variables where variable_name='innodb_change_buffering';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_CHANGE_BUFFERING	none
-set @@global.innodb_change_buffering='inserts';
-Warnings:
-Warning	1287	'@@innodb_change_buffering' is deprecated and will be removed in a future release
-select @@global.innodb_change_buffering;
-@@global.innodb_change_buffering
-inserts
-select * from information_schema.global_variables where variable_name='innodb_change_buffering';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_CHANGE_BUFFERING	inserts
-select * from information_schema.session_variables where variable_name='innodb_change_buffering';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_CHANGE_BUFFERING	inserts
-set session innodb_change_buffering='some';
-ERROR HY000: Variable 'innodb_change_buffering' is a GLOBAL variable and should be set with SET GLOBAL
-set @@session.innodb_change_buffering='some';
-ERROR HY000: Variable 'innodb_change_buffering' is a GLOBAL variable and should be set with SET GLOBAL
-set global innodb_change_buffering=1.1;
-ERROR 42000: Incorrect argument type to variable 'innodb_change_buffering'
-set global innodb_change_buffering=1;
-Warnings:
-Warning	1287	'@@innodb_change_buffering' is deprecated and will be removed in a future release
-SELECT @@global.innodb_change_buffering;
-@@global.innodb_change_buffering
-inserts
-set global innodb_change_buffering=-2;
-ERROR 42000: Variable 'innodb_change_buffering' can't be set to the value of '-2'
-set global innodb_change_buffering=1e1;
-ERROR 42000: Incorrect argument type to variable 'innodb_change_buffering'
-set global innodb_change_buffering='some';
-ERROR 42000: Variable 'innodb_change_buffering' can't be set to the value of 'some'
-SET @@global.innodb_change_buffering = @start_global_value;
-Warnings:
-Warning	1287	'@@innodb_change_buffering' is deprecated and will be removed in a future release
-SELECT @@global.innodb_change_buffering;
-@@global.innodb_change_buffering
-none
diff --git a/mysql-test/suite/sys_vars/r/innodb_change_buffering_debug_basic.result b/mysql-test/suite/sys_vars/r/innodb_change_buffering_debug_basic.result
deleted file mode 100644
index 2cb3fc76e30..00000000000
--- a/mysql-test/suite/sys_vars/r/innodb_change_buffering_debug_basic.result
+++ /dev/null
@@ -1,67 +0,0 @@
-SET @start_global_value = @@global.innodb_change_buffering_debug;
-SELECT @start_global_value;
-@start_global_value
-0
-select @@global.innodb_change_buffering_debug in (0, 1);
-@@global.innodb_change_buffering_debug in (0, 1)
-1
-select @@global.innodb_change_buffering_debug;
-@@global.innodb_change_buffering_debug
-0
-select @@session.innodb_change_buffering_debug;
-ERROR HY000: Variable 'innodb_change_buffering_debug' is a GLOBAL variable
-show global variables like 'innodb_change_buffering_debug';
-Variable_name	Value
-innodb_change_buffering_debug	0
-show session variables like 'innodb_change_buffering_debug';
-Variable_name	Value
-innodb_change_buffering_debug	0
-select * from information_schema.global_variables where variable_name='innodb_change_buffering_debug';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_CHANGE_BUFFERING_DEBUG	0
-select * from information_schema.session_variables where variable_name='innodb_change_buffering_debug';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_CHANGE_BUFFERING_DEBUG	0
-set global innodb_change_buffering_debug=1;
-select @@global.innodb_change_buffering_debug;
-@@global.innodb_change_buffering_debug
-1
-select * from information_schema.global_variables where variable_name='innodb_change_buffering_debug';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_CHANGE_BUFFERING_DEBUG	1
-select * from information_schema.session_variables where variable_name='innodb_change_buffering_debug';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_CHANGE_BUFFERING_DEBUG	1
-set @@global.innodb_change_buffering_debug=0;
-select @@global.innodb_change_buffering_debug;
-@@global.innodb_change_buffering_debug
-0
-select * from information_schema.global_variables where variable_name='innodb_change_buffering_debug';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_CHANGE_BUFFERING_DEBUG	0
-select * from information_schema.session_variables where variable_name='innodb_change_buffering_debug';
-VARIABLE_NAME	VARIABLE_VALUE
-INNODB_CHANGE_BUFFERING_DEBUG	0
-set session innodb_change_buffering_debug='some';
-ERROR HY000: Variable 'innodb_change_buffering_debug' is a GLOBAL variable and should be set with SET GLOBAL
-set @@session.innodb_change_buffering_debug='some';
-ERROR HY000: Variable 'innodb_change_buffering_debug' is a GLOBAL variable and should be set with SET GLOBAL
-set global innodb_change_buffering_debug=1.1;
-ERROR 42000: Incorrect argument type to variable 'innodb_change_buffering_debug'
-set global innodb_change_buffering_debug='foo';
-ERROR 42000: Incorrect argument type to variable 'innodb_change_buffering_debug'
-set global innodb_change_buffering_debug=-2;
-Warnings:
-Warning	1292	Truncated incorrect innodb_change_buffering_debug value: '-2'
-set global innodb_change_buffering_debug=1e1;
-ERROR 42000: Incorrect argument type to variable 'innodb_change_buffering_debug'
-set global innodb_change_buffering_debug=2;
-Warnings:
-Warning	1292	Truncated incorrect innodb_change_buffering_debug value: '2'
-select @@global.innodb_change_buffering_debug;
-@@global.innodb_change_buffering_debug
-1
-SET @@global.innodb_change_buffering_debug = @start_global_value;
-SELECT @@global.innodb_change_buffering_debug;
-@@global.innodb_change_buffering_debug
-0
diff --git a/mysql-test/suite/sys_vars/r/sysvars_innodb.result b/mysql-test/suite/sys_vars/r/sysvars_innodb.result
index 998d82587b6..53c02d96206 100644
--- a/mysql-test/suite/sys_vars/r/sysvars_innodb.result
+++ b/mysql-test/suite/sys_vars/r/sysvars_innodb.result
@@ -223,54 +223,6 @@ NUMERIC_BLOCK_SIZE	NULL
 ENUM_VALUE_LIST	OFF,ON
 READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	OPTIONAL
-VARIABLE_NAME	INNODB_CHANGE_BUFFERING
-SESSION_VALUE	NULL
-DEFAULT_VALUE	none
-VARIABLE_SCOPE	GLOBAL
-VARIABLE_TYPE	ENUM
-VARIABLE_COMMENT	Buffer changes to secondary indexes.
-NUMERIC_MIN_VALUE	NULL
-NUMERIC_MAX_VALUE	NULL
-NUMERIC_BLOCK_SIZE	NULL
-ENUM_VALUE_LIST	none,inserts,deletes,changes,purges,all
-READ_ONLY	NO
-COMMAND_LINE_ARGUMENT	REQUIRED
-VARIABLE_NAME	INNODB_CHANGE_BUFFERING_DEBUG
-SESSION_VALUE	NULL
-DEFAULT_VALUE	0
-VARIABLE_SCOPE	GLOBAL
-VARIABLE_TYPE	INT UNSIGNED
-VARIABLE_COMMENT	Debug flags for InnoDB change buffering (0=none, 1=try to buffer)
-NUMERIC_MIN_VALUE	0
-NUMERIC_MAX_VALUE	1
-NUMERIC_BLOCK_SIZE	0
-ENUM_VALUE_LIST	NULL
-READ_ONLY	NO
-COMMAND_LINE_ARGUMENT	REQUIRED
-VARIABLE_NAME	INNODB_CHANGE_BUFFER_DUMP
-SESSION_VALUE	NULL
-DEFAULT_VALUE	OFF
-VARIABLE_SCOPE	GLOBAL
-VARIABLE_TYPE	BOOLEAN
-VARIABLE_COMMENT	Dump the change buffer at startup.
-NUMERIC_MIN_VALUE	NULL
-NUMERIC_MAX_VALUE	NULL
-NUMERIC_BLOCK_SIZE	NULL
-ENUM_VALUE_LIST	OFF,ON
-READ_ONLY	YES
-COMMAND_LINE_ARGUMENT	NONE
-VARIABLE_NAME	INNODB_CHANGE_BUFFER_MAX_SIZE
-SESSION_VALUE	NULL
-DEFAULT_VALUE	25
-VARIABLE_SCOPE	GLOBAL
-VARIABLE_TYPE	INT UNSIGNED
-VARIABLE_COMMENT	Maximum on-disk size of change buffer in terms of percentage of the buffer pool.
-NUMERIC_MIN_VALUE	0
-NUMERIC_MAX_VALUE	50
-NUMERIC_BLOCK_SIZE	0
-ENUM_VALUE_LIST	NULL
-READ_ONLY	NO
-COMMAND_LINE_ARGUMENT	REQUIRED
 VARIABLE_NAME	INNODB_CHECKSUM_ALGORITHM
 SESSION_VALUE	NULL
 DEFAULT_VALUE	full_crc32
diff --git a/mysql-test/suite/sys_vars/t/innodb_change_buffer_max_size_basic.test b/mysql-test/suite/sys_vars/t/innodb_change_buffer_max_size_basic.test
deleted file mode 100644
index 2094ef3dc0b..00000000000
--- a/mysql-test/suite/sys_vars/t/innodb_change_buffer_max_size_basic.test
+++ /dev/null
@@ -1,71 +0,0 @@
-
-
-# 2011-02-09 - Added
-#
-
---source include/have_innodb.inc
-
-SET @start_global_value = @@global.innodb_change_buffer_max_size;
-SELECT @start_global_value;
-
-#
-# exists as global only
-#
---echo Valid values are between 0 and 50
-select @@global.innodb_change_buffer_max_size between 0 and 50;
-select @@global.innodb_change_buffer_max_size;
---error ER_INCORRECT_GLOBAL_LOCAL_VAR
-select @@session.innodb_change_buffer_max_size;
-show global variables like 'innodb_change_buffer_max_size';
-show session variables like 'innodb_change_buffer_max_size';
---disable_warnings
-select * from information_schema.global_variables where variable_name='innodb_change_buffer_max_size';
-select * from information_schema.session_variables where variable_name='innodb_change_buffer_max_size';
---enable_warnings
-
-#
-# show that it's writable
-#
-set global innodb_change_buffer_max_size=10;
-select @@global.innodb_change_buffer_max_size;
---disable_warnings
-select * from information_schema.global_variables where variable_name='innodb_change_buffer_max_size';
-select * from information_schema.session_variables where variable_name='innodb_change_buffer_max_size';
---enable_warnings
---error ER_GLOBAL_VARIABLE
-set session innodb_change_buffer_max_size=1;
-
-#
-# incorrect types
-#
---error ER_WRONG_TYPE_FOR_VAR
-set global innodb_change_buffer_max_size=1.1;
---error ER_WRONG_TYPE_FOR_VAR
-set global innodb_change_buffer_max_size=1e1;
---error ER_WRONG_TYPE_FOR_VAR
-set global innodb_change_buffer_max_size="foo";
-
-set global innodb_change_buffer_max_size=-7;
-select @@global.innodb_change_buffer_max_size;
---disable_warnings
-select * from information_schema.global_variables where variable_name='innodb_change_buffer_max_size';
---enable_warnings
-set global innodb_change_buffer_max_size=56;
-select @@global.innodb_change_buffer_max_size;
---disable_warnings
-select * from information_schema.global_variables where variable_name='innodb_change_buffer_max_size';
---enable_warnings
-
-#
-# min/max/DEFAULT values
-#
-set global innodb_change_buffer_max_size=0;
-select @@global.innodb_change_buffer_max_size;
-set global innodb_change_buffer_max_size=50;
-select @@global.innodb_change_buffer_max_size;
-set global innodb_change_buffer_max_size=DEFAULT;
-select @@global.innodb_change_buffer_max_size;
-
-
-SET @@global.innodb_change_buffer_max_size = @start_global_value;
-SELECT @@global.innodb_change_buffer_max_size;
diff --git a/mysql-test/suite/sys_vars/t/innodb_change_buffering_basic.test b/mysql-test/suite/sys_vars/t/innodb_change_buffering_basic.test
deleted file mode 100644
index 19f0890feff..00000000000
--- a/mysql-test/suite/sys_vars/t/innodb_change_buffering_basic.test
+++ /dev/null
@@ -1,65 +0,0 @@
-
-
-# 2010-01-25 - Added
-#
-
---source include/have_innodb.inc
-
-SET @start_global_value = @@global.innodb_change_buffering;
-SELECT @start_global_value;
-
-#
-# exists as global only
-#
---echo Valid values are 'all', 'deletes', 'changes', 'inserts', 'none', 'purges'
-select @@global.innodb_change_buffering in ('all', 'deletes', 'changes', 'inserts', 'none', 'purges');
-select @@global.innodb_change_buffering;
---error ER_INCORRECT_GLOBAL_LOCAL_VAR
-select @@session.innodb_change_buffering;
-show global variables like 'innodb_change_buffering';
-show session variables like 'innodb_change_buffering';
---disable_warnings
-select * from information_schema.global_variables where variable_name='innodb_change_buffering';
-select * from information_schema.session_variables where variable_name='innodb_change_buffering';
---enable_warnings
-
-#
-# show that it's writable
-#
-set global innodb_change_buffering='none';
-select @@global.innodb_change_buffering;
---disable_warnings
-select * from information_schema.global_variables where variable_name='innodb_change_buffering';
-select * from information_schema.session_variables where variable_name='innodb_change_buffering';
---enable_warnings
-set @@global.innodb_change_buffering='inserts';
-select @@global.innodb_change_buffering;
---disable_warnings
-select * from information_schema.global_variables where variable_name='innodb_change_buffering';
-select * from information_schema.session_variables where variable_name='innodb_change_buffering';
---enable_warnings
---error ER_GLOBAL_VARIABLE
-set session innodb_change_buffering='some';
---error ER_GLOBAL_VARIABLE
-set @@session.innodb_change_buffering='some';
-
-#
-# incorrect types
-#
---error ER_WRONG_TYPE_FOR_VAR
-set global innodb_change_buffering=1.1;
-set global innodb_change_buffering=1;
-SELECT @@global.innodb_change_buffering;
---error ER_WRONG_VALUE_FOR_VAR
-set global innodb_change_buffering=-2;
---error ER_WRONG_TYPE_FOR_VAR
-set global innodb_change_buffering=1e1;
---error ER_WRONG_VALUE_FOR_VAR
-set global innodb_change_buffering='some';
-
-#
-# Cleanup
-#
-
-SET @@global.innodb_change_buffering = @start_global_value;
-SELECT @@global.innodb_change_buffering;
diff --git a/mysql-test/suite/sys_vars/t/innodb_change_buffering_debug_basic.test b/mysql-test/suite/sys_vars/t/innodb_change_buffering_debug_basic.test
deleted file mode 100644
index 70f8bee1523..00000000000
--- a/mysql-test/suite/sys_vars/t/innodb_change_buffering_debug_basic.test
+++ /dev/null
@@ -1,59 +0,0 @@
---source include/have_innodb.inc
---source include/have_debug.inc
-
-SET @start_global_value = @@global.innodb_change_buffering_debug;
-SELECT @start_global_value;
-
-#
-# exists as global only
-#
-select @@global.innodb_change_buffering_debug in (0, 1);
-select @@global.innodb_change_buffering_debug;
---error ER_INCORRECT_GLOBAL_LOCAL_VAR
-select @@session.innodb_change_buffering_debug;
-show global variables like 'innodb_change_buffering_debug';
-show session variables like 'innodb_change_buffering_debug';
---disable_warnings
-select * from information_schema.global_variables where variable_name='innodb_change_buffering_debug';
-select * from information_schema.session_variables where variable_name='innodb_change_buffering_debug';
---enable_warnings
-
-#
-# show that it's writable
-#
-set global innodb_change_buffering_debug=1;
-select @@global.innodb_change_buffering_debug;
---disable_warnings
-select * from information_schema.global_variables where variable_name='innodb_change_buffering_debug';
-select * from information_schema.session_variables where variable_name='innodb_change_buffering_debug';
---enable_warnings
-set @@global.innodb_change_buffering_debug=0;
-select @@global.innodb_change_buffering_debug;
---disable_warnings
-select * from information_schema.global_variables where variable_name='innodb_change_buffering_debug';
-select * from information_schema.session_variables where variable_name='innodb_change_buffering_debug';
---enable_warnings
---error ER_GLOBAL_VARIABLE
-set session innodb_change_buffering_debug='some';
---error ER_GLOBAL_VARIABLE
-set @@session.innodb_change_buffering_debug='some';
-
-#
-# incorrect types
-#
---error ER_WRONG_TYPE_FOR_VAR
-set global innodb_change_buffering_debug=1.1;
---error ER_WRONG_TYPE_FOR_VAR
-set global innodb_change_buffering_debug='foo';
-set global innodb_change_buffering_debug=-2;
---error ER_WRONG_TYPE_FOR_VAR
-set global innodb_change_buffering_debug=1e1;
-set global innodb_change_buffering_debug=2;
-select @@global.innodb_change_buffering_debug;
-
-#
-# Cleanup
-#
-
-SET @@global.innodb_change_buffering_debug = @start_global_value;
-SELECT @@global.innodb_change_buffering_debug;
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index afc1ec543c2..93aa7380ad5 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -1,5 +1,5 @@
 /* Copyright (c) 2000, 2015, Oracle and/or its affiliates.
-   Copyright (c) 2008, 2022, MariaDB
+   Copyright (c) 2008, 2023, MariaDB
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -5324,6 +5324,10 @@ static int init_server_components()
       MARIADB_REMOVED_OPTION("innodb-thread-concurrency"),
       MARIADB_REMOVED_OPTION("innodb-thread-sleep-delay"),
       MARIADB_REMOVED_OPTION("innodb-undo-logs"),
+
+      /* The following options were deprecated in 10.9 */
+      MARIADB_REMOVED_OPTION("innodb-change-buffering"),
+
       {0, 0, 0, 0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0}
     };
     /*
diff --git a/storage/innobase/CMakeLists.txt b/storage/innobase/CMakeLists.txt
index 49b363b76d3..848855b41e5 100644
--- a/storage/innobase/CMakeLists.txt
+++ b/storage/innobase/CMakeLists.txt
@@ -1,6 +1,6 @@
 
 # Copyright (c) 2006, 2017, Oracle and/or its affiliates. All rights reserved.
-# Copyright (c) 2014, 2022, MariaDB Corporation.
+# Copyright (c) 2014, 2023, MariaDB Corporation.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -270,7 +270,6 @@ SET(INNOBASE_SOURCES
 	include/handler0alter.h
 	include/hash0hash.h
 	include/ibuf0ibuf.h
-	include/ibuf0ibuf.inl
 	include/lock0iter.h
 	include/lock0lock.h
 	include/lock0lock.inl
diff --git a/storage/innobase/btr/btr0btr.cc b/storage/innobase/btr/btr0btr.cc
index 73d88596743..99cb135e019 100644
--- a/storage/innobase/btr/btr0btr.cc
+++ b/storage/innobase/btr/btr0btr.cc
@@ -2,7 +2,7 @@
 
 Copyright (c) 1994, 2016, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2012, Facebook Inc.
-Copyright (c) 2014, 2022, MariaDB Corporation.
+Copyright (c) 2014, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -37,7 +37,6 @@ Created 6/2/1994 Heikki Tuuri
 #include "btr0defragment.h"
 #include "rem0cmp.h"
 #include "lock0lock.h"
-#include "ibuf0ibuf.h"
 #include "trx0trx.h"
 #include "srv0mon.h"
 #include "gis0geo.h"
@@ -181,9 +180,8 @@ we allocate pages for the non-leaf levels of the tree.
 @param block       B-tree root page
 @param space       tablespace
 @return whether the segment header is valid */
-static bool btr_root_fseg_validate(ulint offset,
-                                   const buf_block_t &block,
-                                   const fil_space_t &space)
+bool btr_root_fseg_validate(ulint offset, const buf_block_t &block,
+                            const fil_space_t &space)
 {
   ut_ad(block.page.id().space() == space.id);
   const uint16_t hdr= mach_read_from_2(offset + FSEG_HDR_OFFSET +
@@ -213,12 +211,11 @@ ATTRIBUTE_COLD void btr_decryption_failed(const dict_index_t &index)
 @param[in]	index	index tree
 @param[in]	page	page number
 @param[in]	mode	latch mode
-@param[in]	merge	whether change buffer merge should be attempted
 @param[in,out]	mtr	mini-transaction
 @param[out]	err	error code
 @return block */
 buf_block_t *btr_block_get(const dict_index_t &index,
-                           uint32_t page, ulint mode, bool merge,
+                           uint32_t page, ulint mode,
                            mtr_t *mtr, dberr_t *err)
 {
   dberr_t local_err;
@@ -227,7 +224,7 @@ buf_block_t *btr_block_get(const dict_index_t &index,
   buf_block_t *block=
     buf_page_get_gen(page_id_t{index.table->space->id, page},
                      index.table->space->zip_size(), mode, nullptr, BUF_GET,
-                     mtr, err, merge && !index.is_clust());
+                     mtr, err);
   ut_ad(!block == (*err != DB_SUCCESS));
 
   if (UNIV_LIKELY(block != nullptr))
@@ -266,15 +263,13 @@ btr_root_block_get(
     return nullptr;
   }
 
-  buf_block_t *block = btr_block_get(*index, index->page, mode, false, mtr,
-                                     err);
+  buf_block_t *block = btr_block_get(*index, index->page, mode, mtr, err);
   if (block)
   {
-    if (index->is_ibuf());
-    else if (!btr_root_fseg_validate(FIL_PAGE_DATA + PAGE_BTR_SEG_LEAF,
-                                     *block, *index->table->space) ||
-             !btr_root_fseg_validate(FIL_PAGE_DATA + PAGE_BTR_SEG_TOP,
-                                     *block, *index->table->space))
+    if (!btr_root_fseg_validate(FIL_PAGE_DATA + PAGE_BTR_SEG_LEAF,
+                                *block, *index->table->space) ||
+        !btr_root_fseg_validate(FIL_PAGE_DATA + PAGE_BTR_SEG_TOP,
+                                *block, *index->table->space))
     {
       *err= DB_CORRUPTION;
       block= nullptr;
@@ -461,45 +456,12 @@ btr_page_create(
 }
 
 /**************************************************************//**
-Allocates a new file page to be used in an ibuf tree. Takes the page from
-the free list of the tree, which must contain pages!
-@return new allocated block, x-latched */
-static
-buf_block_t*
-btr_page_alloc_for_ibuf(
-/*====================*/
-	dict_index_t*	index,	/*!< in: index tree */
-	mtr_t*		mtr,	/*!< in: mtr */
-	dberr_t*	err)	/*!< out: error code */
-{
-  buf_block_t *root= btr_root_block_get(index, RW_SX_LATCH, mtr, err);
-  if (UNIV_UNLIKELY(!root))
-    return root;
-
-  buf_block_t *new_block=
-    buf_page_get_gen(page_id_t(index->table->space_id,
-                               mach_read_from_4(PAGE_HEADER +
-                                                PAGE_BTR_IBUF_FREE_LIST +
-                                                FLST_FIRST + FIL_ADDR_PAGE +
-                                                root->page.frame)),
-                     index->table->space->zip_size(), RW_X_LATCH, nullptr,
-                     BUF_GET, mtr, err);
-  if (new_block)
-    *err= flst_remove(root, PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST, new_block,
-                PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST_NODE, mtr);
-  ut_d(if (*err == DB_SUCCESS)
-         flst_validate(root, PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST, mtr));
-  return new_block;
-}
-
-/**************************************************************//**
 Allocates a new file page to be used in an index tree. NOTE: we assume
 that the caller has made the reservation for free extents!
 @retval NULL if no page could be allocated */
-static MY_ATTRIBUTE((nonnull, warn_unused_result))
+MY_ATTRIBUTE((nonnull, warn_unused_result))
 buf_block_t*
-btr_page_alloc_low(
-/*===============*/
+btr_page_alloc(
 	dict_index_t*	index,		/*!< in: index */
 	uint32_t	hint_page_no,	/*!< in: hint of a good page */
 	byte		file_direction,	/*!< in: direction where a possible
@@ -513,6 +475,8 @@ btr_page_alloc_low(
 					page should be initialized. */
 	dberr_t*	err)		/*!< out: error code */
 {
+  ut_ad(level < BTR_MAX_NODE_LEVEL);
+
   const auto savepoint= mtr->get_savepoint();
   buf_block_t *root= btr_root_block_get(index, RW_NO_LATCH, mtr, err);
   if (UNIV_UNLIKELY(!root))
@@ -540,57 +504,6 @@ btr_page_alloc_low(
                                       true, mtr, init_mtr, err);
 }
 
-/**************************************************************//**
-Allocates a new file page to be used in an index tree. NOTE: we assume
-that the caller has made the reservation for free extents!
-@retval NULL if no page could be allocated */
-buf_block_t*
-btr_page_alloc(
-/*===========*/
-	dict_index_t*	index,		/*!< in: index */
-	uint32_t	hint_page_no,	/*!< in: hint of a good page */
-	byte		file_direction,	/*!< in: direction where a possible
-					page split is made */
-	ulint		level,		/*!< in: level where the page is placed
-					in the tree */
-	mtr_t*		mtr,		/*!< in/out: mini-transaction
-					for the allocation */
-	mtr_t*		init_mtr,	/*!< in/out: mini-transaction
-					for x-latching and initializing
-					the page */
-	dberr_t*	err)		/*!< out: error code */
-{
-  ut_ad(level < BTR_MAX_NODE_LEVEL);
-  return index->is_ibuf()
-    ? btr_page_alloc_for_ibuf(index, mtr, err)
-    : btr_page_alloc_low(index, hint_page_no, file_direction, level,
-                         mtr, init_mtr, err);
-}
-
-/**************************************************************//**
-Frees a page used in an ibuf tree. Puts the page to the free list of the
-ibuf tree. */
-static
-dberr_t
-btr_page_free_for_ibuf(
-/*===================*/
-	dict_index_t*	index,	/*!< in: index tree */
-	buf_block_t*	block,	/*!< in: block to be freed, x-latched */
-	mtr_t*		mtr)	/*!< in: mtr */
-{
-  ut_ad(mtr->memo_contains_flagged(block, MTR_MEMO_PAGE_X_FIX));
-
-  dberr_t err;
-  if (buf_block_t *root= btr_root_block_get(index, RW_SX_LATCH, mtr, &err))
-  {
-    err= flst_add_first(root, PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST,
-                   block, PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST_NODE, mtr);
-    ut_d(if (err == DB_SUCCESS)
-           flst_validate(root, PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST, mtr));
-  }
-  return err;
-}
-
 /** Free an index page.
 @param[in,out]	index	index tree
 @param[in,out]	block	block to be freed
@@ -623,9 +536,6 @@ dberr_t btr_page_free(dict_index_t* index, buf_block_t* block, mtr_t* mtr,
   The page will be freed, so previous changes to it by this
   mini-transaction should not matter. */
 
-  if (index->is_ibuf())
-    return btr_page_free_for_ibuf(index, block, mtr);
-
   fil_space_t *space= index->table->space;
   dberr_t err;
 
@@ -708,8 +618,7 @@ btr_node_ptr_get_child(
 
 	return btr_block_get(
 		*index, btr_node_ptr_get_child_page_no(node_ptr, offsets),
-		RW_SX_LATCH, btr_page_get_level(page_align(node_ptr)) == 1,
-		mtr, err);
+		RW_SX_LATCH, mtr, err);
 }
 
 MY_ATTRIBUTE((nonnull(2,3,5), warn_unused_result))
@@ -930,77 +839,32 @@ btr_create(
 	mtr_t*			mtr,
 	dberr_t*		err)
 {
-	buf_block_t*		block;
-
 	ut_ad(mtr->is_named_space(space));
 	ut_ad(index_id != BTR_FREED_INDEX_ID);
 	ut_ad(index || space == fil_system.sys_space);
 
-	/* Create the two new segments (one, in the case of an ibuf tree) for
-	the index tree; the segment headers are put on the allocated root page
-	(for an ibuf tree, not in the root, but on a separate ibuf header
-	page) */
+	/* Create the two new segments for the index tree;
+	the segment headers are put on the allocated root page */
 
-	if (UNIV_UNLIKELY(type & DICT_IBUF)) {
-		/* Allocate first the ibuf header page */
-		buf_block_t*	ibuf_hdr_block = fseg_create(
-			space, IBUF_HEADER + IBUF_TREE_SEG_HEADER, mtr, err);
+	buf_block_t *block = fseg_create(space, PAGE_HEADER + PAGE_BTR_SEG_TOP,
+					 mtr, err);
 
-		if (ibuf_hdr_block == NULL) {
-			return(FIL_NULL);
-		}
-
-		ut_ad(ibuf_hdr_block->page.id().page_no()
-		      == IBUF_HEADER_PAGE_NO);
-		/* Allocate then the next page to the segment: it will be the
-		tree root page */
-
-		block = fseg_alloc_free_page_general(
-			buf_block_get_frame(ibuf_hdr_block)
-			+ IBUF_HEADER + IBUF_TREE_SEG_HEADER,
-			IBUF_TREE_ROOT_PAGE_NO,
-			FSP_UP, false, mtr, mtr, err);
-
-		if (block == NULL) {
-			return(FIL_NULL);
-		}
-
-		ut_ad(block->page.id() == page_id_t(0,IBUF_TREE_ROOT_PAGE_NO));
-
-		flst_init(block, PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST, mtr);
-	} else {
-		block = fseg_create(space, PAGE_HEADER + PAGE_BTR_SEG_TOP,
-				    mtr, err);
-
-		if (block == NULL) {
-			return(FIL_NULL);
-		}
+	if (!block) {
+		return FIL_NULL;
+	}
 
-		if (!fseg_create(space, PAGE_HEADER + PAGE_BTR_SEG_LEAF, mtr,
-				 err, false, block)) {
-			/* Not enough space for new segment, free root
-			segment before return. */
-			btr_free_root(block, *space, mtr);
-			return(FIL_NULL);
-		}
+	if (!fseg_create(space, PAGE_HEADER + PAGE_BTR_SEG_LEAF, mtr,
+			 err, false, block)) {
+		/* Not enough space for new segment, free root
+		segment before return. */
+		btr_free_root(block, *space, mtr);
+		return FIL_NULL;
 	}
 
 	ut_ad(!page_has_siblings(block->page.frame));
 
 	btr_root_page_init(block, index_id, index, mtr);
 
-	/* We reset the free bits for the page in a separate
-	mini-transaction to allow creation of several trees in the
-	same mtr, otherwise the latch on a bitmap page would prevent
-	it because of the latching order.
-
-	Note: Insert Buffering is disabled for temporary tables given that
-	most temporary tables are smaller in size and short-lived. */
-	if (!(type & DICT_CLUSTERED)
-	    && (!index || !index->table->is_temporary())) {
-		ibuf_reset_free_bits(block);
-	}
-
 	/* In the following assertion we test that two records of maximum
 	allowed size fit on the root page: this fact is needed to ensure
 	correctness of split algorithms */
@@ -1152,7 +1016,7 @@ void btr_drop_temporary_table(const dict_table_t &table)
   {
     if (buf_block_t *block= buf_page_get_low({SRV_TMP_SPACE_ID, index->page}, 0,
                                              RW_X_LATCH, nullptr, BUF_GET, &mtr,
-                                             nullptr, false))
+                                             nullptr))
     {
       btr_free_but_not_root(block, MTR_LOG_NO_REDO);
       mtr.set_log_mode(MTR_LOG_NO_REDO);
@@ -1323,18 +1187,18 @@ static dberr_t btr_page_reorganize_low(page_cur_t *cursor, mtr_t *mtr)
   if (page_get_max_trx_id(block->page.frame))
     /* PAGE_MAX_TRX_ID must be zero on non-leaf pages other than
     clustered index root pages. */
-    ut_ad(dict_index_is_sec_or_ibuf(cursor->index)
+    ut_ad(!cursor->index->is_primary()
           ? page_is_leaf(block->page.frame)
           : block->page.id().page_no() == cursor->index->page);
   else
     /* PAGE_MAX_TRX_ID is unused in clustered index pages (other than
     the root where it is repurposed as PAGE_ROOT_AUTO_INC), non-leaf
     pages, and in temporary tables.  It was always zero-initialized in
-    page_create().  PAGE_MAX_TRX_ID must be nonzero on
-    dict_index_is_sec_or_ibuf() leaf pages. */
+    page_create().  PAGE_MAX_TRX_ID must be nonzero on secondary index
+    leaf pages. */
     ut_ad(cursor->index->table->is_temporary() ||
           !page_is_leaf(block->page.frame) ||
-          !dict_index_is_sec_or_ibuf(cursor->index));
+          cursor->index->is_primary());
 #endif
 
   const uint16_t data_size1= page_get_data_size(old->page.frame);
@@ -1534,15 +1398,7 @@ static dberr_t btr_page_reorganize_low(page_cur_t *cursor, mtr_t *mtr)
   return DB_SUCCESS;
 }
 
-/*************************************************************//**
-Reorganizes an index page.
-
-IMPORTANT: On success, the caller will have to update IBUF_BITMAP_FREE
-if this is a compressed leaf page in a secondary index. This has to
-be done either within the same mini-transaction, or by invoking
-ibuf_reset_free_bits() before mtr_commit(). On uncompressed pages,
-IBUF_BITMAP_FREE is unaffected by reorganization.
-
+/** Reorganize an index page.
 @return error code
 @retval DB_FAIL if reorganizing a ROW_FORMAT=COMPRESSED page failed */
 dberr_t
@@ -1561,15 +1417,7 @@ btr_page_reorganize_block(
   return btr_page_reorganize_low(&cur, mtr);
 }
 
-/*************************************************************//**
-Reorganizes an index page.
-
-IMPORTANT: On success, the caller will have to update IBUF_BITMAP_FREE
-if this is a compressed leaf page in a secondary index. This has to
-be done either within the same mini-transaction, or by invoking
-ibuf_reset_free_bits() before mtr_commit(). On uncompressed pages,
-IBUF_BITMAP_FREE is unaffected by reorganization.
-
+/** Reorganize an index page.
 @param cursor  page cursor
 @param mtr     mini-transaction
 @return error code
@@ -1800,6 +1648,7 @@ btr_root_raise_and_insert(
 	ut_ad(!page_is_empty(root->page.frame));
 	index = btr_cur_get_index(cursor);
 	ut_ad(index->n_core_null_bytes <= UT_BITS_IN_BYTES(index->n_nullable));
+	ut_ad(!index->is_spatial());
 #ifdef UNIV_ZIP_DEBUG
 	ut_a(!root_page_zip
 	     || page_zip_validate(root_page_zip, root->page.frame, index));
@@ -1815,12 +1664,11 @@ btr_root_raise_and_insert(
 		return nullptr;
 	}
 
-	if (index->is_ibuf()) {
-        } else if (!btr_root_fseg_validate(FIL_PAGE_DATA + PAGE_BTR_SEG_LEAF,
-                                           *root, *index->table->space)
-                   || !btr_root_fseg_validate(FIL_PAGE_DATA + PAGE_BTR_SEG_TOP,
-                                              *root, *index->table->space)) {
-                return nullptr;
+	if (!btr_root_fseg_validate(FIL_PAGE_DATA + PAGE_BTR_SEG_LEAF,
+				    *root, *index->table->space)
+	    || !btr_root_fseg_validate(FIL_PAGE_DATA + PAGE_BTR_SEG_TOP,
+				       *root, *index->table->space)) {
+		return nullptr;
 	}
 
 	/* Allocate a new page to the tree. Root splitting is done by first
@@ -1891,18 +1739,12 @@ btr_root_raise_and_insert(
 				page_get_infimum_rec(root->page.frame));
 		}
 
-		/* Move any existing predicate locks */
-		if (dict_index_is_spatial(index)) {
-			lock_prdt_rec_move(new_block, root_id);
-		} else {
-			btr_search_move_or_delete_hash_entries(
-				new_block, root);
-		}
+		btr_search_move_or_delete_hash_entries(new_block, root);
 	}
 
 	constexpr uint16_t max_trx_id = PAGE_HEADER + PAGE_MAX_TRX_ID;
-	if (dict_index_is_sec_or_ibuf(index)) {
-		/* In secondary indexes and the change buffer,
+	if (!index->is_primary()) {
+		/* In secondary indexes,
 		PAGE_MAX_TRX_ID can be reset on the root page, because
 		the field only matters on leaf pages, and the root no
 		longer is a leaf page. (Older versions of InnoDB did
@@ -1952,16 +1794,8 @@ btr_root_raise_and_insert(
 
 	/* Build the node pointer (= node key and page address) for the
 	child */
-	if (dict_index_is_spatial(index)) {
-		rtr_mbr_t		new_mbr;
-
-		rtr_page_cal_mbr(index, new_block, &new_mbr, *heap);
-		node_ptr = rtr_index_build_node_ptr(
-			index, &new_mbr, rec, new_page_no, *heap);
-	} else {
-		node_ptr = dict_index_build_node_ptr(
-			index, rec, new_page_no, *heap, level);
-	}
+	node_ptr = dict_index_build_node_ptr(index, rec, new_page_no, *heap,
+					     level);
 	/* The node pointer must be marked as the predefined minimum record,
 	as there is no lower alphabetical limit to records in the leftmost
 	node of a level: */
@@ -1994,13 +1828,6 @@ btr_root_raise_and_insert(
 	to new_block at this point.  Thus, the data should fit. */
 	ut_a(node_ptr_rec);
 
-	/* We play safe and reset the free bits for the new page */
-
-	if (!dict_index_is_clust(index)
-	    && !index->table->is_temporary()) {
-		ibuf_reset_free_bits(new_block);
-	}
-
 	page_cursor->block = new_block;
 	page_cursor->index = index;
 
@@ -2479,11 +2306,11 @@ btr_attach_half_pages(
 	/* for consistency, both blocks should be locked, before change */
 	if (prev_page_no != FIL_NULL && direction == FSP_DOWN) {
 		prev_block = btr_block_get(*index, prev_page_no, RW_X_LATCH,
-					   !level, mtr);
+					   mtr);
 	}
 	if (next_page_no != FIL_NULL && direction != FSP_DOWN) {
 		next_block = btr_block_get(*index, next_page_no, RW_X_LATCH,
-					   !level, mtr);
+					   mtr);
 	}
 
 	/* Build the node pointer (= node key and page address) for the upper
@@ -2629,10 +2456,9 @@ btr_insert_into_right_sibling(
 	page_t*		next_page;
 	btr_cur_t	next_father_cursor;
 	rec_t*		rec = nullptr;
-	ulint		max_size;
 
 	next_block = btr_block_get(*cursor->index(), next_page_no, RW_X_LATCH,
-				   page_is_leaf(page), mtr);
+				   mtr);
 	if (UNIV_UNLIKELY(!next_block)) {
 		return nullptr;
 	}
@@ -2655,8 +2481,6 @@ btr_insert_into_right_sibling(
 		return nullptr;
 	}
 
-	max_size = page_get_max_insert_size_after_reorganize(next_page, 1);
-
 	/* Extends gap lock for the next page */
 	if (is_leaf && cursor->index()->has_locking()) {
 		lock_update_node_pointer(block, next_block);
@@ -2666,15 +2490,6 @@ btr_insert_into_right_sibling(
 				    n_ext, mtr);
 
 	if (!rec) {
-		if (is_leaf
-		    && next_block->page.zip.ssize
-		    && !dict_index_is_clust(cursor->index())
-		    && !cursor->index()->table->is_temporary()) {
-			/* Reset the IBUF_BITMAP_FREE bits, because
-			page_cur_tuple_insert() will have attempted page
-			reorganize before failing. */
-			ibuf_reset_free_bits(next_block);
-		}
 		return nullptr;
 	}
 
@@ -2712,34 +2527,12 @@ btr_insert_into_right_sibling(
 	}
 
 	ut_ad(rec_offs_validate(rec, cursor->index(), *offsets));
-
-	if (is_leaf
-	    && !dict_index_is_clust(cursor->index())
-	    && !cursor->index()->table->is_temporary()) {
-		/* Update the free bits of the B-tree page in the
-		insert buffer bitmap. */
-
-		if (next_block->page.zip.ssize) {
-			ibuf_update_free_bits_zip(next_block, mtr);
-		} else {
-			ibuf_update_free_bits_if_full(
-				next_block, max_size,
-				rec_offs_size(*offsets) + PAGE_DIR_SLOT_SIZE);
-		}
-	}
-
 	return(rec);
 }
 
 /*************************************************************//**
 Moves record list end to another page. Moved records include
 split_rec.
-
-IMPORTANT: The caller will have to update IBUF_BITMAP_FREE
-if new_block is a compressed leaf page in a secondary index.
-This has to be done either within the same mini-transaction,
-or by invoking ibuf_reset_free_bits() before mtr_commit().
-
 @return error code */
 static
 dberr_t
@@ -2795,12 +2588,6 @@ page_move_rec_list_end(
 /*************************************************************//**
 Moves record list start to another page. Moved records do not include
 split_rec.
-
-IMPORTANT: The caller will have to update IBUF_BITMAP_FREE
-if new_block is a compressed leaf page in a secondary index.
-This has to be done either within the same mini-transaction,
-or by invoking ibuf_reset_free_bits() before mtr_commit().
-
 @return error code */
 static
 dberr_t
@@ -2858,12 +2645,7 @@ btr_page_split_and_insert(
 
 	ut_ad(*err == DB_SUCCESS);
 	ut_ad(dtuple_check_typed(tuple));
-
-	if (cursor->index()->is_spatial()) {
-		/* Split rtree page and update parent */
-		return rtr_page_split_and_insert(flags, cursor, offsets, heap,
-						 tuple, n_ext, mtr, err);
-	}
+	ut_ad(!cursor->index()->is_spatial());
 
 	if (!*heap) {
 		*heap = mem_heap_create(1024);
@@ -3228,13 +3010,6 @@ insert_empty:
 		/* The insert did not fit on the page: loop back to the
 		start of the function for a new split */
 insert_failed:
-		/* We play safe and reset the free bits for new_page */
-		if (!dict_index_is_clust(page_cursor->index)
-		    && !page_cursor->index->table->is_temporary()) {
-			ibuf_reset_free_bits(new_block);
-			ibuf_reset_free_bits(block);
-		}
-
 		n_iterations++;
 		ut_ad(n_iterations < 2
 		      || buf_block_get_page_zip(insert_block));
@@ -3244,17 +3019,6 @@ insert_failed:
 	}
 
 func_exit:
-	/* Insert fit on the page: update the free bits for the
-	left and right pages in the same mtr */
-
-	if (!dict_index_is_clust(page_cursor->index)
-	    && !page_cursor->index->table->is_temporary()
-	    && page_is_leaf(page)) {
-
-		ibuf_update_free_bits_for_two_pages_low(
-			left_block, right_block, mtr);
-	}
-
 	MONITOR_INC(MONITOR_INDEX_SPLIT);
 
 	ut_ad(page_validate(buf_block_get_frame(left_block),
@@ -3287,8 +3051,7 @@ dberr_t btr_level_list_remove(const buf_block_t& block,
 
 	if (prev_page_no != FIL_NULL) {
 		buf_block_t*	prev_block = btr_block_get(
-			index, prev_page_no, RW_X_LATCH, page_is_leaf(page),
-			mtr, &err);
+			index, prev_page_no, RW_X_LATCH, mtr, &err);
 		if (UNIV_UNLIKELY(!prev_block)) {
 			return err;
 		}
@@ -3303,8 +3066,7 @@ dberr_t btr_level_list_remove(const buf_block_t& block,
 
 	if (next_page_no != FIL_NULL) {
 		buf_block_t*	next_block = btr_block_get(
-			index, next_page_no, RW_X_LATCH, page_is_leaf(page),
-			mtr, &err);
+			index, next_page_no, RW_X_LATCH, mtr, &err);
 
 		if (UNIV_UNLIKELY(!next_block)) {
 			return err;
@@ -3332,6 +3094,7 @@ btr_lift_page_up(
 				must not be empty: use
 				btr_discard_only_page_on_level if the last
 				record from the page should be removed */
+	que_thr_t*	thr,	/*!< in/out: query thread */
 	mtr_t*		mtr,	/*!< in/out: mini-transaction */
 	dberr_t*	err)	/*!< out: error code */
 {
@@ -3366,7 +3129,8 @@ btr_lift_page_up(
 
 		if (index->is_spatial()) {
 			offsets = rtr_page_get_father_block(
-				nullptr, heap, mtr, nullptr, &cursor);
+				nullptr, heap, nullptr, &cursor,
+				thr, mtr);
 		} else {
 			offsets = btr_page_get_father_block(offsets, heap,
 							    mtr, &cursor);
@@ -3387,7 +3151,8 @@ btr_lift_page_up(
 
 			if (index->is_spatial()) {
 				offsets = rtr_page_get_father_block(
-					nullptr, heap, mtr, nullptr, &cursor);
+					nullptr, heap, nullptr, &cursor, thr,
+					mtr);
 			} else {
 				offsets = btr_page_get_father_block(offsets,
 								    heap,
@@ -3518,13 +3283,8 @@ copied:
 	/* Free the file page */
 	btr_page_free(index, block, mtr);
 
-	/* We play it safe and reset the free bits for the father */
-	if (!dict_index_is_clust(index)
-	    && !index->table->is_temporary()) {
-		ibuf_reset_free_bits(father_block);
-	}
 	ut_ad(page_validate(father_block->page.frame, index));
-	ut_ad(btr_check_node_ptr(index, father_block, mtr));
+	ut_ad(btr_check_node_ptr(index, father_block, thr, mtr));
 
 	return(lift_father_up ? block_orig : father_block);
 }
@@ -3591,8 +3351,10 @@ btr_compress(
 	father_cursor.page_cur.block = block;
 
 	if (index->is_spatial()) {
+		ut_ad(cursor->rtr_info);
 		offsets = rtr_page_get_father_block(
-			NULL, heap, mtr, cursor, &father_cursor);
+			nullptr, heap, cursor, &father_cursor,
+			cursor->rtr_info->thr, mtr);
 		ut_ad(cursor->page_cur.block->page.id() == block->page.id());
 		rec_t*  my_rec = father_cursor.page_cur.rec;
 
@@ -3602,10 +3364,10 @@ btr_compress(
 			ib::info() << "father positioned on page "
 				<< page_no << "instead of "
 				<< block->page.id().page_no();
-			offsets = btr_page_get_father_block(
-				NULL, heap, mtr, &father_cursor);
+			goto get_offsets;
 		}
 	} else {
+get_offsets:
 		offsets = btr_page_get_father_block(
 			NULL, heap, mtr, &father_cursor);
 	}
@@ -3615,14 +3377,7 @@ btr_compress(
 		if (UNIV_UNLIKELY(!nth_rec || nth_rec == ULINT_UNDEFINED)) {
 		corrupted:
 			err = DB_CORRUPTION;
-		err_exit:
-			/* We play it safe and reset the free bits. */
-			if (merge_block && merge_block->zip_size()
-			    && page_is_leaf(merge_block->page.frame)
-			    && !index->is_clust()) {
-				ibuf_reset_free_bits(merge_block);
-			}
-			goto func_exit;
+			goto err_exit;
 		}
 	}
 
@@ -3630,7 +3385,10 @@ btr_compress(
 		/* The page is the only one on the level, lift the records
 		to the father */
 
-		merge_block = btr_lift_page_up(index, block, mtr, &err);
+		merge_block = btr_lift_page_up(index, block,
+					       cursor->rtr_info
+					       ? cursor->rtr_info->thr
+					       : nullptr, mtr, &err);
 success:
 		if (adjust) {
 			ut_ad(nth_rec > 0);
@@ -3645,7 +3403,7 @@ success:
 		}
 
 		MONITOR_INC(MONITOR_INDEX_MERGE_SUCCESSFUL);
-func_exit:
+err_exit:
 		mem_heap_free(heap);
 		DBUG_RETURN(err);
 	}
@@ -3945,49 +3703,6 @@ cannot_merge:
 		}
 	}
 
-	if (!dict_index_is_clust(index)
-	    && !index->table->is_temporary()
-	    && page_is_leaf(merge_page)) {
-		/* Update the free bits of the B-tree page in the
-		insert buffer bitmap.  This has to be done in a
-		separate mini-transaction that is committed before the
-		main mini-transaction.  We cannot update the insert
-		buffer bitmap in this mini-transaction, because
-		btr_compress() can be invoked recursively without
-		committing the mini-transaction in between.  Since
-		insert buffer bitmap pages have a lower rank than
-		B-tree pages, we must not access other pages in the
-		same mini-transaction after accessing an insert buffer
-		bitmap page. */
-
-		/* The free bits in the insert buffer bitmap must
-		never exceed the free space on a page.  It is safe to
-		decrement or reset the bits in the bitmap in a
-		mini-transaction that is committed before the
-		mini-transaction that affects the free space. */
-
-		/* It is unsafe to increment the bits in a separately
-		committed mini-transaction, because in crash recovery,
-		the free bits could momentarily be set too high. */
-
-		if (merge_block->zip_size()) {
-			/* Because the free bits may be incremented
-			and we cannot update the insert buffer bitmap
-			in the same mini-transaction, the only safe
-			thing we can do here is the pessimistic
-			approach: reset the free bits. */
-			ibuf_reset_free_bits(merge_block);
-		} else {
-			/* On uncompressed pages, the free bits will
-			never increase here.  Thus, it is safe to
-			write the bits accurately in a separate
-			mini-transaction. */
-			ibuf_update_free_bits_if_full(merge_block,
-						      srv_page_size,
-						      ULINT_UNDEFINED);
-		}
-	}
-
 	ut_ad(page_validate(merge_page, index));
 #ifdef UNIV_ZIP_DEBUG
 	ut_a(!merge_page_zip || page_zip_validate(merge_page_zip, merge_page,
@@ -4002,7 +3717,10 @@ cannot_merge:
 	err = btr_page_free(index, block, mtr);
         if (err == DB_SUCCESS) {
 		ut_ad(leftmost_child
-		      || btr_check_node_ptr(index, merge_block, mtr));
+		      || btr_check_node_ptr(index, merge_block,
+					    cursor->rtr_info
+					    ? cursor->rtr_info->thr
+					    : nullptr, mtr));
 		goto success;
         } else {
 		goto err_exit;
@@ -4019,11 +3737,13 @@ static
 void
 btr_discard_only_page_on_level(
 /*===========================*/
-	dict_index_t*	index,	/*!< in: index tree */
-	buf_block_t*	block,	/*!< in: page which is the only on its level */
+	btr_cur_t*	cur,	/*!< in: cursor on a page which is the
+				only on its level */
 	mtr_t*		mtr)	/*!< in: mtr */
 {
-	ulint		page_level = 0;
+	dict_index_t* index = cur->index();
+	buf_block_t* block = btr_cur_get_block(cur);
+	ulint page_level = 0;
 
 	ut_ad(!index->is_dummy);
 
@@ -4054,7 +3774,8 @@ btr_discard_only_page_on_level(
 		if (index->is_spatial()) {
 			/* Check any concurrent search having this page */
 			rtr_check_discard_page(index, NULL, block);
-			if (!rtr_page_get_father(mtr, nullptr, &cursor)) {
+			if (!rtr_page_get_father(mtr, nullptr, &cursor,
+						 cur->rtr_info->thr)) {
 				return;
 			}
 		} else {
@@ -4120,9 +3841,6 @@ btr_discard_only_page_on_level(
 			index->clear_instant_add();
 		}
 	} else if (!index->table->is_temporary()) {
-		/* We play it safe and reset the free bits for the root */
-		ibuf_reset_free_bits(block);
-
 		ut_a(max_trx_id);
 		page_set_max_trx_id(block,
 				    buf_block_get_page_zip(block),
@@ -4159,7 +3877,8 @@ btr_discard_page(
 	MONITOR_INC(MONITOR_INDEX_DISCARD);
 
 	if (index->is_spatial()
-	    ? !rtr_page_get_father(mtr, cursor, &parent_cursor)
+	    ? !rtr_page_get_father(mtr, cursor, &parent_cursor,
+				   cursor->rtr_info->thr)
 	    : !btr_page_get_father(mtr, &parent_cursor)) {
 		return DB_CORRUPTION;
 	}
@@ -4173,7 +3892,7 @@ btr_discard_page(
 	if (left_page_no != FIL_NULL) {
 		dberr_t err;
 		merge_block = btr_block_get(*index, left_page_no, RW_X_LATCH,
-					    true, mtr, &err);
+					    mtr, &err);
 		if (UNIV_UNLIKELY(!merge_block)) {
 			return err;
 		}
@@ -4194,7 +3913,7 @@ btr_discard_page(
 	} else if (right_page_no != FIL_NULL) {
 		dberr_t err;
 		merge_block = btr_block_get(*index, right_page_no, RW_X_LATCH,
-					    true, mtr, &err);
+					    mtr, &err);
 		if (UNIV_UNLIKELY(!merge_block)) {
 			return err;
 		}
@@ -4220,7 +3939,7 @@ btr_discard_page(
 			return DB_CORRUPTION;
 		}
 	} else {
-		btr_discard_only_page_on_level(index, block, mtr);
+		btr_discard_only_page_on_level(cursor, mtr);
 		return DB_SUCCESS;
 	}
 
@@ -4278,14 +3997,20 @@ btr_discard_page(
 		If the merge_block's parent block is not same,
 		we cannot use btr_check_node_ptr() */
 		ut_ad(parent_is_different
-		      || btr_check_node_ptr(index, merge_block, mtr));
+		      || btr_check_node_ptr(index, merge_block,
+					    cursor->rtr_info
+					    ? cursor->rtr_info->thr
+					    : nullptr, mtr));
 
 		if (btr_cur_get_block(&parent_cursor)->page.id().page_no()
 		    == index->page
 		    && !page_has_siblings(btr_cur_get_page(&parent_cursor))
 		    && page_get_n_recs(btr_cur_get_page(&parent_cursor))
 		    == 1) {
-			btr_lift_page_up(index, merge_block, mtr, &err);
+			btr_lift_page_up(index, merge_block,
+					 cursor->rtr_info
+					 ? cursor->rtr_info->thr
+					 : nullptr, mtr, &err);
 		}
 	}
 
@@ -4304,13 +4029,6 @@ btr_print_size(
 	fseg_header_t*	seg;
 	mtr_t		mtr;
 
-	if (dict_index_is_ibuf(index)) {
-		fputs("Sorry, cannot print info of an ibuf tree:"
-		      " use ibuf functions\n", stderr);
-
-		return;
-	}
-
 	mtr_start(&mtr);
 
 	root = btr_root_get(index, &mtr);
@@ -4320,13 +4038,10 @@ btr_print_size(
 	fputs("INFO OF THE NON-LEAF PAGE SEGMENT\n", stderr);
 	fseg_print(seg, &mtr);
 
-	if (!dict_index_is_ibuf(index)) {
-
-		seg = root + PAGE_HEADER + PAGE_BTR_SEG_LEAF;
+	seg = root + PAGE_HEADER + PAGE_BTR_SEG_LEAF;
 
-		fputs("INFO OF THE LEAF PAGE SEGMENT\n", stderr);
-		fseg_print(seg, &mtr);
-	}
+	fputs("INFO OF THE LEAF PAGE SEGMENT\n", stderr);
+	fseg_print(seg, &mtr);
 
 	mtr_commit(&mtr);
 }
@@ -4437,6 +4152,7 @@ btr_check_node_ptr(
 /*===============*/
 	dict_index_t*	index,	/*!< in: index tree */
 	buf_block_t*	block,	/*!< in: index page */
+	que_thr_t*	thr,	/*!< in/out: query thread */
 	mtr_t*		mtr)	/*!< in: mtr */
 {
 	mem_heap_t*	heap;
@@ -4458,8 +4174,8 @@ btr_check_node_ptr(
 	heap = mem_heap_create(256);
 
 	if (dict_index_is_spatial(index)) {
-		offsets = rtr_page_get_father_block(NULL, heap, mtr,
-						    NULL, &cursor);
+		offsets = rtr_page_get_father_block(NULL, heap,
+						    NULL, &cursor, thr, mtr);
 	} else {
 		offsets = btr_page_get_father_block(NULL, heap, mtr, &cursor);
 	}
@@ -4532,14 +4248,6 @@ btr_index_rec_validate(
 
 	ut_ad(index->n_core_fields);
 
-	if (index->is_ibuf()) {
-		/* The insert buffer index tree can contain records from any
-		other index: we cannot check the number of fields or
-		their length */
-
-		return(TRUE);
-	}
-
 #ifdef VIRTUAL_INDEX_DEBUG
 	if (dict_index_has_virtual(index)) {
 		fprintf(stderr, "index name is %s\n", index->name());
@@ -4882,8 +4590,7 @@ corrupted:
 
 				savepoint2 = mtr_set_savepoint(&mtr);
 				block = btr_block_get(*index, left_page_no,
-						      RW_SX_LATCH, false,
-						      &mtr, &err);
+						      RW_SX_LATCH, &mtr, &err);
 				if (!block) {
 					goto invalid_page;
 				}
@@ -4961,7 +4668,7 @@ func_exit:
 		savepoint = mtr_set_savepoint(&mtr);
 
 		right_block = btr_block_get(*index, right_page_no, RW_SX_LATCH,
-					    !level, &mtr, &err);
+					    &mtr, &err);
 		if (!right_block) {
 			btr_validate_report1(index, level, block);
 			fputs("InnoDB: broken FIL_PAGE_NEXT link\n", stderr);
@@ -5158,15 +4865,13 @@ broken_links:
 				if (parent_right_page_no != FIL_NULL) {
 					btr_block_get(*index,
 						      parent_right_page_no,
-						      RW_SX_LATCH, false,
-						      &mtr);
+						      RW_SX_LATCH, &mtr);
 				}
 
 				right_block = btr_block_get(*index,
 							    right_page_no,
 							    RW_SX_LATCH,
-							    !level, &mtr,
-							    &err);
+							    &mtr, &err);
 				if (!right_block) {
 					btr_validate_report1(index, level,
 							     block);
@@ -5252,17 +4957,16 @@ node_ptr_fails:
 				if (parent_right_page_no != FIL_NULL) {
 					btr_block_get(*index,
 						      parent_right_page_no,
-						      RW_SX_LATCH, false,
-						      &mtr);
+						      RW_SX_LATCH, &mtr);
 				}
 			} else if (parent_page_no != FIL_NULL) {
 				btr_block_get(*index, parent_page_no,
-					      RW_SX_LATCH, false, &mtr);
+					      RW_SX_LATCH, &mtr);
 			}
 		}
 
 		block = btr_block_get(*index, right_page_no, RW_SX_LATCH,
-				      !level, &mtr, &err);
+				      &mtr, &err);
 		goto loop;
 	}
 
@@ -5334,8 +5038,7 @@ error:
 	index = btr_cur_get_index(cursor);
 	page = btr_cur_get_page(cursor);
 
-	mblock = btr_block_get(*index, page_no, RW_X_LATCH, page_is_leaf(page),
-			       mtr);
+	mblock = btr_block_get(*index, page_no, RW_X_LATCH, mtr);
 	if (!mblock) {
 		goto error;
 	}
diff --git a/storage/innobase/btr/btr0bulk.cc b/storage/innobase/btr/btr0bulk.cc
index 013cd13102c..3c5b4b293f2 100644
--- a/storage/innobase/btr/btr0bulk.cc
+++ b/storage/innobase/btr/btr0bulk.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2014, 2019, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -28,7 +28,6 @@ Created 03/11/2014 Shaohua Wang
 #include "btr0btr.h"
 #include "btr0cur.h"
 #include "btr0pcur.h"
-#include "ibuf0ibuf.h"
 #include "page0page.h"
 #include "trx0trx.h"
 
@@ -107,7 +106,7 @@ oom:
 		}
 	} else {
 		new_block = btr_block_get(*m_index, m_page_no, RW_X_LATCH,
-					  false, &m_mtr);
+					  &m_mtr);
 		if (!new_block) {
 			m_mtr.commit();
 			return(DB_CORRUPTION);
@@ -122,7 +121,7 @@ oom:
 
 	m_page_zip = buf_block_get_page_zip(new_block);
 
-	if (!m_level && dict_index_is_sec_or_ibuf(m_index)) {
+	if (!m_level && !m_index->is_primary()) {
 		page_update_max_trx_id(new_block, m_page_zip, m_trx_id,
 				       &m_mtr);
 	}
@@ -563,9 +562,6 @@ inline void PageBulk::finish()
 void PageBulk::commit(bool success)
 {
   finish();
-  if (success && !m_index->is_clust() && page_is_leaf(m_page))
-    ibuf_set_bitmap_for_bulk_load(m_block, &m_mtr,
-                                  innobase_fill_factor == 100);
   m_mtr.commit();
 }
 
@@ -1194,7 +1190,7 @@ BtrBulk::finish(dberr_t	err)
 
 		ut_ad(last_page_no != FIL_NULL);
 		last_block = btr_block_get(*m_index, last_page_no, RW_X_LATCH,
-					   false, &mtr);
+					   &mtr);
 		if (!last_block) {
 			err = DB_CORRUPTION;
 err_exit:
diff --git a/storage/innobase/btr/btr0cur.cc b/storage/innobase/btr/btr0cur.cc
index 2f237bb5957..a4260c7f111 100644
--- a/storage/innobase/btr/btr0cur.cc
+++ b/storage/innobase/btr/btr0cur.cc
@@ -3,7 +3,7 @@
 Copyright (c) 1994, 2019, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2008, Google Inc.
 Copyright (c) 2012, Facebook Inc.
-Copyright (c) 2015, 2022, MariaDB Corporation.
+Copyright (c) 2015, 2023, MariaDB Corporation.
 
 Portions of this file contain modifications contributed and copyrighted by
 Google, Inc. Those modifications are gratefully acknowledged and are described
@@ -61,7 +61,6 @@ Created 10/16/1994 Heikki Tuuri
 #include "que0que.h"
 #include "row0row.h"
 #include "srv0srv.h"
-#include "ibuf0ibuf.h"
 #include "lock0lock.h"
 #include "zlib.h"
 #include "srv0start.h"
@@ -73,15 +72,6 @@ Created 10/16/1994 Heikki Tuuri
 #endif /* WITH_WSREP */
 #include "log.h"
 
-/** Buffered B-tree operation types, introduced as part of delete buffering. */
-enum btr_op_t {
-	BTR_NO_OP = 0,			/*!< Not buffered */
-	BTR_INSERT_OP,			/*!< Insert, do not ignore UNIQUE */
-	BTR_INSERT_IGNORE_UNIQUE_OP,	/*!< Insert, ignoring UNIQUE */
-	BTR_DELETE_OP,			/*!< Purge a delete-marked record */
-	BTR_DELMARK_OP			/*!< Mark a record for deletion */
-};
-
 /** Modification types for the B-tree operation.
     Note that the order must be DELETE, BOTH, INSERT !!
  */
@@ -259,7 +249,7 @@ latch_block:
 		if (left_page_no != FIL_NULL) {
 			buf_block_t *b = btr_block_get(
 				*cursor->index(), left_page_no, RW_X_LATCH,
-				true, mtr);
+				mtr);
 
 			if (latch_leaves) {
 				latch_leaves->savepoints[0] = save;
@@ -300,7 +290,7 @@ latch_block:
 
 			buf_block_t* b = btr_block_get(
 				*cursor->index(), right_page_no, RW_X_LATCH,
-				true, mtr);
+				mtr);
 			if (latch_leaves) {
 				latch_leaves->savepoints[2] = save;
 				latch_leaves->blocks[2] = b;
@@ -331,8 +321,7 @@ latch_block:
 		if (left_page_no != FIL_NULL) {
 			save = mtr->get_savepoint();
 			cursor->left_block = btr_block_get(
-				*cursor->index(), left_page_no,
-				mode, true, mtr);
+				*cursor->index(), left_page_no, mode, mtr);
 			if (latch_leaves) {
 				latch_leaves->savepoints[0] = save;
 				latch_leaves->blocks[0] = cursor->left_block;
@@ -341,7 +330,8 @@ latch_block:
 
 		goto latch_block;
 	case BTR_CONT_MODIFY_TREE:
-		ut_ad(cursor->index()->is_spatial());
+		ut_ad(cursor->index()->is_dummy
+		      || cursor->index()->is_spatial());
 		return;
 	}
 
@@ -758,7 +748,7 @@ btr_cur_optimistic_latch_leaves(
 		return(buf_page_optimistic_get(*latch_mode, block,
 				modify_clock, mtr));
 	case BTR_SEARCH_PREV: /* btr_pcur_move_backward_from_page() */
-	case BTR_MODIFY_PREV: /* Ditto, or ibuf_insert() */
+	case BTR_MODIFY_PREV: /* Ditto */
 		uint32_t curr_page_no, left_page_no;
 		{
 			transactional_shared_lock_guard<block_lock> g{
@@ -1063,20 +1053,6 @@ btr_cur_need_opposite_intention(
 @return maximum size of a node pointer record in bytes */
 static ulint btr_node_ptr_max_size(const dict_index_t* index)
 {
-	if (dict_index_is_ibuf(index)) {
-		/* cannot estimate accurately */
-		/* This is universal index for change buffer.
-		The max size of the entry is about max key length * 2.
-		(index key + primary key to be inserted to the index)
-		(The max key length is UNIV_PAGE_SIZE / 16 * 3 at
-		 ha_innobase::max_supported_key_length(),
-		 considering MAX_KEY_LENGTH = 3072 at MySQL imposes
-		 the 3500 historical InnoDB value for 16K page size case.)
-		For the universal index, node_ptr contains most of the entry.
-		And 512 is enough to contain ibuf columns and meta-data */
-		return srv_page_size / 8 * 3 + 512;
-	}
-
 	/* Each record has page_no, length of page_no and header. */
 	ulint comp = dict_table_is_comp(index->table);
 	ulint rec_max_size = comp
@@ -1245,10 +1221,8 @@ dberr_t btr_cur_search_to_nth_level(ulint level,
 	ulint		rw_latch;
 	page_cur_mode_t	page_mode;
 	page_cur_mode_t	search_mode = PAGE_CUR_UNSUPP;
-	ulint		buf_mode;
 	ulint		node_ptr_max_size = srv_page_size / 2;
 	page_cur_t*	page_cursor;
-	btr_op_t	btr_op;
 	ulint		root_height = 0; /* remove warning */
 
 	btr_intention_t	lock_intention;
@@ -1287,7 +1261,6 @@ dberr_t btr_cur_search_to_nth_level(ulint level,
 	ut_ad(level == 0 || mode == PAGE_CUR_LE
 	      || RTREE_SEARCH_MODE(mode));
 	ut_ad(dict_index_check_search_tuple(index, tuple));
-	ut_ad(!dict_index_is_ibuf(index) || ibuf_inside(mtr));
 	ut_ad(dtuple_check_typed(tuple));
 	ut_ad(!(index->type & DICT_FTS));
 	ut_ad(index->page != FIL_NULL);
@@ -1308,36 +1281,6 @@ dberr_t btr_cur_search_to_nth_level(ulint level,
 	      || mtr->memo_contains_flagged(&index->lock, MTR_MEMO_S_LOCK
 					    | MTR_MEMO_SX_LOCK));
 
-	/* These flags are mutually exclusive, they are lumped together
-	with the latch mode for historical reasons. It's possible for
-	none of the flags to be set. */
-	switch (UNIV_EXPECT(latch_mode & BTR_DELETE, 0)) {
-	default:
-		btr_op = BTR_NO_OP;
-		break;
-	case BTR_INSERT:
-		btr_op = (latch_mode & BTR_IGNORE_SEC_UNIQUE)
-			? BTR_INSERT_IGNORE_UNIQUE_OP
-			: BTR_INSERT_OP;
-		break;
-	case BTR_DELETE:
-		btr_op = BTR_DELETE_OP;
-		ut_a(cursor->purge_node);
-		break;
-	case BTR_DELETE_MARK:
-		btr_op = BTR_DELMARK_OP;
-		break;
-	}
-
-	/* Operations on the insert buffer tree cannot be buffered. */
-	ut_ad(btr_op == BTR_NO_OP || !dict_index_is_ibuf(index));
-	/* Operations on the clustered index cannot be buffered. */
-	ut_ad(btr_op == BTR_NO_OP || !dict_index_is_clust(index));
-	/* Operations on the temporary table(indexes) cannot be buffered. */
-	ut_ad(btr_op == BTR_NO_OP || !index->table->is_temporary());
-	/* Operation on the spatial index cannot be buffered. */
-	ut_ad(btr_op == BTR_NO_OP || !dict_index_is_spatial(index));
-
 	lock_intention = btr_cur_get_and_clear_intention(&latch_mode);
 
 	/* Turn the flags unrelated to the latch mode off. */
@@ -1512,7 +1455,6 @@ x_latch_index:
 	btr_latch_leaves_t latch_leaves = {{NULL, NULL, NULL}, {0, 0, 0}};
 
 search_loop:
-	buf_mode = BUF_GET;
 	rw_latch = RW_NO_LATCH;
 	rtree_parent_modified = false;
 
@@ -1534,108 +1476,16 @@ search_loop:
 		}
 	} else if (latch_mode <= BTR_MODIFY_LEAF) {
 		rw_latch = latch_mode;
-
-		if (btr_op != BTR_NO_OP
-		    && ibuf_should_try(index, btr_op != BTR_INSERT_OP)) {
-
-			/* Try to buffer the operation if the leaf
-			page is not in the buffer pool. */
-
-			buf_mode = btr_op == BTR_DELETE_OP
-				? BUF_GET_IF_IN_POOL_OR_WATCH
-				: BUF_GET_IF_IN_POOL;
-		}
 	}
 
-retry_page_get:
 	ut_ad(n_blocks < BTR_MAX_LEVELS);
 	tree_savepoints[n_blocks] = mtr_set_savepoint(mtr);
 	dberr_t err;
 	block = buf_page_get_gen(page_id, zip_size, rw_latch, guess,
-				 buf_mode, mtr, &err,
-				 height == 0 && !index->is_clust());
-	if (!block) {
-		switch (err) {
-		case DB_SUCCESS:
-			/* change buffering */
-			break;
-		case DB_DECRYPTION_FAILED:
-			btr_decryption_failed(*index);
-			/* fall through */
-		default:
-			goto func_exit;
-		}
-
-		/* This must be a search to perform an insert/delete
-		mark/ delete; try using the insert/delete buffer */
-
-		ut_ad(height == 0);
-		ut_ad(cursor->thr);
-
-		switch (btr_op) {
-		default:
-			MY_ASSERT_UNREACHABLE();
-			break;
-		case BTR_INSERT_OP:
-		case BTR_INSERT_IGNORE_UNIQUE_OP:
-			ut_ad(buf_mode == BUF_GET_IF_IN_POOL);
-
-			if (ibuf_insert(IBUF_OP_INSERT, tuple, index,
-					page_id, zip_size, cursor->thr)) {
-
-				cursor->flag = BTR_CUR_INSERT_TO_IBUF;
-
-				goto func_exit;
-			}
-			break;
-
-		case BTR_DELMARK_OP:
-			ut_ad(buf_mode == BUF_GET_IF_IN_POOL);
-
-			if (ibuf_insert(IBUF_OP_DELETE_MARK, tuple,
-					index, page_id, zip_size,
-					cursor->thr)) {
-
-				cursor->flag = BTR_CUR_DEL_MARK_IBUF;
+				 BUF_GET, mtr, &err);
 
-				goto func_exit;
-			}
-
-			break;
-
-		case BTR_DELETE_OP:
-			ut_ad(buf_mode == BUF_GET_IF_IN_POOL_OR_WATCH);
-			ut_ad(index->is_btree());
-			auto& chain = buf_pool.page_hash.cell_get(
-				page_id.fold());
-
-			if (!row_purge_poss_sec(cursor->purge_node,
-						index, tuple)) {
-
-				/* The record cannot be purged yet. */
-				cursor->flag = BTR_CUR_DELETE_REF;
-			} else if (ibuf_insert(IBUF_OP_DELETE, tuple,
-					       index, page_id, zip_size,
-					       cursor->thr)) {
-
-				/* The purge was buffered. */
-				cursor->flag = BTR_CUR_DELETE_IBUF;
-			} else {
-				/* The purge could not be buffered. */
-				buf_pool.watch_unset(page_id, chain);
-				break;
-			}
-
-			buf_pool.watch_unset(page_id, chain);
-			goto func_exit;
-		}
-
-		/* Insert to the insert/delete buffer did not succeed, we
-		must read the page from disk. */
-
-		buf_mode = BUF_GET;
-
-		goto retry_page_get;
+	if (!block) {
+		goto func_exit;
 	}
 
 	tree_blocks[n_blocks] = block;
@@ -1658,7 +1508,7 @@ retry_page_get:
 				= mtr_set_savepoint(mtr);
 			buf_block_t* get_block = buf_page_get_gen(
 				page_id_t(page_id.space(), left_page_no),
-				zip_size, rw_latch, NULL, buf_mode,
+				zip_size, rw_latch, NULL, BUF_GET,
 				mtr, &err);
 			if (!get_block) {
 				if (err == DB_DECRYPTION_FAILED) {
@@ -1729,7 +1579,6 @@ retry_page_get:
 			}
 
 			/* Save the MBR */
-			cursor->rtr_info->thr = cursor->thr;
 			rtr_get_mbr_from_tuple(tuple, &cursor->rtr_info->mbr);
 		}
 
@@ -1902,15 +1751,16 @@ retry_page_get:
 
 	/* Add Predicate lock if it is serializable isolation
 	and only if it is in the search case */
-	if (dict_index_is_spatial(index)
+	if (index->is_spatial()
 	    && cursor->rtr_info->need_prdt_lock
+	    && mode >= PAGE_CUR_CONTAIN
 	    && mode != PAGE_CUR_RTREE_INSERT
-	    && mode != PAGE_CUR_RTREE_LOCATE
-	    && mode >= PAGE_CUR_CONTAIN) {
+	    && mode != PAGE_CUR_RTREE_LOCATE) {
 		lock_prdt_t	prdt;
+		que_thr_t*	thr = cursor->rtr_info->thr;
 
 		{
-			trx_t* trx = thr_get_trx(cursor->thr);
+			trx_t* trx = thr_get_trx(thr);
 			TMLockTrxGuard g{TMLockTrxArgs(*trx)};
 			lock_init_prdt_from_mbr(
 				&prdt, &cursor->rtr_info->mbr, mode,
@@ -1922,7 +1772,7 @@ retry_page_get:
 		}
 
 		lock_prdt_lock(block, &prdt, index, LOCK_S,
-			       LOCK_PREDICATE, cursor->thr);
+			       LOCK_PREDICATE, thr);
 
 		if (rw_latch == RW_NO_LATCH && height != 0) {
 			block->page.lock.s_unlock();
@@ -2230,17 +2080,6 @@ need_opposite_intention:
 
 		n_blocks++;
 
-		if (UNIV_UNLIKELY(height == 0 && dict_index_is_ibuf(index))) {
-			/* We're doing a search on an ibuf tree and we're one
-			level above the leaf page. */
-
-			ut_ad(level == 0);
-
-			buf_mode = BUF_GET;
-			rw_latch = RW_NO_LATCH;
-			goto retry_page_get;
-		}
-
 		if (dict_index_is_spatial(index)
 		    && page_mode >= PAGE_CUR_CONTAIN
 		    && page_mode != PAGE_CUR_RTREE_INSERT) {
@@ -2311,7 +2150,7 @@ need_opposite_intention:
 			btr_block_get(
 				*index, page_id.page_no(),
 				latch_mode == BTR_CONT_MODIFY_TREE
-				? RW_X_LATCH : RW_SX_LATCH, false, mtr, &err);
+				? RW_X_LATCH : RW_SX_LATCH, mtr, &err);
 		} else {
 			ut_ad(mtr->memo_contains_flagged(block,
 							 upper_rw_latch));
@@ -2440,10 +2279,12 @@ dberr_t btr_cur_t::open_leaf(bool first, dict_index_t *index,
   rw_lock_type_t upper_rw_latch= RW_X_LATCH;
 
   switch (latch_mode) {
-  case BTR_CONT_MODIFY_TREE:
   case BTR_CONT_SEARCH_TREE:
-    abort();
-    break;
+    ut_ad("invalid mode" == 0);
+    /* fall through */
+  case BTR_CONT_MODIFY_TREE:
+    ut_ad(index->is_dummy);
+    /* fall through */
   case BTR_MODIFY_TREE:
     /* Most of delete-intended operations are purging. Free blocks
     and read IO bandwidth should be prioritized for them, when the
@@ -2489,9 +2330,7 @@ dberr_t btr_cur_t::open_leaf(bool first, dict_index_t *index,
     const rw_lock_type_t rw_latch= height && latch_mode != BTR_MODIFY_TREE
       ? upper_rw_latch
       : RW_NO_LATCH;
-    buf_block_t* block=
-      btr_block_get(*index, page, rw_latch, !height && !index->is_clust(), mtr,
-                    &err);
+    buf_block_t* block= btr_block_get(*index, page, rw_latch, mtr, &err);
 
     ut_ad(!block == (err != DB_SUCCESS));
 
@@ -2514,7 +2353,9 @@ dberr_t btr_cur_t::open_leaf(bool first, dict_index_t *index,
       /* We are in the root node */
       height= l;
       if (height);
-      else if (upper_rw_latch != root_leaf_rw_latch)
+      else if (upper_rw_latch != root_leaf_rw_latch &&
+               /* ibuf_upgrade() needs the following condition */
+               UNIV_LIKELY(root_leaf_rw_latch != RW_NO_LATCH))
       {
         /* We should retry to get the page, because the root page
         is latched with different level as a leaf page. */
@@ -2635,11 +2476,6 @@ be freed by reorganizing. Differs from btr_cur_optimistic_insert because
 no heuristics is applied to whether it pays to use CPU time for
 reorganizing the page or not.
 
-IMPORTANT: The caller will have to update IBUF_BITMAP_FREE
-if this is a compressed leaf page in a secondary index.
-This has to be done either within the same mini-transaction,
-or by invoking ibuf_reset_free_bits() before mtr_commit().
-
 @return pointer to inserted record if succeed, else NULL */
 static MY_ATTRIBUTE((nonnull, warn_unused_result))
 rec_t*
@@ -2808,9 +2644,6 @@ static void btr_cur_prefetch_siblings(const buf_block_t *block,
 {
   ut_ad(page_is_leaf(block->page.frame));
 
-  if (index->is_ibuf())
-    return;
-
   const page_t *page= block->page.frame;
   uint32_t prev= mach_read_from_4(my_assume_aligned<4>(page + FIL_PAGE_PREV));
   uint32_t next= mach_read_from_4(my_assume_aligned<4>(page + FIL_PAGE_NEXT));
@@ -3046,14 +2879,6 @@ fail_err:
 	if (*rec) {
 	} else if (block->page.zip.data) {
 		ut_ad(!index->table->is_temporary());
-		/* Reset the IBUF_BITMAP_FREE bits, because
-		page_cur_tuple_insert() will have attempted page
-		reorganize before failing. */
-		if (leaf
-		    && !dict_index_is_clust(index)) {
-			ibuf_reset_free_bits(block);
-		}
-
 		goto fail;
 	} else {
 		ut_ad(!reorg);
@@ -3094,34 +2919,6 @@ fail_err:
 		lock_update_insert(block, *rec);
 	}
 
-	if (leaf
-	    && !dict_index_is_clust(index)
-	    && !index->table->is_temporary()) {
-		/* Update the free bits of the B-tree page in the
-		insert buffer bitmap. */
-
-		/* The free bits in the insert buffer bitmap must
-		never exceed the free space on a page.  It is safe to
-		decrement or reset the bits in the bitmap in a
-		mini-transaction that is committed before the
-		mini-transaction that affects the free space. */
-
-		/* It is unsafe to increment the bits in a separately
-		committed mini-transaction, because in crash recovery,
-		the free bits could momentarily be set too high. */
-
-		if (block->page.zip.data) {
-			/* Update the bits in the same mini-transaction. */
-			ibuf_update_free_bits_zip(block, mtr);
-		} else {
-			/* Decrement the bits in a separate
-			mini-transaction. */
-			ibuf_update_free_bits_if_full(
-				block, max_size,
-				rec_size + PAGE_DIR_SLOT_SIZE);
-		}
-	}
-
 	*big_rec = big_rec_vec;
 
 	return(DB_SUCCESS);
@@ -3192,12 +2989,10 @@ btr_cur_pessimistic_insert(
 	the index tree, so that the insert will not fail because of
 	lack of space */
 
-	if (!index->is_ibuf()
-	    && (err = fsp_reserve_free_extents(&n_reserved, index->table->space,
-					       uint32_t(cursor->tree_height / 16
-							+ 3),
-					       FSP_NORMAL, mtr))
-	    != DB_SUCCESS) {
+	err = fsp_reserve_free_extents(&n_reserved, index->table->space,
+				       uint32_t(cursor->tree_height / 16 + 3),
+				       FSP_NORMAL, mtr);
+	if (err != DB_SUCCESS) {
 		return err;
 	}
 
@@ -3229,11 +3024,21 @@ btr_cur_pessimistic_insert(
 		}
 	}
 
-	*rec = index->page == btr_cur_get_block(cursor)->page.id().page_no()
-		? btr_root_raise_and_insert(flags, cursor, offsets, heap,
-					    entry, n_ext, mtr, &err)
-		: btr_page_split_and_insert(flags, cursor, offsets, heap,
-					    entry, n_ext, mtr, &err);
+	if (index->page == btr_cur_get_block(cursor)->page.id().page_no()) {
+		*rec = index->is_spatial()
+			? rtr_root_raise_and_insert(flags, cursor, offsets,
+						    heap, entry, n_ext, mtr,
+						    &err, thr)
+			: btr_root_raise_and_insert(flags, cursor, offsets,
+						    heap, entry, n_ext, mtr,
+						    &err);
+	} else if (index->is_spatial()) {
+		*rec = rtr_page_split_and_insert(flags, cursor, offsets, heap,
+						 entry, n_ext, mtr, &err, thr);
+	} else {
+		*rec = btr_page_split_and_insert(flags, cursor, offsets, heap,
+						 entry, n_ext, mtr, &err);
+	}
 
 	if (!*rec) {
 		goto func_exit;
@@ -3477,14 +3282,8 @@ static dberr_t btr_cur_upd_rec_sys(buf_block_t *block, rec_t *rec,
 See if there is enough place in the page modification log to log
 an update-in-place.
 
-@retval false if out of space; IBUF_BITMAP_FREE will be reset
-outside mtr if the page was recompressed
-@retval true if enough place;
-
-IMPORTANT: The caller will have to update IBUF_BITMAP_FREE if this is
-a secondary index leaf page. This has to be done either within the
-same mini-transaction, or by invoking ibuf_reset_free_bits() before
-mtr_commit(mtr). */
+@retval false if out of space
+@retval true if enough place */
 bool
 btr_cur_update_alloc_zip_func(
 /*==========================*/
@@ -3505,7 +3304,6 @@ btr_cur_update_alloc_zip_func(
 	const page_t*	page = page_cur_get_page(cursor);
 
 	ut_ad(page_zip == page_cur_get_page_zip(cursor));
-	ut_ad(!dict_index_is_ibuf(index));
 	ut_ad(rec_offs_validate(page_cur_get_rec(cursor), index, offsets));
 
 	if (page_zip_available(page_zip, dict_index_is_clust(index),
@@ -3529,26 +3327,8 @@ btr_cur_update_alloc_zip_func(
 		rec_offs_make_valid(page_cur_get_rec(cursor), index,
 				    page_is_leaf(page), offsets);
 
-		/* After recompressing a page, we must make sure that the free
-		bits in the insert buffer bitmap will not exceed the free
-		space on the page.  Because this function will not attempt
-		recompression unless page_zip_available() fails above, it is
-		safe to reset the free bits if page_zip_available() fails
-		again, below.  The free bits can safely be reset in a separate
-		mini-transaction.  If page_zip_available() succeeds below, we
-		can be sure that the btr_page_reorganize() above did not reduce
-		the free space available on the page. */
-
-		if (page_zip_available(page_zip, dict_index_is_clust(index),
-				       length, create)) {
-			return true;
-		}
-	}
-
-	if (!dict_index_is_clust(index)
-	    && !index->table->is_temporary()
-	    && page_is_leaf(page)) {
-		ibuf_reset_free_bits(page_cur_get_block(cursor));
+		return page_zip_available(page_zip, dict_index_is_clust(index),
+					  length, create);
 	}
 
 	return(false);
@@ -3697,7 +3477,7 @@ We assume here that the ordering fields of the record do not change.
 @return locking or undo log related error code, or
 @retval DB_SUCCESS on success
 @retval DB_ZIP_OVERFLOW if there is not enough space left
-on the compressed page (IBUF_BITMAP_FREE was reset outside mtr) */
+on a ROW_FORMAT=COMPRESSED page */
 dberr_t
 btr_cur_update_in_place(
 /*====================*/
@@ -3717,7 +3497,6 @@ btr_cur_update_in_place(
 				further pages */
 {
 	dict_index_t*	index;
-	dberr_t		err;
 	rec_t*		rec;
 	roll_ptr_t	roll_ptr	= 0;
 	ulint		was_delete_marked;
@@ -3725,17 +3504,14 @@ btr_cur_update_in_place(
 	ut_ad(page_is_leaf(cursor->page_cur.block->page.frame));
 	rec = btr_cur_get_rec(cursor);
 	index = cursor->index();
-	ut_ad(!index->is_ibuf());
 	ut_ad(rec_offs_validate(rec, index, offsets));
 	ut_ad(!!page_rec_is_comp(rec) == dict_table_is_comp(index->table));
 	ut_ad(trx_id > 0 || (flags & BTR_KEEP_SYS_FLAG)
 	      || index->table->is_temporary());
-	/* The insert buffer tree should never be updated in place. */
-	ut_ad(!dict_index_is_ibuf(index));
 	ut_ad(dict_index_is_online_ddl(index) == !!(flags & BTR_CREATE_FLAG)
-	      || dict_index_is_clust(index));
+	      || index->is_primary());
 	ut_ad(thr_get_trx(thr)->id == trx_id
-	      || (flags & ulint(~(BTR_KEEP_POS_FLAG | BTR_KEEP_IBUF_BITMAP)))
+	      || (flags & ulint(~BTR_KEEP_POS_FLAG))
 	      == (BTR_NO_UNDO_LOG_FLAG | BTR_NO_LOCKING_FLAG
 		  | BTR_CREATE_FLAG | BTR_KEEP_SYS_FLAG));
 	ut_ad(fil_page_index_page_check(btr_cur_get_page(cursor)));
@@ -3765,22 +3541,17 @@ btr_cur_update_in_place(
 	}
 
 	/* Do lock checking and undo logging */
-	err = btr_cur_upd_lock_and_undo(flags, cursor, offsets,
-					update, cmpl_info,
-					thr, mtr, &roll_ptr);
-	if (UNIV_UNLIKELY(err != DB_SUCCESS)) {
-		/* We may need to update the IBUF_BITMAP_FREE
-		bits after a reorganize that was done in
-		btr_cur_update_alloc_zip(). */
-		goto func_exit;
+	if (dberr_t err = btr_cur_upd_lock_and_undo(flags, cursor, offsets,
+						    update, cmpl_info,
+						    thr, mtr, &roll_ptr)) {
+		return err;
 	}
 
-	if (!(flags & BTR_KEEP_SYS_FLAG)) {
-		err = btr_cur_upd_rec_sys(block, rec, index, offsets,
-					  thr_get_trx(thr), roll_ptr, mtr);
-		if (UNIV_UNLIKELY(err != DB_SUCCESS)) {
-			goto func_exit;
-		}
+	if (flags & BTR_KEEP_SYS_FLAG) {
+	} else if (dberr_t err = btr_cur_upd_rec_sys(block, rec, index, offsets,
+						     thr_get_trx(thr),
+						     roll_ptr, mtr)) {
+		return err;
 	}
 
 	was_delete_marked = rec_get_deleted_flag(
@@ -3838,19 +3609,7 @@ btr_cur_update_in_place(
 		btr_cur_unmark_extern_fields(block, rec, index, offsets, mtr);
 	}
 
-	ut_ad(err == DB_SUCCESS);
-
-func_exit:
-	if (page_zip
-	    && !(flags & BTR_KEEP_IBUF_BITMAP)
-	    && !dict_index_is_clust(index)
-	    && page_is_leaf(buf_block_get_frame(block))) {
-		/* Update the free bits in the insert buffer. */
-		ut_ad(!index->table->is_temporary());
-		ibuf_update_free_bits_zip(block, mtr);
-	}
-
-	return(err);
+	return DB_SUCCESS;
 }
 
 /** Trim a metadata record during the rollback of instant ALTER TABLE.
@@ -3994,7 +3753,7 @@ fields of the record do not change.
 @retval DB_OVERFLOW if the updated record does not fit
 @retval DB_UNDERFLOW if the page would become too empty
 @retval DB_ZIP_OVERFLOW if there is not enough space left
-on the compressed page (IBUF_BITMAP_FREE was reset outside mtr) */
+on a ROW_FORMAT=COMPRESSED page */
 dberr_t
 btr_cur_optimistic_update(
 /*======================*/
@@ -4025,7 +3784,6 @@ btr_cur_optimistic_update(
 	ulint		max_size;
 	ulint		new_rec_size;
 	ulint		old_rec_size;
-	ulint		max_ins_size = 0;
 	dtuple_t*	new_entry;
 	roll_ptr_t	roll_ptr;
 	ulint		i;
@@ -4034,19 +3792,16 @@ btr_cur_optimistic_update(
 	page = buf_block_get_frame(block);
 	rec = btr_cur_get_rec(cursor);
 	index = cursor->index();
-	ut_ad(index->has_locking());
 	ut_ad(trx_id > 0 || (flags & BTR_KEEP_SYS_FLAG)
 	      || index->table->is_temporary());
 	ut_ad(!!page_rec_is_comp(rec) == dict_table_is_comp(index->table));
 	ut_ad(mtr->memo_contains_flagged(block, MTR_MEMO_PAGE_X_FIX));
 	/* This is intended only for leaf page updates */
 	ut_ad(page_is_leaf(page));
-	/* The insert buffer tree should never be updated in place. */
-	ut_ad(!dict_index_is_ibuf(index));
 	ut_ad(dict_index_is_online_ddl(index) == !!(flags & BTR_CREATE_FLAG)
 	      || dict_index_is_clust(index));
 	ut_ad(thr_get_trx(thr)->id == trx_id
-	      || (flags & ulint(~(BTR_KEEP_POS_FLAG | BTR_KEEP_IBUF_BITMAP)))
+	      || (flags & ulint(~BTR_KEEP_POS_FLAG))
 	      == (BTR_NO_UNDO_LOG_FLAG | BTR_NO_LOCKING_FLAG
 		  | BTR_CREATE_FLAG | BTR_KEEP_SYS_FLAG));
 	ut_ad(fil_page_index_page_check(page));
@@ -4075,7 +3830,6 @@ btr_cur_optimistic_update(
 
 	if (rec_offs_any_extern(*offsets)) {
 any_extern:
-		ut_ad(!index->is_ibuf());
 		/* Externally stored fields are treated in pessimistic
 		update */
 
@@ -4156,9 +3910,6 @@ any_extern:
 	if (UNIV_UNLIKELY(new_rec_size
 			  >= (page_get_free_space_of_empty(page_is_comp(page))
 			      / 2))) {
-		/* We may need to update the IBUF_BITMAP_FREE
-		bits after a reorganize that was done in
-		btr_cur_update_alloc_zip(). */
 		err = DB_OVERFLOW;
 		goto func_exit;
 	}
@@ -4166,10 +3917,6 @@ any_extern:
 	if (UNIV_UNLIKELY(page_get_data_size(page)
 			  - old_rec_size + new_rec_size
 			  < BTR_CUR_PAGE_COMPRESS_LIMIT(index))) {
-		/* We may need to update the IBUF_BITMAP_FREE
-		bits after a reorganize that was done in
-		btr_cur_update_alloc_zip(). */
-
 		/* The page would become too empty */
 		err = DB_UNDERFLOW;
 		goto func_exit;
@@ -4182,19 +3929,9 @@ any_extern:
 		: (old_rec_size
 		   + page_get_max_insert_size_after_reorganize(page, 1));
 
-	if (!page_zip) {
-		max_ins_size = page_get_max_insert_size_after_reorganize(
-				page, 1);
-	}
-
 	if (!(((max_size >= BTR_CUR_PAGE_REORGANIZE_LIMIT)
 	       && (max_size >= new_rec_size))
 	      || (page_get_n_recs(page) <= 1))) {
-
-		/* We may need to update the IBUF_BITMAP_FREE
-		bits after a reorganize that was done in
-		btr_cur_update_alloc_zip(). */
-
 		/* There was not enough space, or it did not pay to
 		reorganize: for simplicity, we decide what to do assuming a
 		reorganization is needed, though it might not be necessary */
@@ -4208,9 +3945,6 @@ any_extern:
 					update, cmpl_info,
 					thr, mtr, &roll_ptr);
 	if (err != DB_SUCCESS) {
-		/* We may need to update the IBUF_BITMAP_FREE
-		bits after a reorganize that was done in
-		btr_cur_update_alloc_zip(). */
 		goto func_exit;
 	}
 
@@ -4266,22 +4000,11 @@ any_extern:
 	ut_ad(err == DB_SUCCESS);
 	if (!page_cur_move_to_next(page_cursor)) {
 corrupted:
-		err = DB_CORRUPTION;
-	}
-
-func_exit:
-	if (!(flags & BTR_KEEP_IBUF_BITMAP)
-	    && !dict_index_is_clust(index)) {
-		/* Update the free bits in the insert buffer. */
-		if (page_zip) {
-			ut_ad(!index->table->is_temporary());
-			ibuf_update_free_bits_zip(block, mtr);
-		} else if (!index->table->is_temporary()) {
-			ibuf_update_free_bits_low(block, max_ins_size, mtr);
-		}
+		return DB_CORRUPTION;
 	}
 
 	if (err != DB_SUCCESS) {
+func_exit:
 		/* prefetch siblings of the leaf for the pessimistic
 		operation. */
 		btr_cur_prefetch_siblings(block, index);
@@ -4378,7 +4101,6 @@ btr_cur_pessimistic_update(
 	big_rec_t*	dummy_big_rec;
 	dict_index_t*	index;
 	buf_block_t*	block;
-	page_zip_des_t*	page_zip;
 	rec_t*		rec;
 	page_cur_t*	page_cursor;
 	dberr_t		err;
@@ -4391,20 +4113,19 @@ btr_cur_pessimistic_update(
 	*big_rec = NULL;
 
 	block = btr_cur_get_block(cursor);
-	page_zip = buf_block_get_page_zip(block);
 	index = cursor->index();
-	ut_ad(index->has_locking());
 
 	ut_ad(mtr->memo_contains_flagged(&index->lock, MTR_MEMO_X_LOCK |
 					 MTR_MEMO_SX_LOCK));
 	ut_ad(mtr->memo_contains_flagged(block, MTR_MEMO_PAGE_X_FIX));
+#if defined UNIV_ZIP_DEBUG || defined UNIV_DEBUG
+	page_zip_des_t*	page_zip = buf_block_get_page_zip(block);
+#endif
 #ifdef UNIV_ZIP_DEBUG
 	ut_a(!page_zip
 	     || page_zip_validate(page_zip, block->page.frame, index));
 #endif /* UNIV_ZIP_DEBUG */
 	ut_ad(!page_zip || !index->table->is_temporary());
-	/* The insert buffer tree should never be updated in place. */
-	ut_ad(!dict_index_is_ibuf(index));
 	ut_ad(trx_id > 0 || (flags & BTR_KEEP_SYS_FLAG)
 	      || index->table->is_temporary());
 	ut_ad(dict_index_is_online_ddl(index) == !!(flags & BTR_CREATE_FLAG)
@@ -4415,7 +4136,7 @@ btr_cur_pessimistic_update(
 		  | BTR_CREATE_FLAG | BTR_KEEP_SYS_FLAG));
 
 	err = optim_err = btr_cur_optimistic_update(
-		flags | BTR_KEEP_IBUF_BITMAP,
+		flags,
 		cursor, offsets, offsets_heap, update,
 		cmpl_info, thr, trx_id, mtr);
 
@@ -4426,18 +4147,6 @@ btr_cur_pessimistic_update(
 		break;
 	default:
 	err_exit:
-		/* We suppressed this with BTR_KEEP_IBUF_BITMAP.
-		For DB_ZIP_OVERFLOW, the IBUF_BITMAP_FREE bits were
-		already reset by btr_cur_update_alloc_zip() if the
-		page was recompressed. */
-		if (page_zip
-		    && optim_err != DB_ZIP_OVERFLOW
-		    && !dict_index_is_clust(index)
-		    && page_is_leaf(block->page.frame)) {
-			ut_ad(!index->table->is_temporary());
-			ibuf_update_free_bits_zip(block, mtr);
-		}
-
 		if (big_rec_vec != NULL) {
 			dtuple_big_rec_free(big_rec_vec);
 		}
@@ -4515,11 +4224,6 @@ btr_cur_pessimistic_update(
 					  index->first_user_field())))) {
 		big_rec_vec = dtuple_convert_big_rec(index, update, new_entry, &n_ext);
 		if (UNIV_UNLIKELY(big_rec_vec == NULL)) {
-
-			/* We cannot goto return_after_reservations,
-			because we may need to update the
-			IBUF_BITMAP_FREE bits, which was suppressed by
-			BTR_KEEP_IBUF_BITMAP. */
 #ifdef UNIV_ZIP_DEBUG
 			ut_a(!page_zip
 			     || page_zip_validate(page_zip, block->page.frame,
@@ -4564,11 +4268,6 @@ btr_cur_pessimistic_update(
 		btr_cur_write_sys(new_entry, index, trx_id, roll_ptr);
 	}
 
-	const ulint max_ins_size = page_zip
-		? 0
-		: page_get_max_insert_size_after_reorganize(block->page.frame,
-							    1);
-
 	if (UNIV_UNLIKELY(is_metadata)) {
 		ut_ad(new_entry->is_metadata());
 		ut_ad(index->is_instant());
@@ -4653,18 +4352,6 @@ btr_cur_pessimistic_update(
 				rec_offs_make_valid(page_cursor->rec, index,
 						    true, *offsets);
 			}
-		} else if (!dict_index_is_clust(index)
-			   && page_is_leaf(block->page.frame)) {
-			/* Update the free bits in the insert buffer.
-			This is the same block which was skipped by
-			BTR_KEEP_IBUF_BITMAP. */
-			if (page_zip) {
-				ut_ad(!index->table->is_temporary());
-				ibuf_update_free_bits_zip(block, mtr);
-			} else if (!index->table->is_temporary()) {
-				ibuf_update_free_bits_low(block, max_ins_size,
-							  mtr);
-			}
 		}
 
 		if (!srv_read_only_mode
@@ -4686,16 +4373,7 @@ btr_cur_pessimistic_update(
 		of a badly-compressing record, it is possible for
 		btr_cur_optimistic_update() to return DB_UNDERFLOW and
 		btr_cur_insert_if_possible() to return FALSE. */
-		ut_a(page_zip || optim_err != DB_UNDERFLOW);
-
-		/* Out of space: reset the free bits.
-		This is the same block which was skipped by
-		BTR_KEEP_IBUF_BITMAP. */
-		if (!dict_index_is_clust(index)
-		    && !index->table->is_temporary()
-		    && page_is_leaf(block->page.frame)) {
-			ibuf_reset_free_bits(block);
-		}
+		ut_ad(page_zip || optim_err != DB_UNDERFLOW);
 	}
 
 	if (big_rec_vec != NULL) {
@@ -4740,8 +4418,7 @@ btr_cur_pessimistic_update(
 	same temp-table in parallel.
 	max_trx_id is ignored for temp tables because it not required
 	for MVCC. */
-	if (dict_index_is_sec_or_ibuf(index)
-	    && !index->table->is_temporary()) {
+	if (!index->is_primary() && !index->table->is_temporary()) {
 		/* Update PAGE_MAX_TRX_ID in the index page header.
 		It was not updated by btr_cur_pessimistic_insert()
 		because of BTR_NO_LOCKING_FLAG. */
@@ -5052,9 +4729,6 @@ btr_cur_optimistic_delete(
 	}
 
 	{
-		page_t*		page	= buf_block_get_frame(block);
-		page_zip_des_t*	page_zip= buf_block_get_page_zip(block);
-
 		if (UNIV_UNLIKELY(rec_get_info_bits(rec, page_rec_is_comp(rec))
 				  & REC_INFO_MIN_REC_FLAG)) {
 			/* This should be rolling back instant ADD COLUMN.
@@ -5063,7 +4737,7 @@ btr_cur_optimistic_delete(
 			insert into SYS_COLUMNS is rolled back. */
 			ut_ad(cursor->index()->table->supports_instant());
 			ut_ad(cursor->index()->is_primary());
-			ut_ad(!page_zip);
+			ut_ad(!buf_block_get_page_zip(block));
 			page_cur_delete_rec(btr_cur_get_page_cur(cursor),
 					    offsets, mtr);
 			/* We must empty the PAGE_FREE list, because
@@ -5081,40 +4755,8 @@ btr_cur_optimistic_delete(
 			btr_search_update_hash_on_delete(cursor);
 		}
 
-		if (page_zip) {
-#ifdef UNIV_ZIP_DEBUG
-			ut_a(page_zip_validate(page_zip, page,
-					       cursor->index()));
-#endif /* UNIV_ZIP_DEBUG */
-			page_cur_delete_rec(btr_cur_get_page_cur(cursor),
-					    offsets, mtr);
-#ifdef UNIV_ZIP_DEBUG
-			ut_a(page_zip_validate(page_zip, page,
-					       cursor->index()));
-#endif /* UNIV_ZIP_DEBUG */
-
-			/* On compressed pages, the IBUF_BITMAP_FREE
-			space is not affected by deleting (purging)
-			records, because it is defined as the minimum
-			of space available *without* reorganize, and
-			space available in the modification log. */
-		} else {
-			const ulint	max_ins
-				= page_get_max_insert_size_after_reorganize(
-					page, 1);
-
-			page_cur_delete_rec(btr_cur_get_page_cur(cursor),
-					    offsets, mtr);
-
-			/* The change buffer does not handle inserts
-			into non-leaf pages, into clustered indexes,
-			or into the change buffer. */
-			if (!cursor->index()->is_clust()
-			    && !cursor->index()->table->is_temporary()
-			    && !dict_index_is_ibuf(cursor->index())) {
-				ibuf_update_free_bits_low(block, max_ins, mtr);
-			}
-		}
+		page_cur_delete_rec(btr_cur_get_page_cur(cursor),
+				    offsets, mtr);
 	}
 
 func_exit:
@@ -5310,9 +4952,9 @@ discard_page:
 			goto err_exit;
 		}
 
-		btr_cur_t cursor;
-		cursor.page_cur.index = index;
-		cursor.page_cur.block = block;
+		btr_cur_t cur;
+		cur.page_cur.index = index;
+		cur.page_cur.block = block;
 
 		if (!page_has_prev(page)) {
 			/* If we delete the leftmost node pointer on a
@@ -5328,16 +4970,17 @@ discard_page:
 			rec_offs*	offsets;
 			ulint		len;
 
-			rtr_page_get_father_block(NULL, heap, mtr, NULL,
-						  &cursor);
-			father_rec = btr_cur_get_rec(&cursor);
+			rtr_page_get_father_block(nullptr, heap, nullptr,
+						  &cur,
+						  cursor->rtr_info->thr, mtr);
+			father_rec = btr_cur_get_rec(&cur);
 			offsets = rec_get_offsets(father_rec, index, NULL,
 						  0, ULINT_UNDEFINED, &heap);
 
 			rtr_read_mbr(rec_get_nth_field(
 				father_rec, offsets, 0, &len), &father_mbr);
 
-			rtr_update_mbr_field(&cursor, offsets, NULL,
+			rtr_update_mbr_field(&cur, offsets, NULL,
 					     page, &father_mbr, next_rec, mtr);
 			ut_d(parent_latched = true);
 		} else {
@@ -5345,12 +4988,12 @@ discard_page:
 			on a page, we have to change the parent node pointer
 			so that it is equal to the new leftmost node pointer
 			on the page */
-			ret = btr_page_get_father(mtr, &cursor);
+			ret = btr_page_get_father(mtr, &cur);
 			if (!ret) {
 				*err = DB_CORRUPTION;
 				goto err_exit;
 			}
-			*err = btr_cur_node_ptr_delete(&cursor, mtr);
+			*err = btr_cur_node_ptr_delete(&cur, mtr);
 			if (*err != DB_SUCCESS) {
 got_err:
 				ret = FALSE;
@@ -5397,7 +5040,10 @@ got_err:
 #endif /* UNIV_ZIP_DEBUG */
 
 		ut_ad(!parent_latched
-		      || btr_check_node_ptr(index, block, mtr));
+		      || btr_check_node_ptr(index, block,
+					    cursor->rtr_info
+					    ? cursor->rtr_info->thr
+					    : nullptr, mtr));
 
 		if (!ret && btr_cur_compress_recommendation(cursor, mtr)) {
 			if (UNIV_LIKELY(allow_merge)) {
@@ -5544,7 +5190,7 @@ public:
     ulint parent_savepoint= m_savepoint;
 
     m_savepoint= mtr_set_savepoint(&mtr);
-    m_block= btr_block_get(*index(), m_page_id.page_no(), RW_S_LATCH, !level,
+    m_block= btr_block_get(*index(), m_page_id.page_no(), RW_S_LATCH,
                            &mtr, nullptr);
 
     if (parent_block && parent_block != right_parent)
@@ -5762,8 +5408,7 @@ static ha_rows btr_estimate_n_rows_in_range_on_level(
     savepoint= mtr_set_savepoint(&mtr);
 
     /* Fetch the page. */
-    block= btr_block_get(*index, page_id.page_no(), RW_S_LATCH, !level, &mtr,
-                         nullptr);
+    block= btr_block_get(*index, page_id.page_no(), RW_S_LATCH, &mtr, nullptr);
 
     if (prev_block)
       mtr_release_block_at_savepoint(&mtr, prev_savepoint, prev_block);
@@ -6378,7 +6023,7 @@ struct btr_blob_log_check_t {
 
 		if (UNIV_UNLIKELY(page_no != FIL_NULL)) {
 			m_pcur->btr_cur.page_cur.block = btr_block_get(
-				*index, page_no, RW_X_LATCH, false, m_mtr);
+				*index, page_no, RW_X_LATCH, m_mtr);
 			/* The page should not be evicted or corrupted while
 			we are holding a buffer-fix on it. */
 			m_pcur->btr_cur.page_cur.block->page.unfix();
diff --git a/storage/innobase/btr/btr0defragment.cc b/storage/innobase/btr/btr0defragment.cc
index 76b173359da..bd2f4e0cbfc 100644
--- a/storage/innobase/btr/btr0defragment.cc
+++ b/storage/innobase/btr/btr0defragment.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (C) 2012, 2014 Facebook, Inc. All Rights Reserved.
-Copyright (C) 2014, 2022, MariaDB Corporation.
+Copyright (C) 2014, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -33,7 +33,6 @@ Modified 30/07/2014 Jan Lindström jan.lindstrom@mariadb.com
 #include "dict0stats.h"
 #include "dict0stats_bg.h"
 #include "dict0defrag_bg.h"
-#include "ibuf0ibuf.h"
 #include "lock0lock.h"
 #include "srv0start.h"
 #include "mysqld.h"
@@ -330,20 +329,16 @@ btr_defragment_merge_pages(
 	// If max_ins_size >= move_size, we can move the records without
 	// reorganizing the page, otherwise we need to reorganize the page
 	// first to release more space.
-	if (move_size > max_ins_size) {
-		dberr_t err = btr_page_reorganize_block(page_zip_level,
-                                                        to_block, index, mtr);
-		if (err != DB_SUCCESS) {
-			if (!dict_index_is_clust(index)
-			    && page_is_leaf(to_page)) {
-				ibuf_reset_free_bits(to_block);
-			}
-			// If reorganization fails, that means page is
-			// not compressable. There's no point to try
-			// merging into this page. Continue to the
-			// next page.
-			return err == DB_FAIL ? from_block : nullptr;
-		}
+	if (move_size <= max_ins_size) {
+	} else if (dberr_t err = btr_page_reorganize_block(page_zip_level,
+							   to_block, index,
+							   mtr)) {
+		// If reorganization fails, that means page is
+		// not compressable. There's no point to try
+		// merging into this page. Continue to the
+		// next page.
+		return err == DB_FAIL ? from_block : nullptr;
+	} else {
 		ut_ad(page_validate(to_page, index));
 		max_ins_size = page_get_max_insert_size(to_page, n_recs);
 		if (max_ins_size < move_size) {
@@ -392,18 +387,6 @@ btr_defragment_merge_pages(
 	    && *max_data_size > new_data_size + move_size) {
 		*max_data_size = new_data_size + move_size;
 	}
-	// Set ibuf free bits if necessary.
-	if (!dict_index_is_clust(index)
-	    && page_is_leaf(to_page)) {
-		if (zip_size) {
-			ibuf_reset_free_bits(to_block);
-		} else {
-			ibuf_update_free_bits_if_full(
-				to_block,
-				srv_page_size,
-				ULINT_UNDEFINED);
-		}
-	}
 	btr_cur_t parent;
 	parent.page_cur.index = index;
 	parent.page_cur.block = from_block;
@@ -526,8 +509,7 @@ btr_defragment_n_pages(
 			break;
 		}
 
-		blocks[i] = btr_block_get(*index, page_no, RW_X_LATCH, true,
-					  mtr);
+		blocks[i] = btr_block_get(*index, page_no, RW_X_LATCH, mtr);
 		if (!blocks[i]) {
 			return nullptr;
 		}
@@ -542,7 +524,7 @@ btr_defragment_n_pages(
 			/* given page is the last page.
 			Lift the records to father. */
 			dberr_t err;
-			btr_lift_page_up(index, block, mtr, &err);
+			btr_lift_page_up(index, block, nullptr, mtr, &err);
 		}
 		return NULL;
 	}
diff --git a/storage/innobase/btr/btr0pcur.cc b/storage/innobase/btr/btr0pcur.cc
index 46b8d487850..640b1b4ea2a 100644
--- a/storage/innobase/btr/btr0pcur.cc
+++ b/storage/innobase/btr/btr0pcur.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2016, 2022, MariaDB Corporation.
+Copyright (c) 2016, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -157,20 +157,14 @@ before_first:
 		cursor->rel_pos = BTR_PCUR_ON;
 	}
 
-	if (index->is_ibuf()) {
-		ut_ad(!index->table->not_redundant());
-		cursor->old_n_fields = uint16_t(rec_get_n_fields_old(rec));
-	} else {
-		cursor->old_n_fields = static_cast<uint16>(
-			dict_index_get_n_unique_in_tree(index));
-		if (index->is_spatial() && !page_rec_is_leaf(rec)) {
-			ut_ad(dict_index_get_n_unique_in_tree_nonleaf(index)
-			      == DICT_INDEX_SPATIAL_NODEPTR_SIZE);
-			/* For R-tree, we have to compare
-			the child page numbers as well. */
-			cursor->old_n_fields
-				= DICT_INDEX_SPATIAL_NODEPTR_SIZE + 1;
-		}
+	cursor->old_n_fields = static_cast<uint16>(
+		dict_index_get_n_unique_in_tree(index));
+	if (index->is_spatial() && !page_rec_is_leaf(rec)) {
+		ut_ad(dict_index_get_n_unique_in_tree_nonleaf(index)
+		      == DICT_INDEX_SPATIAL_NODEPTR_SIZE);
+		/* For R-tree, we have to compare
+		the child page numbers as well. */
+		cursor->old_n_fields = DICT_INDEX_SPATIAL_NODEPTR_SIZE + 1;
 	}
 
 	cursor->old_n_core_fields = index->n_core_fields;
@@ -476,8 +470,7 @@ btr_pcur_move_to_next_page(
 
 	dberr_t err;
 	buf_block_t* next_block = btr_block_get(
-		*cursor->index(), next_page_no, mode,
-		page_is_leaf(page), mtr, &err);
+		*cursor->index(), next_page_no, mode, mtr, &err);
 
 	if (UNIV_UNLIKELY(!next_block)) {
 		return err;
diff --git a/storage/innobase/btr/btr0sea.cc b/storage/innobase/btr/btr0sea.cc
index c61cdd9f604..93bb4825a3d 100644
--- a/storage/innobase/btr/btr0sea.cc
+++ b/storage/innobase/btr/btr0sea.cc
@@ -2,7 +2,7 @@
 
 Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2008, Google Inc.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 Portions of this file contain modifications contributed and copyrighted by
 Google, Inc. Those modifications are gratefully acknowledged and are described
@@ -305,13 +305,6 @@ static void btr_search_info_update_hash(btr_search_t *info, btr_cur_t *cursor)
 	dict_index_t*	index = cursor->index();
 	int		cmp;
 
-	if (dict_index_is_ibuf(index)) {
-		/* So many deletes are performed on an insert buffer tree
-		that we do not consider a hash index useful on it: */
-
-		return;
-	}
-
 	uint16_t n_unique = dict_index_get_n_unique_in_tree(index);
 
 	if (info->n_hash_potential == 0) {
@@ -712,7 +705,6 @@ btr_search_update_hash_ref(
 
 	ut_ad(block->page.id().space() == index->table->space_id);
 	ut_ad(index == cursor->index());
-	ut_ad(!dict_index_is_ibuf(index));
 	auto part = btr_search_sys.get_part(*index);
 	part->latch.wr_lock(SRW_LOCK_CALL);
 	ut_ad(!block->index || block->index == index);
@@ -1062,7 +1054,6 @@ btr_search_guess_on_hash(
 		return false;
 	}
 
-	ut_ad(!index->is_ibuf());
 	ut_ad(latch_mode == BTR_SEARCH_LEAF || latch_mode == BTR_MODIFY_LEAF);
 	compile_time_assert(ulint{BTR_SEARCH_LEAF} == ulint{RW_S_LATCH});
 	compile_time_assert(ulint{BTR_MODIFY_LEAF} == ulint{RW_X_LATCH});
@@ -1269,7 +1260,6 @@ retry:
 
 	ut_ad(block->page.id().space() == index->table->space_id);
 	ut_a(index_id == index->id);
-	ut_ad(!dict_index_is_ibuf(index));
 
 	n_fields = block->curr_n_fields;
 	n_bytes = block->curr_n_bytes;
@@ -1472,7 +1462,6 @@ btr_search_build_page_hash_index(
 	ut_ad(ahi_latch == &btr_search_sys.get_part(*index)->latch);
 	ut_ad(index);
 	ut_ad(block->page.id().space() == index->table->space_id);
-	ut_ad(!dict_index_is_ibuf(index));
 	ut_ad(page_is_leaf(block->page.frame));
 
 	ut_ad(block->page.lock.have_x() || block->page.lock.have_s());
@@ -1798,7 +1787,6 @@ void btr_search_update_hash_on_delete(btr_cur_t *cursor)
 	ut_ad(block->page.id().space() == index->table->space_id);
 	ut_a(index == cursor->index());
 	ut_a(block->curr_n_fields > 0 || block->curr_n_bytes > 0);
-	ut_ad(!dict_index_is_ibuf(index));
 
 	rec = btr_cur_get_rec(cursor);
 
@@ -1871,7 +1859,6 @@ void btr_search_update_hash_node_on_insert(btr_cur_t *cursor,
 	}
 
 	ut_a(cursor->index() == index);
-	ut_ad(!dict_index_is_ibuf(index));
 	ahi_latch->wr_lock(SRW_LOCK_CALL);
 
 	if (!block->index || !btr_search_enabled) {
@@ -1964,7 +1951,6 @@ drop:
 	}
 
 	ut_a(index == cursor->index());
-	ut_ad(!dict_index_is_ibuf(index));
 
 	n_fields = block->curr_n_fields;
 	n_bytes = block->curr_n_bytes;
@@ -2213,7 +2199,6 @@ btr_search_hash_table_validate(ulint hash_table_id)
 			invokes btr_search_drop_page_hash_index(). */
 			ut_a(block->page.state() == buf_page_t::REMOVE_HASH);
 state_ok:
-			ut_ad(!dict_index_is_ibuf(block->index));
 			ut_ad(block->page.id().space()
 			      == block->index->table->space_id);
 
diff --git a/storage/innobase/buf/buf0buf.cc b/storage/innobase/buf/buf0buf.cc
index ce6a525d080..e48538545f0 100644
--- a/storage/innobase/buf/buf0buf.cc
+++ b/storage/innobase/buf/buf0buf.cc
@@ -2,7 +2,7 @@
 
 Copyright (c) 1995, 2018, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2008, Google Inc.
-Copyright (c) 2013, 2022, MariaDB Corporation.
+Copyright (c) 2013, 2023, MariaDB Corporation.
 
 Portions of this file contain modifications contributed and copyrighted by
 Google, Inc. Those modifications are gratefully acknowledged and are described
@@ -50,7 +50,6 @@ Created 11/5/1995 Heikki Tuuri
 #include "buf0dblwr.h"
 #include "lock0lock.h"
 #include "btr0sea.h"
-#include "ibuf0ibuf.h"
 #include "trx0undo.h"
 #include "trx0purge.h"
 #include "log0log.h"
@@ -1820,9 +1819,6 @@ calc_buf_pool_size:
 			" and dictionary.";
 	}
 
-	/* normalize ibuf.max_size */
-	ibuf_max_size_update(srv_change_buffer_max_size);
-
 	if (srv_buf_pool_old_size != srv_buf_pool_size) {
 
 	        buf_resize_status("Completed resizing buffer pool from %zu to %zu bytes."
@@ -1896,7 +1892,6 @@ static void buf_relocate(buf_page_t *bpage, buf_page_t *dpage)
   mysql_mutex_assert_owner(&buf_pool.mutex);
   ut_ad(buf_pool.page_hash.lock_get(chain).is_write_locked());
   ut_ad(bpage == buf_pool.page_hash.get(id, chain));
-  ut_ad(!buf_pool.watch_is_sentinel(*bpage));
   ut_d(const auto state= bpage->state());
   ut_ad(state >= buf_page_t::FREED);
   ut_ad(state <= buf_page_t::READ_FIX);
@@ -1940,135 +1935,6 @@ static void buf_relocate(buf_page_t *bpage, buf_page_t *dpage)
   buf_pool.page_hash.replace(chain, bpage, dpage);
 }
 
-/** Register a watch for a page identifier. The caller must hold an
-exclusive page hash latch. The *hash_lock may be released,
-relocated, and reacquired.
-@param id         page identifier
-@param chain      hash table chain with exclusively held page_hash
-@return a buffer pool block corresponding to id
-@retval nullptr   if the block was not present, and a watch was installed */
-inline buf_page_t *buf_pool_t::watch_set(const page_id_t id,
-                                         buf_pool_t::hash_chain &chain)
-{
-  ut_ad(&chain == &page_hash.cell_get(id.fold()));
-  ut_ad(page_hash.lock_get(chain).is_write_locked());
-
-retry:
-  if (buf_page_t *bpage= page_hash.get(id, chain))
-  {
-    if (!watch_is_sentinel(*bpage))
-      /* The page was loaded meanwhile. */
-      return bpage;
-    /* Add to an existing watch. */
-    bpage->fix();
-    return nullptr;
-  }
-
-  page_hash.lock_get(chain).unlock();
-  /* Allocate a watch[] and then try to insert it into the page_hash. */
-  mysql_mutex_lock(&mutex);
-
-  /* The maximum number of purge tasks should never exceed
-  the UT_ARR_SIZE(watch) - 1, and there is no way for a purge task to hold a
-  watch when setting another watch. */
-  for (buf_page_t *w= &watch[UT_ARR_SIZE(watch)]; w-- >= watch; )
-  {
-    ut_ad(w->access_time == 0);
-    ut_ad(!w->oldest_modification());
-    ut_ad(!w->zip.data);
-    ut_ad(!w->in_zip_hash);
-    static_assert(buf_page_t::NOT_USED == 0, "efficiency");
-    if (ut_d(auto s=) w->state())
-    {
-      /* This watch may be in use for some other page. */
-      ut_ad(s >= buf_page_t::UNFIXED);
-      continue;
-    }
-    /* w is pointing to watch[], which is protected by mutex.
-    Normally, buf_page_t::id for objects that are reachable by
-    page_hash.get(id, chain) are protected by hash_lock. */
-    w->set_state(buf_page_t::UNFIXED + 1);
-    w->id_= id;
-
-    buf_page_t *bpage= page_hash.get(id, chain);
-    if (UNIV_LIKELY_NULL(bpage))
-    {
-      w->set_state(buf_page_t::NOT_USED);
-      page_hash.lock_get(chain).lock();
-      mysql_mutex_unlock(&mutex);
-      goto retry;
-    }
-
-    page_hash.lock_get(chain).lock();
-    ut_ad(w->state() == buf_page_t::UNFIXED + 1);
-    buf_pool.page_hash.append(chain, w);
-    mysql_mutex_unlock(&mutex);
-    return nullptr;
-  }
-
-  ut_error;
-  mysql_mutex_unlock(&mutex);
-  return nullptr;
-}
-
-/** Stop watching whether a page has been read in.
-watch_set(id) must have returned nullptr before.
-@param id         page identifier
-@param chain      unlocked hash table chain */
-TRANSACTIONAL_TARGET
-void buf_pool_t::watch_unset(const page_id_t id, buf_pool_t::hash_chain &chain)
-{
-  mysql_mutex_assert_not_owner(&mutex);
-  buf_page_t *w;
-  {
-    transactional_lock_guard<page_hash_latch> g{page_hash.lock_get(chain)};
-    /* The page must exist because watch_set() did fix(). */
-    w= page_hash.get(id, chain);
-    ut_ad(w->in_page_hash);
-    if (!watch_is_sentinel(*w))
-    {
-    no_watch:
-      w->unfix();
-      w= nullptr;
-    }
-    else
-    {
-      const auto state= w->state();
-      ut_ad(~buf_page_t::LRU_MASK & state);
-      ut_ad(state >= buf_page_t::UNFIXED + 1);
-      if (state != buf_page_t::UNFIXED + 1)
-        goto no_watch;
-    }
-  }
-
-  if (!w)
-    return;
-
-  const auto old= w;
-  /* The following is based on buf_pool_t::watch_remove(). */
-  mysql_mutex_lock(&mutex);
-  w= page_hash.get(id, chain);
-
-  {
-    transactional_lock_guard<page_hash_latch> g
-      {buf_pool.page_hash.lock_get(chain)};
-    auto f= w->unfix();
-    ut_ad(f < buf_page_t::READ_FIX || w != old);
-
-    if (f == buf_page_t::UNFIXED && w == old)
-    {
-      page_hash.remove(chain, w);
-      // Now that w is detached from page_hash, release it to watch[].
-      ut_ad(w->id_ == id);
-      ut_ad(!w->frame);
-      ut_ad(!w->zip.data);
-      w->set_state(buf_page_t::NOT_USED);
-    }
-  }
-
-  mysql_mutex_unlock(&mutex);
-}
-
 /** Mark the page status as FREED for the given tablespace and page number.
 @param[in,out]	space	tablespace
 @param[in]	page	page number
@@ -2150,7 +2016,7 @@ lookup:
       if (hash_lock.is_locked())
         xabort();
       bpage= buf_pool.page_hash.get(page_id, chain);
-      if (!bpage || buf_pool.watch_is_sentinel(*bpage))
+      if (!bpage)
       {
         xend();
         goto must_read_page;
@@ -2175,7 +2041,7 @@ lookup:
     {
       hash_lock.lock_shared();
       bpage= buf_pool.page_hash.get(page_id, chain);
-      if (!bpage || buf_pool.watch_is_sentinel(*bpage))
+      if (!bpage)
       {
         hash_lock.unlock_shared();
         goto must_read_page;
@@ -2348,13 +2214,9 @@ err_exit:
 @param[in]	rw_latch		RW_S_LATCH, RW_X_LATCH, RW_NO_LATCH
 @param[in]	guess			guessed block or NULL
 @param[in]	mode			BUF_GET, BUF_GET_IF_IN_POOL,
-BUF_PEEK_IF_IN_POOL, or BUF_GET_IF_IN_POOL_OR_WATCH
+or BUF_PEEK_IF_IN_POOL
 @param[in]	mtr			mini-transaction
 @param[out]	err			DB_SUCCESS or error code
-@param[in]	allow_ibuf_merge	Allow change buffer merge to happen
-while reading the page from file
-then it makes sure that it does merging of change buffer changes while
-reading the page from file.
 @return pointer to the block or NULL */
 TRANSACTIONAL_TARGET
 buf_block_t*
@@ -2365,10 +2227,8 @@ buf_page_get_low(
 	buf_block_t*		guess,
 	ulint			mode,
 	mtr_t*			mtr,
-	dberr_t*		err,
-	bool			allow_ibuf_merge)
+	dberr_t*		err)
 {
-	unsigned	access_time;
 	ulint		retries = 0;
 
 	ut_ad(!mtr || mtr->is_active());
@@ -2377,11 +2237,6 @@ buf_page_get_low(
 	      || (rw_latch == RW_X_LATCH)
 	      || (rw_latch == RW_SX_LATCH)
 	      || (rw_latch == RW_NO_LATCH));
-	ut_ad(!allow_ibuf_merge
-	      || mode == BUF_GET
-	      || mode == BUF_GET_POSSIBLY_FREED
-	      || mode == BUF_GET_IF_IN_POOL
-	      || mode == BUF_GET_IF_IN_POOL_OR_WATCH);
 
 	if (err) {
 		*err = DB_SUCCESS;
@@ -2399,7 +2254,6 @@ buf_page_get_low(
 	case BUF_GET_POSSIBLY_FREED:
 		break;
 	case BUF_GET:
-	case BUF_GET_IF_IN_POOL_OR_WATCH:
 		ut_ad(!mtr->is_freeing_tree());
 		fil_space_t* s = fil_space_get(page_id.space());
 		ut_ad(s);
@@ -2407,9 +2261,6 @@ buf_page_get_low(
 	}
 #endif /* UNIV_DEBUG */
 
-	ut_ad(!mtr || !ibuf_inside(mtr)
-	      || ibuf_page_low(page_id, zip_size, FALSE, NULL));
-
 	++buf_pool.stat.n_page_gets;
 
 	auto& chain= buf_pool.page_hash.cell_get(page_id.fold());
@@ -2442,8 +2293,7 @@ loop:
 	hash_lock.lock_shared();
 	block = reinterpret_cast<buf_block_t*>(
 		buf_pool.page_hash.get(page_id, chain));
-	if (UNIV_LIKELY(block
-			&& !buf_pool.watch_is_sentinel(block->page))) {
+	if (UNIV_LIKELY(block != nullptr)) {
 		state = block->page.fix();
 		hash_lock.unlock_shared();
 		goto got_block;
@@ -2455,20 +2305,6 @@ loop:
 	case BUF_GET_IF_IN_POOL:
 	case BUF_PEEK_IF_IN_POOL:
 		return nullptr;
-	case BUF_GET_IF_IN_POOL_OR_WATCH:
-		/* We cannot easily use a memory transaction here. */
-		hash_lock.lock();
-		block = reinterpret_cast<buf_block_t*>
-			(buf_pool.watch_set(page_id, chain));
-		/* buffer-fixing will prevent eviction */
-		state = block ? block->page.fix() : 0;
-		hash_lock.unlock();
-
-		if (block) {
-			goto got_block;
-		}
-
-		return nullptr;
 	}
 
 	/* The call path is buf_read_page() ->
@@ -2495,7 +2331,7 @@ loop:
 			return nullptr;
 		}
 	} else {
-		buf_read_ahead_random(page_id, zip_size, ibuf_inside(mtr));
+		buf_read_ahead_random(page_id, zip_size);
 	}
 
 	ut_d(if (!(++buf_dbg_counter % 5771)) buf_pool.validate());
@@ -2603,7 +2439,6 @@ wait_for_unfix:
 
 		switch (state) {
 		case buf_page_t::UNFIXED + 1:
-		case buf_page_t::IBUF_EXIST + 1:
 		case buf_page_t::REINIT + 1:
 			break;
 		default:
@@ -2657,13 +2492,6 @@ wait_for_unfix:
 
 		buf_pool.n_pend_unzip++;
 
-		access_time = block->page.is_accessed();
-
-		if (!access_time && !recv_no_ibuf_operations
-		    && ibuf_page_exists(block->page.id(), block->zip_size())) {
-			state = buf_page_t::IBUF_EXIST + 1;
-		}
-
 		/* Decompress the page while not holding
 		buf_pool.mutex. */
 		auto ok = buf_zip_decompress(block, false);
@@ -2683,55 +2511,6 @@ wait_for_unfix:
 		}
 	}
 
-#if defined UNIV_DEBUG || defined UNIV_IBUF_DEBUG
-re_evict:
-	if (mode != BUF_GET_IF_IN_POOL
-	    && mode != BUF_GET_IF_IN_POOL_OR_WATCH) {
-	} else if (!ibuf_debug || recv_recovery_is_on()) {
-	} else if (fil_space_t* space = fil_space_t::get(page_id.space())) {
-		/* Try to evict the block from the buffer pool, to use the
-		insert buffer (change buffer) as much as possible. */
-
-		mysql_mutex_lock(&buf_pool.mutex);
-
-		block->unfix();
-
-		/* Blocks cannot be relocated or enter or exit the
-		buf_pool while we are holding the buf_pool.mutex. */
-		const bool evicted = buf_LRU_free_page(&block->page, true);
-		space->release();
-
-		if (evicted) {
-			page_hash_latch& hash_lock
-				= buf_pool.page_hash.lock_get(chain);
-			hash_lock.lock();
-			mysql_mutex_unlock(&buf_pool.mutex);
-			/* We may set the watch, as it would have
-			been set if the page were not in the
-			buffer pool in the first place. */
-			block= reinterpret_cast<buf_block_t*>(
-				mode == BUF_GET_IF_IN_POOL_OR_WATCH
-				? buf_pool.watch_set(page_id, chain)
-				: buf_pool.page_hash.get(page_id, chain));
-			hash_lock.unlock();
-			return(NULL);
-		}
-
-		block->fix();
-		mysql_mutex_unlock(&buf_pool.mutex);
-		buf_flush_sync();
-
-		state = block->page.state();
-
-		if (state == buf_page_t::UNFIXED + 1
-		    && !block->page.oldest_modification()) {
-			goto re_evict;
-		}
-
-		/* Failed to evict the page; change it directly */
-	}
-#endif /* UNIV_DEBUG || UNIV_IBUF_DEBUG */
-
 	ut_ad(state > buf_page_t::FREED);
 	if (UNIV_UNLIKELY(state < buf_page_t::UNFIXED)) {
 		goto ignore_block;
@@ -2744,118 +2523,69 @@ re_evict:
 #endif /* UNIV_DEBUG */
 	ut_ad(block->page.frame);
 
-	if (state >= buf_page_t::UNFIXED
-	    && allow_ibuf_merge
-	    && fil_page_get_type(block->page.frame) == FIL_PAGE_INDEX
-	    && page_is_leaf(block->page.frame)) {
-		block->page.lock.x_lock();
-		ut_ad(block->page.id() == page_id
-		      || (state >= buf_page_t::READ_FIX
-			  && state < buf_page_t::WRITE_FIX));
-
-#ifdef BTR_CUR_HASH_ADAPT
-		btr_search_drop_page_hash_index(block, true);
-#endif /* BTR_CUR_HASH_ADAPT */
-
-		dberr_t e;
+	mtr_memo_type_t fix_type;
 
+	switch (rw_latch) {
+	case RW_NO_LATCH:
+		mtr->memo_push(block, MTR_MEMO_BUF_FIX);
+		return block;
+	case RW_S_LATCH:
+		fix_type = MTR_MEMO_PAGE_S_FIX;
+		block->page.lock.s_lock();
+		ut_ad(!block->page.is_read_fixed());
 		if (UNIV_UNLIKELY(block->page.id() != page_id)) {
+			block->page.lock.s_unlock();
+			block->page.lock.x_lock();
 page_id_mismatch:
-			state = block->page.state();
-			e = DB_CORRUPTION;
-ibuf_merge_corrupted:
-			if (err) {
-				*err = e;
-			}
-
 			if (block->page.id().is_corrupted()) {
-				buf_pool.corrupted_evict(&block->page, state);
+				buf_pool.corrupted_evict(&block->page,
+							 block->page.state());
 			}
-			return nullptr;
-		}
-
-		state = block->page.state();
-		ut_ad(state < buf_page_t::READ_FIX);
-
-		if (state >= buf_page_t::IBUF_EXIST
-		    && state < buf_page_t::REINIT) {
-			block->page.clear_ibuf_exist();
-			e = ibuf_merge_or_delete_for_page(block, page_id,
-							  block->zip_size());
-			if (UNIV_UNLIKELY(e != DB_SUCCESS)) {
-				goto ibuf_merge_corrupted;
+			if (err) {
+				*err = DB_CORRUPTION;
 			}
+			return nullptr;
 		}
-
-		if (rw_latch == RW_X_LATCH) {
-			mtr->memo_push(block, MTR_MEMO_PAGE_X_FIX);
-			goto got_latch;
-		} else {
-			block->page.lock.x_unlock();
-			goto get_latch;
+		break;
+	case RW_SX_LATCH:
+		fix_type = MTR_MEMO_PAGE_SX_FIX;
+		block->page.lock.u_lock();
+		ut_ad(!block->page.is_io_fixed());
+		if (UNIV_UNLIKELY(block->page.id() != page_id)) {
+			block->page.lock.u_x_upgrade();
+			goto page_id_mismatch;
 		}
-	} else {
-get_latch:
-		switch (rw_latch) {
-			mtr_memo_type_t fix_type;
-		case RW_NO_LATCH:
-			mtr->memo_push(block, MTR_MEMO_BUF_FIX);
+		break;
+	default:
+		ut_ad(rw_latch == RW_X_LATCH);
+		fix_type = MTR_MEMO_PAGE_X_FIX;
+		if (block->page.lock.x_lock_upgraded()) {
+			ut_ad(block->page.id() == page_id);
+			block->unfix();
+			mtr->page_lock_upgrade(*block);
 			return block;
-		case RW_S_LATCH:
-			fix_type = MTR_MEMO_PAGE_S_FIX;
-			block->page.lock.s_lock();
-			ut_ad(!block->page.is_read_fixed());
-			if (UNIV_UNLIKELY(block->page.id() != page_id)) {
-				block->page.lock.s_unlock();
-				block->page.lock.x_lock();
-				goto page_id_mismatch;
-			}
-get_latch_valid:
-			mtr->memo_push(block, fix_type);
+		}
+		if (UNIV_UNLIKELY(block->page.id() != page_id)) {
+			goto page_id_mismatch;
+		}
+	}
+
+	mtr->memo_push(block, fix_type);
 #ifdef BTR_CUR_HASH_ADAPT
-			btr_search_drop_page_hash_index(block, true);
+	btr_search_drop_page_hash_index(block, true);
 #endif /* BTR_CUR_HASH_ADAPT */
-			break;
-		case RW_SX_LATCH:
-			fix_type = MTR_MEMO_PAGE_SX_FIX;
-			block->page.lock.u_lock();
-			ut_ad(!block->page.is_io_fixed());
-			if (UNIV_UNLIKELY(block->page.id() != page_id)) {
-				block->page.lock.u_x_upgrade();
-				goto page_id_mismatch;
-			}
-			goto get_latch_valid;
-		default:
-			ut_ad(rw_latch == RW_X_LATCH);
-			fix_type = MTR_MEMO_PAGE_X_FIX;
-			if (block->page.lock.x_lock_upgraded()) {
-				ut_ad(block->page.id() == page_id);
-				block->unfix();
-				mtr->page_lock_upgrade(*block);
-				return block;
-			}
-			if (UNIV_UNLIKELY(block->page.id() != page_id)) {
-				goto page_id_mismatch;
-			}
-			goto get_latch_valid;
-		}
 
-got_latch:
-		ut_ad(page_id_t(page_get_space_id(block->page.frame),
-				page_get_page_no(block->page.frame))
-		      == page_id);
+	ut_ad(page_id_t(page_get_space_id(block->page.frame),
+			page_get_page_no(block->page.frame)) == page_id);
 
-		if (mode == BUF_GET_POSSIBLY_FREED
-		    || mode == BUF_PEEK_IF_IN_POOL) {
-			return block;
-		}
+	if (mode == BUF_GET_POSSIBLY_FREED || mode == BUF_PEEK_IF_IN_POOL) {
+		return block;
+	}
 
-		const bool not_first_access{block->page.set_accessed()};
-		buf_page_make_young_if_needed(&block->page);
-		if (!not_first_access) {
-			buf_read_ahead_linear(page_id, block->zip_size(),
-					      ibuf_inside(mtr));
-		}
+	const bool not_first_access{block->page.set_accessed()};
+	buf_page_make_young_if_needed(&block->page);
+	if (!not_first_access) {
+		buf_read_ahead_linear(page_id, block->zip_size());
 	}
 
 	return block;
@@ -2867,11 +2597,9 @@ got_latch:
 @param[in]	rw_latch		RW_S_LATCH, RW_X_LATCH, RW_NO_LATCH
 @param[in]	guess			guessed block or NULL
 @param[in]	mode			BUF_GET, BUF_GET_IF_IN_POOL,
-BUF_PEEK_IF_IN_POOL, or BUF_GET_IF_IN_POOL_OR_WATCH
+or BUF_PEEK_IF_IN_POOL
 @param[in,out]	mtr			mini-transaction, or NULL
 @param[out]	err			DB_SUCCESS or error code
-@param[in]	allow_ibuf_merge	Allow change buffer merge while
-reading the pages from file.
 @return pointer to the block or NULL */
 buf_block_t*
 buf_page_get_gen(
@@ -2881,8 +2609,7 @@ buf_page_get_gen(
 	buf_block_t*		guess,
 	ulint			mode,
 	mtr_t*			mtr,
-	dberr_t*		err,
-	bool			allow_ibuf_merge)
+	dberr_t*		err)
 {
   if (buf_block_t *block= recv_sys.recover(page_id))
   {
@@ -2899,57 +2626,20 @@ buf_page_get_gen(
     /* The block may be write-fixed at this point because we are not
     holding a lock, but it must not be read-fixed. */
     ut_ad(s < buf_page_t::READ_FIX || s >= buf_page_t::WRITE_FIX);
-    if (err)
-      *err= DB_SUCCESS;
-    const bool must_merge= allow_ibuf_merge &&
-      ibuf_page_exists(page_id, block->zip_size());
     if (s < buf_page_t::UNFIXED)
     {
-    got_freed_page:
       ut_ad(mode == BUF_GET_POSSIBLY_FREED || mode == BUF_PEEK_IF_IN_POOL);
       block->page.unfix();
       goto corrupted;
     }
-    else if (must_merge &&
-             fil_page_get_type(block->page.frame) == FIL_PAGE_INDEX &&
-             page_is_leaf(block->page.frame))
-    {
-      block->page.lock.x_lock();
-      s= block->page.state();
-      ut_ad(s > buf_page_t::FREED);
-      ut_ad(s < buf_page_t::READ_FIX);
-      if (s < buf_page_t::UNFIXED)
-      {
-        block->page.lock.x_unlock();
-        goto got_freed_page;
-      }
-      else
-      {
-        if (block->page.is_ibuf_exist())
-          block->page.clear_ibuf_exist();
-        if (dberr_t e=
-            ibuf_merge_or_delete_for_page(block, page_id, block->zip_size()))
-        {
-          if (err)
-            *err= e;
-          buf_pool.corrupted_evict(&block->page, s);
-          return nullptr;
-        }
-      }
-
-      if (rw_latch == RW_X_LATCH)
-      {
-        mtr->memo_push(block, MTR_MEMO_PAGE_X_FIX);
-        return block;
-      }
-      block->page.lock.x_unlock();
-    }
+    if (err)
+      *err= DB_SUCCESS;
     mtr->page_lock(block, rw_latch);
     return block;
   }
 
   return buf_page_get_low(page_id, zip_size, rw_latch,
-                          guess, mode, mtr, err, allow_ibuf_merge);
+                          guess, mode, mtr, err);
 }
 
 /********************************************************************//**
@@ -3014,7 +2704,6 @@ bool buf_page_optimistic_get(ulint rw_latch, buf_block_t *block,
   {
     ut_ad(rw_latch == RW_S_LATCH || !block->page.is_io_fixed());
     ut_ad(id == block->page.id());
-    ut_ad(!ibuf_inside(mtr) || ibuf_page(id, block->zip_size(), nullptr));
 
     if (modify_clock != block->modify_clock || block->page.is_freed())
     {
@@ -3110,12 +2799,11 @@ retry:
 
   buf_page_t *bpage= buf_pool.page_hash.get(page_id, chain);
 
-  if (bpage && !buf_pool.watch_is_sentinel(*bpage))
+  if (bpage)
   {
 #ifdef BTR_CUR_HASH_ADAPT
     const dict_index_t *drop_hash_entry= nullptr;
 #endif
-    bool ibuf_exist= false;
 
     if (!mtr->have_x_latch(reinterpret_cast<const buf_block_t&>(*bpage)))
     {
@@ -3141,10 +2829,7 @@ retry:
       if (state < buf_page_t::UNFIXED)
         bpage->set_reinit(buf_page_t::FREED);
       else
-      {
         bpage->set_reinit(state & buf_page_t::LRU_MASK);
-        ibuf_exist= (state & buf_page_t::LRU_MASK) == buf_page_t::IBUF_EXIST;
-      }
 
       if (UNIV_LIKELY(bpage->frame != nullptr))
       {
@@ -3170,10 +2855,7 @@ retry:
         if (state < buf_page_t::UNFIXED)
           bpage->set_reinit(buf_page_t::FREED);
         else
-        {
           bpage->set_reinit(state & buf_page_t::LRU_MASK);
-          ibuf_exist= (state & buf_page_t::LRU_MASK) == buf_page_t::IBUF_EXIST;
-        }
 
         mysql_mutex_lock(&buf_pool.flush_list_mutex);
         buf_relocate(bpage, &free_block->page);
@@ -3213,9 +2895,6 @@ retry:
                                       false);
 #endif /* BTR_CUR_HASH_ADAPT */
 
-    if (ibuf_exist && !recv_recovery_is_on())
-      ibuf_merge_or_delete_for_page(nullptr, page_id, zip_size);
-
     return reinterpret_cast<buf_block_t*>(bpage);
   }
 
@@ -3256,13 +2935,6 @@ retry:
   bpage->set_accessed();
   buf_pool.stat.n_pages_created++;
 
-  /* Delete possible entries for the page from the insert buffer:
-  such can exist if the page belonged to an index which was dropped */
-  if (page_id < page_id_t{SRV_SPACE_ID_UPPER_BOUND, 0} &&
-      !srv_is_undo_tablespace(page_id.space()) &&
-      !recv_recovery_is_on())
-    ibuf_merge_or_delete_for_page(nullptr, page_id, zip_size);
-
   static_assert(FIL_PAGE_PREV + 4 == FIL_PAGE_NEXT, "adjacent");
   memset_aligned<8>(bpage->frame + FIL_PAGE_PREV, 0xff, 8);
   mach_write_to_2(bpage->frame + FIL_PAGE_TYPE, FIL_PAGE_TYPE_ALLOCATED);
@@ -3326,32 +2998,15 @@ ATTRIBUTE_COLD void buf_page_monitor(const buf_page_t &bpage, bool read)
 	const byte* frame = bpage.zip.data ? bpage.zip.data : bpage.frame;
 
 	switch (fil_page_get_type(frame)) {
-		ulint	level;
 	case FIL_PAGE_TYPE_INSTANT:
 	case FIL_PAGE_INDEX:
 	case FIL_PAGE_RTREE:
-		level = btr_page_get_level(frame);
-
-		/* Check if it is an index page for insert buffer */
-		if (fil_page_get_type(frame) == FIL_PAGE_INDEX
-		    && btr_page_get_index_id(frame)
-		    == (index_id_t)(DICT_IBUF_ID_MIN + IBUF_SPACE_ID)) {
-			if (level == 0) {
-				counter = MONITOR_RW_COUNTER(
-					read, MONITOR_INDEX_IBUF_LEAF_PAGE);
-			} else {
-				counter = MONITOR_RW_COUNTER(
-					read,
-					MONITOR_INDEX_IBUF_NON_LEAF_PAGE);
-			}
+		if (page_is_leaf(frame)) {
+			counter = MONITOR_RW_COUNTER(
+				read, MONITOR_INDEX_LEAF_PAGE);
 		} else {
-			if (level == 0) {
-				counter = MONITOR_RW_COUNTER(
-					read, MONITOR_INDEX_LEAF_PAGE);
-			} else {
-				counter = MONITOR_RW_COUNTER(
-					read, MONITOR_INDEX_NON_LEAF_PAGE);
-			}
+			counter = MONITOR_RW_COUNTER(
+				read, MONITOR_INDEX_NON_LEAF_PAGE);
 		}
 		break;
 
@@ -3363,14 +3018,6 @@ ATTRIBUTE_COLD void buf_page_monitor(const buf_page_t &bpage, bool read)
 		counter = MONITOR_RW_COUNTER(read, MONITOR_INODE_PAGE);
 		break;
 
-	case FIL_PAGE_IBUF_FREE_LIST:
-		counter = MONITOR_RW_COUNTER(read, MONITOR_IBUF_FREELIST_PAGE);
-		break;
-
-	case FIL_PAGE_IBUF_BITMAP:
-		counter = MONITOR_RW_COUNTER(read, MONITOR_IBUF_BITMAP_PAGE);
-		break;
-
 	case FIL_PAGE_TYPE_SYS:
 		counter = MONITOR_RW_COUNTER(read, MONITOR_SYSTEM_PAGE);
 		break;
@@ -3603,25 +3250,16 @@ release_page:
   if (recovery && !recv_recover_page(node.space, this))
     return DB_PAGE_CORRUPTED;
 
-  const bool ibuf_may_exist= frame && !recv_no_ibuf_operations &&
-    (!expected_id.space() || !is_predefined_tablespace(expected_id.space())) &&
-    fil_page_get_type(read_frame) == FIL_PAGE_INDEX &&
-    page_is_leaf(read_frame);
-
   if (UNIV_UNLIKELY(MONITOR_IS_ON(MONITOR_MODULE_BUF_PAGE)))
     buf_page_monitor(*this, true);
   DBUG_PRINT("ib_buf", ("read page %u:%u", id().space(), id().page_no()));
 
   if (!recovery)
   {
-    ut_d(auto f=) zip.fix.fetch_sub(ibuf_may_exist
-                                    ? READ_FIX - IBUF_EXIST
-                                    : READ_FIX - UNFIXED);
+    ut_d(auto f=) zip.fix.fetch_sub(READ_FIX - UNFIXED);
     ut_ad(f >= READ_FIX);
     ut_ad(f < WRITE_FIX);
   }
-  else if (ibuf_may_exist)
-    set_ibuf_exist();
 
   lock.x_unlock(true);
 
diff --git a/storage/innobase/buf/buf0flu.cc b/storage/innobase/buf/buf0flu.cc
index d71cbfbf743..99b44c0d06e 100644
--- a/storage/innobase/buf/buf0flu.cc
+++ b/storage/innobase/buf/buf0flu.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1995, 2017, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2013, 2022, MariaDB Corporation.
+Copyright (c) 2013, 2023, MariaDB Corporation.
 Copyright (c) 2013, 2014, Fusion-io
 
 This program is free software; you can redistribute it and/or modify it under
@@ -889,7 +889,7 @@ static bool buf_flush_check_neighbor(const page_id_t id, ulint fold, bool lru)
   const buf_page_t *bpage=
     buf_pool.page_hash.get(id, buf_pool.page_hash.cell_get(fold));
 
-  if (!bpage || buf_pool.watch_is_sentinel(*bpage))
+  if (!bpage)
     return false;
 
   /* We avoid flushing 'non-old' blocks in an LRU flush, because the
@@ -1066,8 +1066,7 @@ static ulint buf_flush_try_neighbors(fil_space_t *space,
       because the flushed blocks are soon freed */
       if (!lru || id == page_id || bpage->is_old())
       {
-        if (!buf_pool.watch_is_sentinel(*bpage) &&
-            bpage->oldest_modification() > 1 && bpage->ready_for_flush() &&
+        if (bpage->oldest_modification() > 1 && bpage->ready_for_flush() &&
             bpage->flush(lru, space))
         {
           ++count;
@@ -1174,7 +1173,7 @@ static void buf_flush_discard_page(buf_page_t *bpage)
 
   ut_d(const auto state= bpage->state());
   ut_ad(state == buf_page_t::FREED || state == buf_page_t::UNFIXED ||
-        state == buf_page_t::IBUF_EXIST || state == buf_page_t::REINIT);
+        state == buf_page_t::REINIT);
   bpage->lock.u_unlock();
 
   buf_LRU_free_page(bpage, true);
diff --git a/storage/innobase/buf/buf0rea.cc b/storage/innobase/buf/buf0rea.cc
index 4a2ac88d97c..731f8a6c7e7 100644
--- a/storage/innobase/buf/buf0rea.cc
+++ b/storage/innobase/buf/buf0rea.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1995, 2017, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2015, 2022, MariaDB Corporation.
+Copyright (c) 2015, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -35,7 +35,7 @@ Created 11/5/1995 Heikki Tuuri
 #include "buf0lru.h"
 #include "buf0buddy.h"
 #include "buf0dblwr.h"
-#include "ibuf0ibuf.h"
+#include "page0zip.h"
 #include "log0recv.h"
 #include "trx0sys.h"
 #include "os0file.h"
@@ -48,74 +48,24 @@ read-ahead is not done: this is to prevent flooding the buffer pool with
 i/o-fixed buffer blocks */
 #define BUF_READ_AHEAD_PEND_LIMIT	2
 
-/** Remove the sentinel block for the watch before replacing it with a
-real block. watch_unset() or watch_occurred() will notice
-that the block has been replaced with the real block.
-@param w          sentinel
-@param chain      locked hash table chain
-@return           w->state() */
-inline uint32_t buf_pool_t::watch_remove(buf_page_t *w,
-                                         buf_pool_t::hash_chain &chain)
-{
-  mysql_mutex_assert_owner(&buf_pool.mutex);
-  ut_ad(xtest() || page_hash.lock_get(chain).is_write_locked());
-  ut_ad(w >= &watch[0]);
-  ut_ad(w < &watch[array_elements(watch)]);
-  ut_ad(!w->in_zip_hash);
-  ut_ad(!w->zip.data);
-
-  uint32_t s{w->state()};
-  w->set_state(buf_page_t::NOT_USED);
-  ut_ad(s >= buf_page_t::UNFIXED);
-  ut_ad(s < buf_page_t::READ_FIX);
-
-  if (~buf_page_t::LRU_MASK & s)
-    page_hash.remove(chain, w);
-
-  ut_ad(!w->in_page_hash);
-  w->id_= page_id_t(~0ULL);
-  return s;
-}
-
 /** Initialize a page for read to the buffer buf_pool. If the page is
 (1) already in buf_pool, or
-(2) if we specify to read only ibuf pages and the page is not an ibuf page, or
-(3) if the space is deleted or being deleted,
+(2) if the tablespace has been or is being deleted,
 then this function does nothing.
 Sets the io_fix flag to BUF_IO_READ and sets a non-recursive exclusive lock
 on the buffer frame. The io-handler must take care that the flag is cleared
 and the lock released later.
-@param[in]	mode			BUF_READ_IBUF_PAGES_ONLY, ...
 @param[in]	page_id			page id
 @param[in]	zip_size		ROW_FORMAT=COMPRESSED page size, or 0
-@param[in]	unzip			whether the uncompressed page is
-					requested (for ROW_FORMAT=COMPRESSED)
 @return pointer to the block
 @retval	NULL	in case of an error */
 TRANSACTIONAL_TARGET
-static buf_page_t* buf_page_init_for_read(ulint mode, const page_id_t page_id,
-                                          ulint zip_size, bool unzip)
+static buf_page_t* buf_page_init_for_read(const page_id_t page_id,
+                                          ulint zip_size)
 {
-  mtr_t mtr;
-
-  if (mode == BUF_READ_IBUF_PAGES_ONLY)
-  {
-    /* It is a read-ahead within an ibuf routine */
-    ut_ad(!ibuf_bitmap_page(page_id, zip_size));
-    ibuf_mtr_start(&mtr);
-
-    if (!recv_no_ibuf_operations && !ibuf_page(page_id, zip_size, &mtr))
-    {
-      ibuf_mtr_commit(&mtr);
-      return nullptr;
-    }
-  }
-  else
-    ut_ad(mode == BUF_READ_ANY_PAGE);
-
   buf_page_t *bpage= nullptr;
   buf_block_t *block= nullptr;
-  if (!zip_size || unzip || recv_recovery_is_on())
+  if (!zip_size || recv_recovery_is_on())
   {
     block= buf_LRU_get_free_block(false);
     block->initialise(page_id, zip_size, buf_page_t::READ_FIX);
@@ -128,8 +78,7 @@ static buf_page_t* buf_page_init_for_read(ulint mode, const page_id_t page_id,
 
   mysql_mutex_lock(&buf_pool.mutex);
 
-  buf_page_t *hash_page= buf_pool.page_hash.get(page_id, chain);
-  if (hash_page && !buf_pool.watch_is_sentinel(*hash_page))
+  if (buf_pool.page_hash.get(page_id, chain))
   {
     /* The page is already in the buffer pool. */
     if (block)
@@ -149,11 +98,6 @@ static buf_page_t* buf_page_init_for_read(ulint mode, const page_id_t page_id,
     {
       transactional_lock_guard<page_hash_latch> g
         {buf_pool.page_hash.lock_get(chain)};
-
-      if (hash_page)
-        bpage->set_state(buf_pool.watch_remove(hash_page, chain) +
-                         (buf_page_t::READ_FIX - buf_page_t::UNFIXED));
-
       buf_pool.page_hash.append(chain, &block->page);
     }
 
@@ -191,9 +135,7 @@ static buf_page_t* buf_page_init_for_read(ulint mode, const page_id_t page_id,
     check the page_hash again, as it may have been modified. */
     if (UNIV_UNLIKELY(lru))
     {
-      hash_page= buf_pool.page_hash.get(page_id, chain);
-
-      if (UNIV_UNLIKELY(hash_page && !buf_pool.watch_is_sentinel(*hash_page)))
+      if (UNIV_LIKELY_NULL(buf_pool.page_hash.get(page_id, chain)))
       {
         /* The block was added by some other thread. */
         buf_buddy_free(data, zip_size);
@@ -213,11 +155,6 @@ static buf_page_t* buf_page_init_for_read(ulint mode, const page_id_t page_id,
     {
       transactional_lock_guard<page_hash_latch> g
         {buf_pool.page_hash.lock_get(chain)};
-
-      if (hash_page)
-        bpage->set_state(buf_pool.watch_remove(hash_page, chain) +
-                         (buf_page_t::READ_FIX - buf_page_t::UNFIXED));
-
       buf_pool.page_hash.append(chain, bpage);
     }
 
@@ -228,13 +165,9 @@ static buf_page_t* buf_page_init_for_read(ulint mode, const page_id_t page_id,
 
   mysql_mutex_unlock(&buf_pool.mutex);
   buf_pool.n_pend_reads++;
-  goto func_exit_no_mutex;
+  return bpage;
 func_exit:
   mysql_mutex_unlock(&buf_pool.mutex);
-func_exit_no_mutex:
-  if (mode == BUF_READ_IBUF_PAGES_ONLY)
-    ibuf_mtr_commit(&mtr);
-
   ut_ad(!bpage || bpage->in_file());
 
   return bpage;
@@ -250,10 +183,8 @@ flag is cleared and the x-lock released by an i/o-handler thread.
 			to read from a non-existent tablespace
 @param[in,out] space	tablespace
 @param[in] sync		true if synchronous aio is desired
-@param[in] mode		BUF_READ_IBUF_PAGES_ONLY, ...,
 @param[in] page_id	page id
 @param[in] zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@param[in] unzip	true=request uncompressed page
 @return whether a read request was queued */
 static
 bool
@@ -261,10 +192,8 @@ buf_read_page_low(
 	dberr_t*		err,
 	fil_space_t*		space,
 	bool			sync,
-	ulint			mode,
 	const page_id_t		page_id,
-	ulint			zip_size,
-	bool			unzip)
+	ulint			zip_size)
 {
 	buf_page_t*	bpage;
 
@@ -279,25 +208,11 @@ nothing_read:
 		return false;
 	}
 
-	if (sync) {
-	} else if (trx_sys_hdr_page(page_id)
-		   || ibuf_bitmap_page(page_id, zip_size)
-		   || (!recv_no_ibuf_operations
-		       && ibuf_page(page_id, zip_size, nullptr))) {
-
-		/* Trx sys header is so low in the latching order that we play
-		safe and do not leave the i/o-completion to an asynchronous
-		i/o-thread. Change buffer pages must always be read with
-		synchronous i/o, to make sure they do not get involved in
-		thread deadlocks. */
-		sync = true;
-	}
-
 	/* The following call will also check if the tablespace does not exist
 	or is being dropped; if we succeed in initing the page in the buffer
 	pool for read, then DISCARD cannot proceed until the read has
 	completed */
-	bpage = buf_page_init_for_read(mode, page_id, zip_size, unzip);
+	bpage = buf_page_init_for_read(page_id, zip_size);
 
 	if (bpage == NULL) {
 		goto nothing_read;
@@ -311,7 +226,7 @@ nothing_read:
 
 	DBUG_LOG("ib_buf",
 		 "read page " << page_id << " zip_size=" << zip_size
-		 << " unzip=" << unzip << ',' << (sync ? "sync" : "async"));
+		 << (sync ? " sync" : " async"));
 
 	void* dst = zip_size ? bpage->zip.data : bpage->frame;
 	const ulint len = zip_size ? zip_size : srv_page_size;
@@ -339,22 +254,15 @@ nothing_read:
 /** Applies a random read-ahead in buf_pool if there are at least a threshold
 value of accessed pages from the random read-ahead area. Does not read any
 page, not even the one at the position (space, offset), if the read-ahead
-mechanism is not activated. NOTE 1: the calling thread may own latches on
+mechanism is not activated. NOTE: the calling thread may own latches on
 pages: to avoid deadlocks this function must be written such that it cannot
-end up waiting for these latches! NOTE 2: the calling thread must want
-access to the page given: this rule is set to prevent unintended read-aheads
-performed by ibuf routines, a situation which could result in a deadlock if
-the OS does not support asynchronous i/o.
+end up waiting for these latches!
 @param[in]	page_id		page id of a page which the current thread
 wants to access
 @param[in]	zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@param[in]	ibuf		whether we are inside ibuf routine
-@return number of page read requests issued; NOTE that if we read ibuf
-pages, it may happen that the page at the given page number does not
-get read even if we return a positive value! */
+@return number of page read requests issued */
 TRANSACTIONAL_TARGET
-ulint
-buf_read_ahead_random(const page_id_t page_id, ulint zip_size, bool ibuf)
+ulint buf_read_ahead_random(const page_id_t page_id, ulint zip_size)
 {
   if (!srv_random_read_ahead)
     return 0;
@@ -363,11 +271,6 @@ buf_read_ahead_random(const page_id_t page_id, ulint zip_size, bool ibuf)
     /* No read-ahead to avoid thread deadlocks */
     return 0;
 
-  if (ibuf_bitmap_page(page_id, zip_size) || trx_sys_hdr_page(page_id))
-    /* If it is an ibuf bitmap page or trx sys hdr, we do no
-    read-ahead, as that could break the ibuf page access order */
-    return 0;
-
   if (buf_pool.n_pend_reads > buf_pool.curr_size / BUF_READ_AHEAD_PEND_LIMIT)
     return 0;
 
@@ -403,17 +306,14 @@ read_ahead:
     goto no_read_ahead;
 
   /* Read all the suitable blocks within the area */
-  const ulint ibuf_mode= ibuf ? BUF_READ_IBUF_PAGES_ONLY : BUF_READ_ANY_PAGE;
 
   for (page_id_t i= low; i < high; ++i)
   {
-    if (ibuf_bitmap_page(i, zip_size))
-      continue;
     if (space->is_stopping())
       break;
     dberr_t err;
     space->reacquire();
-    if (buf_read_page_low(&err, space, false, ibuf_mode, i, zip_size, false))
+    if (buf_read_page_low(&err, space, false, i, zip_size))
       count++;
   }
 
@@ -454,8 +354,7 @@ dberr_t buf_read_page(const page_id_t page_id, ulint zip_size)
   }
 
   dberr_t err;
-  if (buf_read_page_low(&err, space, true, BUF_READ_ANY_PAGE,
-			page_id, zip_size, false))
+  if (buf_read_page_low(&err, space, true, page_id, zip_size))
     srv_stats.buf_pool_reads.add(1);
 
   buf_LRU_stat_inc_io();
@@ -474,8 +373,7 @@ void buf_read_page_background(fil_space_t *space, const page_id_t page_id,
 {
 	dberr_t		err;
 
-	if (buf_read_page_low(&err, space, false, BUF_READ_ANY_PAGE,
-			      page_id, zip_size, false)) {
+	if (buf_read_page_low(&err, space, false, page_id, zip_size)) {
 		srv_stats.buf_pool_reads.add(1);
 	}
 
@@ -506,16 +404,11 @@ only very improbably.
 NOTE 2: the calling thread may own latches on pages: to avoid deadlocks this
 function must be written such that it cannot end up waiting for these
 latches!
-NOTE 3: the calling thread must want access to the page given: this rule is
-set to prevent unintended read-aheads performed by ibuf routines, a situation
-which could result in a deadlock if the OS does not support asynchronous io.
 @param[in]	page_id		page id; see NOTE 3 above
 @param[in]	zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@param[in]	ibuf		whether if we are inside ibuf routine
 @return number of page read requests issued */
 TRANSACTIONAL_TARGET
-ulint
-buf_read_ahead_linear(const page_id_t page_id, ulint zip_size, bool ibuf)
+ulint buf_read_ahead_linear(const page_id_t page_id, ulint zip_size)
 {
   /* check if readahead is disabled */
   if (!srv_read_ahead_threshold)
@@ -540,11 +433,6 @@ buf_read_ahead_linear(const page_id_t page_id, ulint zip_size, bool ibuf)
     /* This is not a border page of the area */
     return 0;
 
-  if (ibuf_bitmap_page(page_id, zip_size) || trx_sys_hdr_page(page_id))
-    /* If it is an ibuf bitmap page or trx sys hdr, we do no
-    read-ahead, as that could break the ibuf page access order */
-    return 0;
-
   fil_space_t *space= fil_space_t::get(page_id.space());
   if (!space)
     return 0;
@@ -628,17 +516,13 @@ failed:
 
   /* If we got this far, read-ahead can be sensible: do it */
   count= 0;
-  for (ulint ibuf_mode= ibuf ? BUF_READ_IBUF_PAGES_ONLY : BUF_READ_ANY_PAGE;
-       new_low != new_high_1; ++new_low)
+  for (; new_low != new_high_1; ++new_low)
   {
-    if (ibuf_bitmap_page(new_low, zip_size))
-      continue;
     if (space->is_stopping())
       break;
     dberr_t err;
     space->reacquire();
-    count+= buf_read_page_low(&err, space, false, ibuf_mode, new_low, zip_size,
-                              false);
+    count+= buf_read_page_low(&err, space, false, new_low, zip_size);
   }
 
   if (count)
@@ -706,9 +590,7 @@ void buf_read_recv_pages(uint32_t space_id, st_::span<uint32_t> page_nos)
 
 		dberr_t err;
 		space->reacquire();
-		buf_read_page_low(&err, space, false,
-				  BUF_READ_ANY_PAGE, cur_page_id, zip_size,
-				  true);
+		buf_read_page_low(&err, space, false, cur_page_id, zip_size);
 
 		if (err != DB_SUCCESS) {
 			sql_print_error("InnoDB: Recovery failed to read page "
diff --git a/storage/innobase/data/data0type.cc b/storage/innobase/data/data0type.cc
index b1952bcc2a4..dc1c4b9a04a 100644
--- a/storage/innobase/data/data0type.cc
+++ b/storage/innobase/data/data0type.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2015, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2019, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -33,13 +33,6 @@ const byte reset_trx_id[DATA_TRX_ID_LEN + DATA_ROLL_PTR_LEN] = {
 	0x80, 0, 0, 0, 0, 0, 0
 };
 
-/* At the database startup we store the default-charset collation number of
-this MySQL installation to this global variable. If we have < 4.1.2 format
-column definitions, or records in the insert buffer, we use this
-charset-collation code for them. */
-
-ulint	data_mysql_default_charset_coll;
-
 /*********************************************************************//**
 Determine how many bytes the first n characters of the given string occupy.
 If the string is shorter than n characters, returns the number of bytes
diff --git a/storage/innobase/dict/dict0boot.cc b/storage/innobase/dict/dict0boot.cc
index 5516bce920b..8d18b37f132 100644
--- a/storage/innobase/dict/dict0boot.cc
+++ b/storage/innobase/dict/dict0boot.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2017, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2016, 2022, MariaDB Corporation.
+Copyright (c) 2016, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -30,7 +30,6 @@ Created 4/18/1996 Heikki Tuuri
 #include "dict0load.h"
 #include "trx0trx.h"
 #include "srv0srv.h"
-#include "ibuf0ibuf.h"
 #include "buf0flu.h"
 #include "log0recv.h"
 #include "os0file.h"
@@ -233,12 +232,12 @@ dberr_t dict_boot()
 	dict_sys.create();
 
 	dberr_t err;
-	const buf_block_t *d = buf_page_get_gen(hdr_page_id, 0, RW_X_LATCH,
+	const buf_block_t *d = buf_page_get_gen(hdr_page_id, 0, RW_S_LATCH,
 						nullptr, BUF_GET, &mtr, &err);
-        if (!d) {
+	if (!d) {
 		mtr.commit();
 		return err;
-        }
+	}
 
 	heap = mem_heap_create(450);
 
@@ -420,10 +419,7 @@ dberr_t dict_boot()
 
 	mtr.commit();
 
-	err = ibuf_init_at_db_start();
-
-	if (err == DB_SUCCESS || srv_force_recovery >= SRV_FORCE_NO_DDL_UNDO) {
-		err = DB_SUCCESS;
+	if (err == DB_SUCCESS) {
 		/* Load definitions of other indexes on system tables */
 
 		dict_load_sys_table(dict_sys.sys_tables);
diff --git a/storage/innobase/dict/dict0defrag_bg.cc b/storage/innobase/dict/dict0defrag_bg.cc
index ea2914e52dc..964e75aacc1 100644
--- a/storage/innobase/dict/dict0defrag_bg.cc
+++ b/storage/innobase/dict/dict0defrag_bg.cc
@@ -1,6 +1,6 @@
 /*****************************************************************************
 
-Copyright (c) 2016, 2022, MariaDB Corporation.
+Copyright (c) 2016, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -214,9 +214,6 @@ Save defragmentation result.
 @return DB_SUCCESS or error code */
 dberr_t dict_stats_save_defrag_summary(dict_index_t *index, THD *thd)
 {
-  if (index->is_ibuf())
-    return DB_SUCCESS;
-
   MDL_ticket *mdl_table= nullptr, *mdl_index= nullptr;
   dict_table_t *table_stats= dict_table_open_on_name(TABLE_STATS_NAME, false,
                                                      DICT_ERR_IGNORE_NONE);
@@ -336,8 +333,6 @@ dict_stats_save_defrag_stats(
 /*============================*/
 	dict_index_t*	index)	/*!< in: index */
 {
-  if (index->is_ibuf())
-    return DB_SUCCESS;
   if (!index->is_readable())
     return dict_stats_report_error(index->table, true);
 
diff --git a/storage/innobase/dict/dict0dict.cc b/storage/innobase/dict/dict0dict.cc
index e90dff03e16..c1c911480dd 100644
--- a/storage/innobase/dict/dict0dict.cc
+++ b/storage/innobase/dict/dict0dict.cc
@@ -2,7 +2,7 @@
 
 Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2012, Facebook Inc.
-Copyright (c) 2013, 2022, MariaDB Corporation.
+Copyright (c) 2013, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -1999,7 +1999,6 @@ dict_index_add_to_cache(
 	ut_ad(index->n_def == index->n_fields);
 	ut_ad(index->magic_n == DICT_INDEX_MAGIC_N);
 	ut_ad(!dict_index_is_online_ddl(index));
-	ut_ad(!dict_index_is_ibuf(index));
 
 	ut_d(mem_heap_validate(index->heap));
 	ut_a(!dict_index_is_clust(index)
@@ -2381,15 +2380,7 @@ dict_index_copy_types(
 	ulint			n_fields)	/*!< in: number of
 						field types to copy */
 {
-	ulint		i;
-
-	if (dict_index_is_ibuf(index)) {
-		dtuple_set_types_binary(tuple, n_fields);
-
-		return;
-	}
-
-	for (i = 0; i < n_fields; i++) {
+	for (ulint i = 0; i < n_fields; i++) {
 		const dict_field_t*	ifield;
 		dtype_t*		dfield_type;
 
@@ -2628,17 +2619,14 @@ dict_index_build_internal_non_clust(
 	ulint		i;
 	ibool*		indexed;
 
-	ut_ad(table && index);
-	ut_ad(!dict_index_is_clust(index));
-	ut_ad(!dict_index_is_ibuf(index));
+	ut_ad(!index->is_primary());
 	ut_ad(dict_sys.locked());
 
 	/* The clustered index should be the first in the list of indexes */
 	clust_index = UT_LIST_GET_FIRST(table->indexes);
 
 	ut_ad(clust_index);
-	ut_ad(dict_index_is_clust(clust_index));
-	ut_ad(!dict_index_is_ibuf(clust_index));
+	ut_ad(clust_index->is_clust());
 
 	/* Create a new index */
 	new_index = dict_mem_index_create(
@@ -3769,24 +3757,7 @@ dict_index_build_node_ptr(
 	dtuple_t*	tuple;
 	dfield_t*	field;
 	byte*		buf;
-	ulint		n_unique;
-
-	if (dict_index_is_ibuf(index)) {
-		/* In a universal index tree, we take the whole record as
-		the node pointer if the record is on the leaf level,
-		on non-leaf levels we remove the last field, which
-		contains the page number of the child page */
-
-		ut_a(!dict_table_is_comp(index->table));
-		n_unique = rec_get_n_fields_old(rec);
-
-		if (level > 0) {
-			ut_a(n_unique > 1);
-			n_unique--;
-		}
-	} else {
-		n_unique = dict_index_get_n_unique_in_tree_nonleaf(index);
-	}
+	ulint n_unique = dict_index_get_n_unique_in_tree_nonleaf(index);
 
 	tuple = dtuple_create(heap, n_unique + 1);
 
diff --git a/storage/innobase/dict/dict0load.cc b/storage/innobase/dict/dict0load.cc
index 1ee10ec8232..b442e926648 100644
--- a/storage/innobase/dict/dict0load.cc
+++ b/storage/innobase/dict/dict0load.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2016, 2022, MariaDB Corporation.
+Copyright (c) 2016, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -865,9 +865,7 @@ err_exit:
 	return READ_OK;
 }
 
-/** Check each tablespace found in the data dictionary.
-Then look at each table defined in SYS_TABLES that has a space_id > 0
-to find all the file-per-table tablespaces.
+/** Open each tablespace found in the data dictionary.
 
 In a crash recovery we already have some tablespace objects created from
 processing the REDO log. We will compare the
@@ -876,14 +874,12 @@ tablespace file. In addition, more validation will be done if recovery
 was needed and force_recovery is not set.
 
 We also scan the biggest space id, and store it to fil_system. */
-void dict_check_tablespaces_and_store_max_id()
+void dict_load_tablespaces()
 {
 	uint32_t	max_space_id = 0;
 	btr_pcur_t	pcur;
 	mtr_t		mtr;
 
-	DBUG_ENTER("dict_check_tablespaces_and_store_max_id");
-
 	mtr.start();
 
 	dict_sys.lock(SRW_LOCK_CALL);
@@ -976,8 +972,6 @@ void dict_check_tablespaces_and_store_max_id()
 	fil_set_max_space_id_if_bigger(max_space_id);
 
 	dict_sys.unlock();
-
-	DBUG_VOID_RETURN;
 }
 
 /** Error message for a delete-marked record in dict_load_column_low() */
@@ -1125,7 +1119,7 @@ err_len:
 
 			prtype = dtype_form_prtype(
 				prtype,
-				data_mysql_default_charset_coll);
+				default_charset_info->number);
 		}
 	}
 
diff --git a/storage/innobase/dict/dict0stats.cc b/storage/innobase/dict/dict0stats.cc
index 06d30515229..ce02d9513d1 100644
--- a/storage/innobase/dict/dict0stats.cc
+++ b/storage/innobase/dict/dict0stats.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2009, 2019, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2015, 2022, MariaDB Corporation.
+Copyright (c) 2015, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -584,8 +584,6 @@ dict_stats_table_clone_create(
 			continue;
 		}
 
-		ut_ad(!dict_index_is_ibuf(index));
-
 		ulint	n_uniq = dict_index_get_n_unique(index);
 
 		heap_size += sizeof(dict_index_t);
@@ -634,8 +632,6 @@ dict_stats_table_clone_create(
 			continue;
 		}
 
-		ut_ad(!dict_index_is_ibuf(index));
-
 		dict_index_t*	idx;
 
 		idx = (dict_index_t*) mem_heap_zalloc(heap, sizeof(*idx));
@@ -714,7 +710,6 @@ dict_stats_empty_index(
 				/*!< in: whether to empty defrag stats */
 {
 	ut_ad(!(index->type & DICT_FTS));
-	ut_ad(!dict_index_is_ibuf(index));
 	ut_ad(index->table->stats_mutex_is_owner());
 
 	ulint	n_uniq = index->n_uniq;
@@ -767,8 +762,6 @@ dict_stats_empty_table(
 			continue;
 		}
 
-		ut_ad(!dict_index_is_ibuf(index));
-
 		dict_stats_empty_index(index, empty_defrag_stats);
 	}
 
@@ -901,8 +894,6 @@ dict_stats_copy(
 			}
 		}
 
-		ut_ad(!dict_index_is_ibuf(dst_idx));
-
 		if (!INDEX_EQ(src_idx, dst_idx)) {
 			for (src_idx = dict_table_get_first_index(src);
 			     src_idx != NULL;
@@ -1094,11 +1085,10 @@ btr_cur_t::open_random_leaf(rec_offs *&offsets, mem_heap_t *&heap, mtr_t &mtr)
 
   dberr_t err;
   auto offset= index()->page;
-  bool merge= false;
   ulint height= ULINT_UNDEFINED;
 
   while (buf_block_t *block=
-         btr_block_get(*index(), offset, RW_S_LATCH, merge, &mtr, &err))
+         btr_block_get(*index(), offset, RW_S_LATCH, &mtr, &err))
   {
     page_cur.block= block;
 
@@ -1120,8 +1110,7 @@ btr_cur_t::open_random_leaf(rec_offs *&offsets, mem_heap_t *&heap, mtr_t &mtr)
       return DB_SUCCESS;
     }
 
-    if (!--height)
-      merge= !index()->is_clust();
+    height--;
 
     page_cur_open_on_rnd_user_rec(&page_cur);
 
@@ -1462,10 +1451,6 @@ dummy_empty:
 		dict_stats_empty_index(index, false);
 		index->table->stats_mutex_unlock();
 		return err;
-#if defined UNIV_DEBUG || defined UNIV_IBUF_DEBUG
-	} else if (ibuf_debug && !dict_index_is_clust(index)) {
-		goto dummy_empty;
-#endif /* UNIV_DEBUG || UNIV_IBUF_DEBUG */
 	} else if (dict_index_is_online_ddl(index) || !index->is_committed()
 		   || !index->table->space) {
 		goto dummy_empty;
@@ -1571,9 +1556,6 @@ empty_table:
 	}
 
 	for (; index != NULL; index = dict_table_get_next_index(index)) {
-
-		ut_ad(!dict_index_is_ibuf(index));
-
 		if (!index->is_btree()) {
 			continue;
 		}
@@ -1638,9 +1620,7 @@ static dberr_t page_cur_open_level(page_cur_t *page_cur, ulint level,
 
   for (ulint height = ULINT_UNDEFINED;; height--)
   {
-    buf_block_t* block=
-      btr_block_get(*index, page, RW_S_LATCH,
-                    !height && !index->is_clust(), mtr, &err);
+    buf_block_t* block= btr_block_get(*index, page, RW_S_LATCH, mtr, &err);
     if (!block)
       break;
 
@@ -2258,9 +2238,7 @@ dict_stats_analyze_index_below_cur(
 
 		block = buf_page_get_gen(page_id, zip_size,
 					 RW_S_LATCH, NULL, BUF_GET,
-					 &mtr, &err,
-					 !index->is_clust()
-					 && 1 == btr_page_get_level(page));
+					 &mtr, &err);
 		if (!block) {
 			goto func_exit;
 		}
@@ -2999,7 +2977,6 @@ dict_stats_update_persistent(
 		return(DB_CORRUPTION);
 	}
 
-	ut_ad(!dict_index_is_ibuf(index));
 	table->stats_mutex_lock();
 	dict_stats_empty_index(index, false);
 	table->stats_mutex_unlock();
@@ -3373,8 +3350,6 @@ unlocked_free_and_exit:
 			continue;
 		}
 
-		ut_ad(!dict_index_is_ibuf(index));
-
 		for (unsigned i = 0; i < index->n_uniq; i++) {
 
 			char	stat_name[16];
diff --git a/storage/innobase/fil/fil0fil.cc b/storage/innobase/fil/fil0fil.cc
index cecda94cac4..bde04c84de6 100644
--- a/storage/innobase/fil/fil0fil.cc
+++ b/storage/innobase/fil/fil0fil.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1995, 2021, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2014, 2022, MariaDB Corporation.
+Copyright (c) 2014, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -45,7 +45,6 @@ Created 10/25/1995 Heikki Tuuri
 #include "srv0start.h"
 #include "trx0purge.h"
 #include "buf0lru.h"
-#include "ibuf0ibuf.h"
 #include "buf0flu.h"
 #include "log.h"
 #ifdef __linux__
@@ -1414,7 +1413,7 @@ void fil_system_t::set_write_through(bool write_through)
 {
   mysql_mutex_lock(&mutex);
 
-  if (write_through != this->write_through)
+  if (write_through != is_write_through())
   {
     this->write_through= write_through;
     fil_space_t::reopen_all();
@@ -1427,7 +1426,7 @@ void fil_system_t::set_buffered(bool buffered)
 {
   mysql_mutex_lock(&mutex);
 
-  if (buffered != this->buffered)
+  if (buffered != is_buffered())
   {
     this->buffered= buffered;
     fil_space_t::reopen_all();
@@ -1718,7 +1717,6 @@ pfs_os_file_t fil_delete_tablespace(uint32_t id)
     fil_space_free_low(space);
   }
 
-  ibuf_delete_for_discarded_space(id);
   return handle;
 }
 
@@ -2859,10 +2857,6 @@ write_completed:
   {
     ut_ad(request.is_read());
 
-    /* IMPORTANT: since i/o handling for reads will read also the insert
-    buffer in fil_system.sys_space, we have to be very careful not to
-    introduce deadlocks. We never close fil_system.sys_space data
-    files and never issue asynchronous reads of change buffer pages. */
     const page_id_t id(request.bpage->id());
 
     if (dberr_t err= request.bpage->read_complete(*request.node))
diff --git a/storage/innobase/fil/fil0pagecompress.cc b/storage/innobase/fil/fil0pagecompress.cc
index b6971558201..bdc08b22f3a 100644
--- a/storage/innobase/fil/fil0pagecompress.cc
+++ b/storage/innobase/fil/fil0pagecompress.cc
@@ -1,6 +1,6 @@
 /*****************************************************************************
 
-Copyright (C) 2013, 2021, MariaDB Corporation.
+Copyright (C) 2013, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -47,7 +47,6 @@ Updated 14/02/2015
 #include "trx0sys.h"
 #include "row0mysql.h"
 #include "buf0lru.h"
-#include "ibuf0ibuf.h"
 #include "zlib.h"
 #ifdef __linux__
 #include <linux/fs.h>
diff --git a/storage/innobase/fsp/fsp0fsp.cc b/storage/innobase/fsp/fsp0fsp.cc
index 09583e157b7..a7b98e159cb 100644
--- a/storage/innobase/fsp/fsp0fsp.cc
+++ b/storage/innobase/fsp/fsp0fsp.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1995, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -33,7 +33,6 @@ Created 11/29/1995 Heikki Tuuri
 #include "page0page.h"
 #include "srv0srv.h"
 #include "srv0start.h"
-#include "ibuf0ibuf.h"
 #include "btr0btr.h"
 #include "btr0sea.h"
 #include "dict0boot.h"
@@ -848,11 +847,17 @@ fsp_fill_free_list(
       {
         buf_block_t *f= buf_LRU_get_free_block(false);
         buf_block_t *block=
-          buf_page_create(space,
-                          static_cast<uint32_t>(i + FSP_IBUF_BITMAP_OFFSET),
+          buf_page_create(space, static_cast<uint32_t>(i + 1),
                           zip_size, mtr, f);
         if (UNIV_UNLIKELY(block != f))
           buf_pool.free_block(f);
+        /* The zero-initialization will reset the change buffer bitmap bits
+        to safe values for possible import to an earlier version that
+        supports change buffering:
+
+        IBUF_BITMAP_FREE     = 0 (no space left for buffering inserts)
+        IBUF_BITMAP_BUFFERED = 0 (no changes have been buffered)
+        IBUF_BITMAP_IBUF     = 0 (not part of the change buffer) */
         fsp_init_file_page(space, block, mtr);
         mtr->write<2>(*block, FIL_PAGE_TYPE + block->page.frame,
                       FIL_PAGE_IBUF_BITMAP);
@@ -877,9 +882,9 @@ fsp_fill_free_list(
     if (UNIV_UNLIKELY(init_xdes))
     {
       /* The first page in the extent is a descriptor page and the
-      second is an ibuf bitmap page: mark them used */
+      second was reserved for change buffer bitmap: mark them used */
       xdes_set_free<false>(*xdes, descr, 0, mtr);
-      xdes_set_free<false>(*xdes, descr, FSP_IBUF_BITMAP_OFFSET, mtr);
+      xdes_set_free<false>(*xdes, descr, 1, mtr);
       xdes_set_state(*xdes, descr, XDES_FREE_FRAG, mtr);
       if (dberr_t err= flst_add_last(header, FSP_HEADER_OFFSET + FSP_FREE_FRAG,
                                      xdes, xoffset, mtr))
diff --git a/storage/innobase/gis/gis0rtree.cc b/storage/innobase/gis/gis0rtree.cc
index 59d77c9c5fc..28e8359cab4 100644
--- a/storage/innobase/gis/gis0rtree.cc
+++ b/storage/innobase/gis/gis0rtree.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2018, 2022, MariaDB Corporation.
+Copyright (c) 2018, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -34,7 +34,6 @@ Created 2013/03/27 Allen Lai and Jimmy Yang
 #include "btr0pcur.h"
 #include "rem0cmp.h"
 #include "lock0lock.h"
-#include "ibuf0ibuf.h"
 #include "trx0undo.h"
 #include "srv0mon.h"
 #include "gis0geo.h"
@@ -538,7 +537,7 @@ err_exit:
 	mem_heap_free(heap);
 }
 
-MY_ATTRIBUTE((nonnull, warn_unused_result))
+MY_ATTRIBUTE((nonnull(1,3,4,5,6,8), warn_unused_result))
 /**************************************************************//**
 Update parent page's MBR and Predicate lock information during a split */
 static
@@ -552,6 +551,7 @@ rtr_adjust_upper_level(
 	buf_block_t*	new_block,	/*!< in/out: the new half page */
 	rtr_mbr_t*	mbr,		/*!< in: MBR on the old page */
 	rtr_mbr_t*	new_mbr,	/*!< in: MBR on the new page */
+	que_thr_t*	thr,		/*!< in/out: query thread */
 	mtr_t*		mtr)		/*!< in: mtr */
 {
 	ulint		page_no;
@@ -570,7 +570,6 @@ rtr_adjust_upper_level(
 	/* Create a memory heap where the data tuple is stored */
 	heap = mem_heap_create(1024);
 
-	cursor.thr = sea_cur->thr;
 	cursor.page_cur.index = sea_cur->index();
 	cursor.page_cur.block = block;
 
@@ -584,7 +583,8 @@ rtr_adjust_upper_level(
 
 	/* Set new mbr for the old page on the upper level. */
 	/* Look up the index for the node pointer to page */
-	offsets = rtr_page_get_father_block(NULL, heap, mtr, sea_cur, &cursor);
+	offsets = rtr_page_get_father_block(nullptr, heap, sea_cur, &cursor,
+					    thr, mtr);
 
 	page_cursor = btr_cur_get_page_cur(&cursor);
 
@@ -669,7 +669,7 @@ rtr_adjust_upper_level(
 	if (next_page_no == FIL_NULL) {
 	} else if (buf_block_t*	next_block =
 		   btr_block_get(*sea_cur->index(), next_page_no, RW_X_LATCH,
-				 false, mtr, &err)) {
+				 mtr, &err)) {
 		if (UNIV_UNLIKELY(memcmp_aligned<4>(next_block->page.frame
 						    + FIL_PAGE_PREV,
 						    block->page.frame
@@ -691,11 +691,6 @@ rtr_adjust_upper_level(
 /*************************************************************//**
 Moves record list to another page for rtree splitting.
 
-IMPORTANT: The caller will have to update IBUF_BITMAP_FREE
-if new_block is a compressed leaf page in a secondary index.
-This has to be done either within the same mini-transaction,
-or by invoking ibuf_reset_free_bits() before mtr_commit().
-
 @return error code
 @retval DB_FAIL on ROW_FORMAT=COMPRESSED compression failure */
 static
@@ -731,8 +726,7 @@ rtr_split_page_move_rec_list(
 	ulint			max_to_move	= 0;
 	rtr_rec_move_t*		rec_move	= NULL;
 
-	ut_ad(!dict_index_is_ibuf(index));
-	ut_ad(dict_index_is_spatial(index));
+	ut_ad(index->is_spatial());
 
 	rec_offs_init(offsets_);
 
@@ -867,7 +861,8 @@ rtr_page_split_and_insert(
 	const dtuple_t*	tuple,	/*!< in: tuple to insert */
 	ulint		n_ext,	/*!< in: number of externally stored columns */
 	mtr_t*		mtr,	/*!< in: mtr */
-	dberr_t*	err)	/*!< out: error code */
+	dberr_t*	err,	/*!< out: error code */
+	que_thr_t*	thr)	/*!< in: query thread */
 {
 	buf_block_t*		block;
 	page_t*			page;
@@ -1159,7 +1154,7 @@ after_insert:
 
 	/* Adjust the upper level. */
 	*err = rtr_adjust_upper_level(cursor, flags, block, new_block,
-				      &mbr, &new_mbr, mtr);
+				      &mbr, &new_mbr, thr, mtr);
 	if (UNIV_UNLIKELY(*err != DB_SUCCESS)) {
 		return nullptr;
 	}
@@ -1179,13 +1174,6 @@ after_insert:
 	/* If the new res insert fail, we need to do another split
 	 again. */
 	if (!rec) {
-		/* We play safe and reset the free bits for new_page */
-		if (!dict_index_is_clust(cursor->index())
-		    && !cursor->index()->table->is_temporary()) {
-			ibuf_reset_free_bits(new_block);
-			ibuf_reset_free_bits(block);
-		}
-
 		/* We need to clean the parent path here and search father
 		node later, otherwise, it's possible that find a wrong
 		parent. */
@@ -1214,6 +1202,244 @@ after_insert:
 	return(rec);
 }
 
+/*************************************************************//**
+Makes tree one level higher by splitting the root, and inserts the tuple.
+NOTE that the operation of this function must always succeed,
+we cannot reverse it: therefore enough free disk space must be
+guaranteed to be available before this function is called.
+@return inserted record */
+rec_t*
+rtr_root_raise_and_insert(
+/*======================*/
+	ulint		flags,	/*!< in: undo logging and locking flags */
+	btr_cur_t*	cursor,	/*!< in: cursor at which to insert: must be
+				on the root page; when the function returns,
+				the cursor is positioned on the predecessor
+				of the inserted record */
+	rec_offs**	offsets,/*!< out: offsets on inserted record */
+	mem_heap_t**	heap,	/*!< in/out: pointer to memory heap, or NULL */
+	const dtuple_t*	tuple,	/*!< in: tuple to insert */
+	ulint		n_ext,	/*!< in: number of externally stored columns */
+	mtr_t*		mtr,	/*!< in: mtr */
+	dberr_t*	err,	/*!< out: error code */
+	que_thr_t*	thr)	/*!< in: query thread */
+{
+	dict_index_t*	index;
+	rec_t*		rec;
+	dtuple_t*	node_ptr;
+	ulint		level;
+	rec_t*		node_ptr_rec;
+	page_cur_t*	page_cursor;
+	page_zip_des_t*	root_page_zip;
+	page_zip_des_t*	new_page_zip;
+	buf_block_t*	root;
+	buf_block_t*	new_block;
+
+	root = btr_cur_get_block(cursor);
+	root_page_zip = buf_block_get_page_zip(root);
+	ut_ad(!page_is_empty(root->page.frame));
+	index = btr_cur_get_index(cursor);
+	ut_ad(index->is_spatial());
+#ifdef UNIV_ZIP_DEBUG
+	ut_a(!root_page_zip
+	     || page_zip_validate(root_page_zip, root->page.frame, index));
+#endif /* UNIV_ZIP_DEBUG */
+
+	const page_id_t root_id{root->page.id()};
+
+	ut_ad(mtr->memo_contains_flagged(&index->lock, MTR_MEMO_X_LOCK
+					 | MTR_MEMO_SX_LOCK));
+	ut_ad(mtr->memo_contains_flagged(root, MTR_MEMO_PAGE_X_FIX));
+
+	if (index->page != root_id.page_no()) {
+		ut_ad("corrupted root page number" == 0);
+		return nullptr;
+	}
+
+	if (!btr_root_fseg_validate(FIL_PAGE_DATA + PAGE_BTR_SEG_LEAF,
+				    *root, *index->table->space)
+	    || !btr_root_fseg_validate(FIL_PAGE_DATA + PAGE_BTR_SEG_TOP,
+				       *root, *index->table->space)) {
+		return nullptr;
+	}
+
+	/* Allocate a new page to the tree. Root splitting is done by first
+	moving the root records to the new page, emptying the root, putting
+	a node pointer to the new page, and then splitting the new page. */
+
+	level = btr_page_get_level(root->page.frame);
+
+	new_block = btr_page_alloc(index, 0, FSP_NO_DIR, level, mtr, mtr, err);
+
+	if (!new_block) {
+		return nullptr;
+	}
+
+	new_page_zip = buf_block_get_page_zip(new_block);
+	ut_a(!new_page_zip == !root_page_zip);
+	ut_a(!new_page_zip
+	     || page_zip_get_size(new_page_zip)
+	     == page_zip_get_size(root_page_zip));
+
+	btr_page_create(new_block, new_page_zip, index, level, mtr);
+	if (page_has_siblings(new_block->page.frame)) {
+		compile_time_assert(FIL_PAGE_NEXT == FIL_PAGE_PREV + 4);
+		compile_time_assert(FIL_NULL == 0xffffffff);
+		static_assert(FIL_PAGE_PREV % 8 == 0, "alignment");
+		memset_aligned<8>(new_block->page.frame + FIL_PAGE_PREV,
+				  0xff, 8);
+		mtr->memset(new_block, FIL_PAGE_PREV, 8, 0xff);
+		if (UNIV_LIKELY_NULL(new_page_zip)) {
+			memset_aligned<8>(new_page_zip->data + FIL_PAGE_PREV,
+					  0xff, 8);
+		}
+	}
+
+	/* Copy the records from root to the new page one by one. */
+	dberr_t e;
+	if (!err) {
+		err = &e;
+	}
+
+	if (0
+#ifdef UNIV_ZIP_COPY
+	    || new_page_zip
+#endif /* UNIV_ZIP_COPY */
+	    || !page_copy_rec_list_end(new_block, root,
+				       page_get_infimum_rec(root->page.frame),
+				       index, mtr, err)) {
+		switch (*err) {
+		case DB_SUCCESS:
+			break;
+		case DB_FAIL:
+			*err = DB_SUCCESS;
+			break;
+		default:
+			return nullptr;
+		}
+
+		ut_a(new_page_zip);
+
+		/* Copy the page byte for byte. */
+		page_zip_copy_recs(new_block, root_page_zip,
+				   root->page.frame, index, mtr);
+
+		/* Update the lock table and possible hash index. */
+		if (index->has_locking()) {
+			lock_move_rec_list_end(
+				new_block, root,
+				page_get_infimum_rec(root->page.frame));
+		}
+
+		/* Move any existing predicate locks */
+		lock_prdt_rec_move(new_block, root_id);
+	}
+
+	constexpr uint16_t max_trx_id = PAGE_HEADER + PAGE_MAX_TRX_ID;
+	if (!index->is_primary()) {
+		/* In secondary indexes,
+		PAGE_MAX_TRX_ID can be reset on the root page, because
+		the field only matters on leaf pages, and the root no
+		longer is a leaf page. (Older versions of InnoDB did
+		set PAGE_MAX_TRX_ID on all secondary index pages.) */
+		byte* p = my_assume_aligned<8>(
+			PAGE_HEADER + PAGE_MAX_TRX_ID + root->page.frame);
+		if (mach_read_from_8(p)) {
+			mtr->memset(root, max_trx_id, 8, 0);
+			if (UNIV_LIKELY_NULL(root->page.zip.data)) {
+				memset_aligned<8>(max_trx_id
+						  + root->page.zip.data, 0, 8);
+			}
+		}
+	} else {
+		/* PAGE_ROOT_AUTO_INC is only present in the clustered index
+		root page; on other clustered index pages, we want to reserve
+		the field PAGE_MAX_TRX_ID for future use. */
+		byte* p = my_assume_aligned<8>(
+			PAGE_HEADER + PAGE_MAX_TRX_ID + new_block->page.frame);
+		if (mach_read_from_8(p)) {
+			mtr->memset(new_block, max_trx_id, 8, 0);
+			if (UNIV_LIKELY_NULL(new_block->page.zip.data)) {
+				memset_aligned<8>(max_trx_id
+						  + new_block->page.zip.data,
+						  0, 8);
+			}
+		}
+	}
+
+	/* If this is a pessimistic insert which is actually done to
+	perform a pessimistic update then we have stored the lock
+	information of the record to be inserted on the infimum of the
+	root page: we cannot discard the lock structs on the root page */
+
+	if (index->has_locking()) {
+		lock_update_root_raise(*new_block, root_id);
+	}
+
+	/* Create a memory heap where the node pointer is stored */
+	if (!*heap) {
+		*heap = mem_heap_create(1000);
+	}
+
+	const uint32_t new_page_no = new_block->page.id().page_no();
+	rec = page_rec_get_next(page_get_infimum_rec(new_block->page.frame));
+	ut_ad(rec); /* We just created the page. */
+
+	/* Build the node pointer (= node key and page address) for the
+	child */
+	rtr_mbr_t new_mbr;
+	rtr_page_cal_mbr(index, new_block, &new_mbr, *heap);
+	node_ptr = rtr_index_build_node_ptr(index, &new_mbr, rec, new_page_no,
+					    *heap);
+	/* The node pointer must be marked as the predefined minimum record,
+	as there is no lower alphabetical limit to records in the leftmost
+	node of a level: */
+	dtuple_set_info_bits(node_ptr,
+			     dtuple_get_info_bits(node_ptr)
+			     | REC_INFO_MIN_REC_FLAG);
+
+	/* Rebuild the root page to get free space */
+	btr_page_empty(root, root_page_zip, index, level + 1, mtr);
+	ut_ad(!page_has_siblings(root->page.frame));
+
+	page_cursor = btr_cur_get_page_cur(cursor);
+
+	/* Insert node pointer to the root */
+
+	page_cur_set_before_first(root, page_cursor);
+
+	node_ptr_rec = page_cur_tuple_insert(page_cursor, node_ptr,
+					     offsets, heap, 0, mtr);
+
+	/* The root page should only contain the node pointer
+	to new_block at this point.  Thus, the data should fit. */
+	ut_a(node_ptr_rec);
+
+	page_cursor->block = new_block;
+	page_cursor->index = index;
+
+	if (tuple) {
+		ut_ad(dtuple_check_typed(tuple));
+		/* Reposition the cursor to the child node */
+		ulint low_match = 0, up_match = 0;
+
+		if (page_cur_search_with_match(tuple, PAGE_CUR_LE,
+					       &up_match, &low_match,
+					       page_cursor, nullptr)) {
+			if (err) {
+				*err = DB_CORRUPTION;
+			}
+			return nullptr;
+		}
+	} else {
+		page_cursor->rec = page_get_infimum_rec(new_block->page.frame);
+	}
+
+	/* Split the child and insert tuple */
+	return rtr_page_split_and_insert(flags, cursor, offsets, heap,
+					 tuple, n_ext, mtr, err, thr);
+}
+
 /****************************************************************//**
 Following the right link to find the proper block for insert.
 @return the proper block.*/
@@ -1242,6 +1468,7 @@ rtr_ins_enlarge_mbr(
 
 	/* Check path info is not empty. */
 	ut_ad(!btr_cur->rtr_info->parent_path->empty());
+	ut_ad(btr_cur->rtr_info->thr || !btr_cur->index()->is_committed());
 
 	/* Create a memory heap. */
 	heap = mem_heap_create(1024);
@@ -1267,7 +1494,8 @@ rtr_ins_enlarge_mbr(
 		cursor.page_cur.index = page_cursor->index;
 		cursor.page_cur.block = block;
 		offsets = rtr_page_get_father_block(
-			NULL, heap, mtr, btr_cur, &cursor);
+			nullptr, heap, btr_cur, &cursor,
+			btr_cur->rtr_info->thr, mtr);
 
 		page = buf_block_get_frame(block);
 
diff --git a/storage/innobase/gis/gis0sea.cc b/storage/innobase/gis/gis0sea.cc
index 207d49abeba..d3f991bb677 100644
--- a/storage/innobase/gis/gis0sea.cc
+++ b/storage/innobase/gis/gis0sea.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2016, 2018, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -34,7 +34,6 @@ Created 2014/01/16 Jimmy Yang
 #include "btr0pcur.h"
 #include "rem0cmp.h"
 #include "lock0lock.h"
-#include "ibuf0ibuf.h"
 #include "trx0trx.h"
 #include "srv0mon.h"
 #include "que0que.h"
@@ -511,13 +510,13 @@ static void rtr_compare_cursor_rec(const rec_t *rec, dict_index_t *index,
 
 /**************************************************************//**
 Initializes and opens a persistent cursor to an index tree. It should be
-closed with btr_pcur_close. Mainly called by row_search_index_entry() */
+closed with btr_pcur_close. */
 bool
 rtr_pcur_open(
-	dict_index_t*	index,	/*!< in: index */
 	const dtuple_t*	tuple,	/*!< in: tuple on which search done */
 	btr_latch_mode	latch_mode,/*!< in: BTR_SEARCH_LEAF, ... */
 	btr_pcur_t*	cursor, /*!< in: memory buffer for persistent cursor */
+	que_thr_t*	thr,	/*!< in/out; query thread */
 	mtr_t*		mtr)	/*!< in: mtr */
 {
 	static_assert(BTR_MODIFY_TREE == (8 | BTR_MODIFY_LEAF), "");
@@ -534,15 +533,16 @@ rtr_pcur_open(
 	/* Search with the tree cursor */
 
 	btr_cur_t* btr_cursor = btr_pcur_get_btr_cur(cursor);
-	btr_cursor->page_cur.index = index;
+	dict_index_t* const index = cursor->index();
 
-	btr_cursor->rtr_info = rtr_create_rtr_info(false, false,
-						   btr_cursor, index);
+	btr_cursor->rtr_info = rtr_create_rtr_info(false, false, thr,
+						   btr_cursor);
 
-	/* Purge will SX lock the tree instead of take Page Locks */
-	if (btr_cursor->thr) {
+	if (!thr) {
+		/*  Purge will U lock the tree instead of take Page Locks */
+	} else {
 		btr_cursor->rtr_info->need_page_lock = true;
-		btr_cursor->rtr_info->thr = btr_cursor->thr;
+		btr_cursor->rtr_info->thr = thr;
 	}
 
 	if ((latch_mode & 8) && index->lock.have_u_not_x()) {
@@ -607,12 +607,14 @@ rtr_pcur_open(
 				about parent nodes in search
 @param[out]	cursor		cursor on node pointer record,
 				its page x-latched
+@param[in,out]	thr		query thread
 @return whether the cursor was successfully positioned */
-bool rtr_page_get_father(mtr_t *mtr, btr_cur_t *sea_cur, btr_cur_t *cursor)
+bool rtr_page_get_father(mtr_t *mtr, btr_cur_t *sea_cur, btr_cur_t *cursor,
+                         que_thr_t *thr)
 {
   mem_heap_t *heap = mem_heap_create(100);
   rec_offs *offsets= rtr_page_get_father_block(nullptr, heap,
-                                               mtr, sea_cur, cursor);
+                                               sea_cur, cursor, thr, mtr);
   mem_heap_free(heap);
   return offsets != nullptr;
 }
@@ -629,12 +631,13 @@ static const rec_t* rtr_get_father_node(
 	btr_cur_t*	sea_cur,/*!< in: search cursor */
 	btr_cur_t*	btr_cur,/*!< in/out: tree cursor; the cursor page is
 				s- or x-latched, but see also above! */
+	que_thr_t*	thr,	/*!< in/out: query thread */
 	ulint		page_no,/*!< Current page no */
 	mtr_t*		mtr)	/*!< in: mtr */
 {
 	const rec_t* rec = nullptr;
 	auto had_rtr = btr_cur->rtr_info;
-	dict_index_t* const index = btr_cur->index();
+	ut_d(dict_index_t* const index = btr_cur->index());
 
 	/* Try to optimally locate the parent node. Level should always
 	less than sea_cur->tree_height unless the root is splitting */
@@ -666,7 +669,7 @@ static const rec_t* rtr_get_father_node(
 		rtr_clean_rtr_info(btr_cur->rtr_info, true);
 	}
 
-	btr_cur->rtr_info = rtr_create_rtr_info(false, false, btr_cur, index);
+	btr_cur->rtr_info = rtr_create_rtr_info(false, false, thr, btr_cur);
 
 	if (btr_cur_search_to_nth_level(level, tuple,
 					PAGE_CUR_RTREE_LOCATE,
@@ -718,6 +721,7 @@ rtr_page_get_father_node_ptr(
 	btr_cur_t*	cursor,	/*!< in: cursor pointing to user record,
 				out: cursor on node pointer record,
 				its page x-latched */
+	que_thr_t*	thr,	/*!< in/out: query thread */
 	mtr_t*		mtr)	/*!< in: mtr */
 {
 	dtuple_t*	tuple;
@@ -754,7 +758,7 @@ rtr_page_get_father_node_ptr(
 
 	const rec_t* node_ptr = rtr_get_father_node(level + 1, tuple,
 						    sea_cur, cursor,
-						    page_no, mtr);
+						    thr, page_no, mtr);
 	if (!node_ptr) {
 		return nullptr;
 	}
@@ -780,18 +784,20 @@ rtr_page_get_father_block(
 /*======================*/
 	rec_offs*	offsets,/*!< in: work area for the return value */
 	mem_heap_t*	heap,	/*!< in: memory heap to use */
-	mtr_t*		mtr,	/*!< in: mtr */
 	btr_cur_t*	sea_cur,/*!< in: search cursor, contains information
 				about parent nodes in search */
-	btr_cur_t*	cursor)	/*!< out: cursor on node pointer record,
+	btr_cur_t*	cursor,	/*!< out: cursor on node pointer record,
 				its page x-latched */
+	que_thr_t*	thr,	/*!< in/out: query thread */
+	mtr_t*		mtr)	/*!< in/out: mtr */
 {
   rec_t *rec=
     page_rec_get_next(page_get_infimum_rec(cursor->block()->page.frame));
   if (!rec)
     return nullptr;
   cursor->page_cur.rec= rec;
-  return rtr_page_get_father_node_ptr(offsets, heap, sea_cur, cursor, mtr);
+  return rtr_page_get_father_node_ptr(offsets, heap, sea_cur, cursor,
+                                      thr, mtr);
 }
 
 /*******************************************************************//**
@@ -804,12 +810,12 @@ rtr_create_rtr_info(
 	bool		init_matches,	/*!< in: Whether to initiate the
 					"matches" structure for collecting
 					matched leaf records */
-	btr_cur_t*	cursor,		/*!< in: tree search cursor */
-	dict_index_t*	index)		/*!< in: index struct */
+	que_thr_t*	thr,		/*!< in/out: query thread */
+	btr_cur_t*	cursor)		/*!< in: tree search cursor */
 {
 	rtr_info_t*	rtr_info;
 
-	index = index ? index : cursor->index();
+	dict_index_t* index = cursor->index();
 	ut_ad(index);
 
 	rtr_info = static_cast<rtr_info_t*>(ut_zalloc_nokey(sizeof(*rtr_info)));
@@ -817,6 +823,7 @@ rtr_create_rtr_info(
 	rtr_info->allocated = true;
 	rtr_info->cursor = cursor;
 	rtr_info->index = index;
+	rtr_info->thr = thr;
 
 	if (init_matches) {
 		rtr_info->heap = mem_heap_create(sizeof(*(rtr_info->matches)));
diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index a51e30e28ce..d7e495ff3d7 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -87,7 +87,6 @@ this program; if not, write to the Free Software Foundation, Inc.,
 #include "fts0plugin.h"
 #include "fts0priv.h"
 #include "fts0types.h"
-#include "ibuf0ibuf.h"
 #include "lock0lock.h"
 #include "log0crypt.h"
 #include "mtr0mtr.h"
@@ -399,25 +398,6 @@ static TYPELIB innodb_deadlock_report_typelib = {
 	NULL
 };
 
-/** Allowed values of innodb_change_buffering */
-static const char* innodb_change_buffering_names[] = {
-	"none",		/* IBUF_USE_NONE */
-	"inserts",	/* IBUF_USE_INSERT */
-	"deletes",	/* IBUF_USE_DELETE_MARK */
-	"changes",	/* IBUF_USE_INSERT_DELETE_MARK */
-	"purges",	/* IBUF_USE_DELETE */
-	"all",		/* IBUF_USE_ALL */
-	NullS
-};
-
-/** Enumeration of innodb_change_buffering */
-static TYPELIB innodb_change_buffering_typelib = {
-	array_elements(innodb_change_buffering_names) - 1,
-	"innodb_change_buffering_typelib",
-	innodb_change_buffering_names,
-	NULL
-};
-
 /** Allowed values of innodb_instant_alter_column_allowed */
 const char* innodb_instant_alter_column_allowed_names[] = {
 	"never", /* compatible with MariaDB 5.5 to 10.2 */
@@ -531,9 +511,6 @@ mysql_pfs_key_t	fts_cache_mutex_key;
 mysql_pfs_key_t	fts_cache_init_mutex_key;
 mysql_pfs_key_t	fts_delete_mutex_key;
 mysql_pfs_key_t	fts_doc_id_mutex_key;
-mysql_pfs_key_t	ibuf_bitmap_mutex_key;
-mysql_pfs_key_t	ibuf_mutex_key;
-mysql_pfs_key_t	ibuf_pessimistic_insert_mutex_key;
 mysql_pfs_key_t	recalc_pool_mutex_key;
 mysql_pfs_key_t	purge_sys_pq_mutex_key;
 mysql_pfs_key_t	recv_sys_mutex_key;
@@ -565,8 +542,6 @@ static PSI_mutex_info all_innodb_mutexes[] = {
 	PSI_KEY(fts_cache_init_mutex),
 	PSI_KEY(fts_delete_mutex),
 	PSI_KEY(fts_doc_id_mutex),
-	PSI_KEY(ibuf_mutex),
-	PSI_KEY(ibuf_pessimistic_insert_mutex),
 	PSI_KEY(index_online_log),
 	PSI_KEY(page_zip_stat_per_index_mutex),
 	PSI_KEY(purge_sys_pq_mutex),
@@ -973,20 +948,6 @@ static SHOW_VAR innodb_status_variables[]= {
   {"dblwr_writes", &export_vars.innodb_dblwr_writes, SHOW_SIZE_T},
   {"deadlocks", &lock_sys.deadlocks, SHOW_SIZE_T},
   {"history_list_length", &export_vars.innodb_history_list_length,SHOW_SIZE_T},
-  {"ibuf_discarded_delete_marks", &ibuf.n_discarded_ops[IBUF_OP_DELETE_MARK],
-   SHOW_SIZE_T},
-  {"ibuf_discarded_deletes", &ibuf.n_discarded_ops[IBUF_OP_DELETE],
-   SHOW_SIZE_T},
-  {"ibuf_discarded_inserts", &ibuf.n_discarded_ops[IBUF_OP_INSERT],
-   SHOW_SIZE_T},
-  {"ibuf_free_list", &ibuf.free_list_len, SHOW_SIZE_T},
-  {"ibuf_merged_delete_marks", &ibuf.n_merged_ops[IBUF_OP_DELETE_MARK],
-   SHOW_SIZE_T},
-  {"ibuf_merged_deletes", &ibuf.n_merged_ops[IBUF_OP_DELETE], SHOW_SIZE_T},
-  {"ibuf_merged_inserts", &ibuf.n_merged_ops[IBUF_OP_INSERT], SHOW_SIZE_T},
-  {"ibuf_merges", &ibuf.n_merges, SHOW_SIZE_T},
-  {"ibuf_segment_size", &ibuf.seg_size, SHOW_SIZE_T},
-  {"ibuf_size", &ibuf.size, SHOW_SIZE_T},
   {"log_waits", &log_sys.waits, SHOW_SIZE_T},
   {"log_write_requests", &log_sys.write_to_buf, SHOW_SIZE_T},
   {"log_writes", &log_sys.write_to_log, SHOW_SIZE_T},
@@ -3927,8 +3888,6 @@ static int innodb_init_params()
 		DBUG_RETURN(HA_ERR_INITIALIZATION);
 	}
 
-	DBUG_ASSERT(innodb_change_buffering <= IBUF_USE_ALL);
-
 	/* Check that interdependent parameters have sane values. */
 	if (srv_max_buf_pool_modified_pct < srv_max_dirty_pages_pct_lwm) {
 		sql_print_warning("InnoDB: innodb_max_dirty_pages_pct_lwm"
@@ -4005,11 +3964,6 @@ static int innodb_init_params()
 
 	fts_sort_pll_degree = num_pll_degree;
 
-	/* Store the default charset-collation number of this MySQL
-	installation */
-
-	data_mysql_default_charset_coll = (ulint) default_charset_info->number;
-
 	if (innodb_flush_method == 1 /* O_DSYNC */) {
 		log_sys.log_write_through = true;
 		fil_system.write_through = true;
@@ -4213,8 +4167,6 @@ static int innodb_init(void* p)
 	innobase_old_blocks_pct = buf_LRU_old_ratio_update(
 		innobase_old_blocks_pct, true);
 
-	ibuf_max_size_update(srv_change_buffer_max_size);
-
 	mysql_mutex_init(pending_checkpoint_mutex_key,
 			 &log_requests.mutex,
 			 MY_MUTEX_INIT_FAST);
@@ -4345,7 +4297,7 @@ innobase_start_trx_and_assign_read_view(
 	Do this only if transaction is using REPEATABLE READ isolation
 	level. */
 	trx->isolation_level = innobase_map_isolation_level(
-		thd_get_trx_isolation(thd));
+		thd_get_trx_isolation(thd)) & 3;
 
 	if (trx->isolation_level == TRX_ISO_REPEATABLE_READ) {
 		trx->read_view.open(trx);
@@ -6593,8 +6545,7 @@ uint8_t
 get_innobase_type_from_mysql_type(unsigned *unsigned_flag, const Field *field)
 {
 	/* The following asserts try to check that the MySQL type code fits in
-	8 bits: this is used in ibuf and also when DATA_NOT_NULL is ORed to
-	the type */
+	8 bits: this is used when DATA_NOT_NULL is ORed to the type */
 
 	static_assert(MYSQL_TYPE_STRING < 256, "compatibility");
 	static_assert(MYSQL_TYPE_VAR_STRING < 256, "compatibility");
@@ -15264,7 +15215,7 @@ ha_innobase::check(
 	}
 
 	/* Restore the original isolation level */
-	m_prebuilt->trx->isolation_level = old_isolation_level;
+	m_prebuilt->trx->isolation_level = old_isolation_level & 3;
 #ifdef BTR_CUR_HASH_ADAPT
 # if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
 	/* We validate the whole adaptive hash index for all tables
@@ -16297,7 +16248,7 @@ ha_innobase::store_lock(
 	if (lock_type != TL_IGNORE
 	    && trx->n_mysql_tables_in_use == 0) {
 		trx->isolation_level = innobase_map_isolation_level(
-			(enum_tx_isolation) thd_tx_isolation(thd));
+			(enum_tx_isolation) thd_tx_isolation(thd)) & 3;
 
 		if (trx->isolation_level <= TRX_ISO_READ_COMMITTED) {
 
@@ -17438,20 +17389,6 @@ innodb_old_blocks_pct_update(THD*, st_mysql_sys_var*, void*, const void* save)
 	innobase_old_blocks_pct = ratio;
 }
 
-/****************************************************************//**
-Update the system variable innodb_old_blocks_pct using the "saved"
-value. This function is registered as a callback with MySQL. */
-static
-void
-innodb_change_buffer_max_size_update(THD*, st_mysql_sys_var*, void*,
-				     const void* save)
-{
-	srv_change_buffer_max_size = *static_cast<const uint*>(save);
-	mysql_mutex_unlock(&LOCK_global_system_variables);
-	ibuf_max_size_update(srv_change_buffer_max_size);
-	mysql_mutex_lock(&LOCK_global_system_variables);
-}
-
 #ifdef UNIV_DEBUG
 static uint srv_fil_make_page_dirty_debug = 0;
 static uint srv_saved_page_number_debug;
@@ -19479,19 +19416,6 @@ static MYSQL_SYSVAR_BOOL(numa_interleave, srv_numa_interleave,
   NULL, NULL, FALSE);
 #endif /* HAVE_LIBNUMA */
 
-static MYSQL_SYSVAR_ENUM(change_buffering, innodb_change_buffering,
-  PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_DEPRECATED,
-  "Buffer changes to secondary indexes.",
-  nullptr, nullptr, IBUF_USE_NONE, &innodb_change_buffering_typelib);
-
-static MYSQL_SYSVAR_UINT(change_buffer_max_size,
-  srv_change_buffer_max_size,
-  PLUGIN_VAR_RQCMDARG,
-  "Maximum on-disk size of change buffer in terms of percentage"
-  " of the buffer pool.",
-  NULL, innodb_change_buffer_max_size_update,
-  CHANGE_BUFFER_DEFAULT_SIZE, 0, 50, 0);
-
 static MYSQL_SYSVAR_ENUM(stats_method, srv_innodb_stats_method,
    PLUGIN_VAR_RQCMDARG,
   "Specifies how InnoDB index statistics collection code should"
@@ -19499,18 +19423,6 @@ static MYSQL_SYSVAR_ENUM(stats_method, srv_innodb_stats_method,
   " NULLS_UNEQUAL and NULLS_IGNORED",
    NULL, NULL, SRV_STATS_NULLS_EQUAL, &innodb_stats_method_typelib);
 
-#if defined UNIV_DEBUG || defined UNIV_IBUF_DEBUG
-static MYSQL_SYSVAR_BOOL(change_buffer_dump, ibuf_dump,
-  PLUGIN_VAR_NOCMDARG | PLUGIN_VAR_READONLY,
-  "Dump the change buffer at startup.",
-  NULL, NULL, FALSE);
-
-static MYSQL_SYSVAR_UINT(change_buffering_debug, ibuf_debug,
-  PLUGIN_VAR_RQCMDARG,
-  "Debug flags for InnoDB change buffering (0=none, 1=try to buffer)",
-  NULL, NULL, 0, 0, 1, 0);
-#endif /* UNIV_DEBUG || UNIV_IBUF_DEBUG */
-
 static MYSQL_SYSVAR_ULONG(buf_dump_status_frequency, srv_buf_dump_status_frequency,
   PLUGIN_VAR_RQCMDARG,
   "A number between [0, 100] that tells how oftern buffer pool dump status "
@@ -19840,12 +19752,6 @@ static struct st_mysql_sys_var* innobase_system_variables[]= {
 #ifdef HAVE_LIBNUMA
   MYSQL_SYSVAR(numa_interleave),
 #endif /* HAVE_LIBNUMA */
-  MYSQL_SYSVAR(change_buffering),
-  MYSQL_SYSVAR(change_buffer_max_size),
-#if defined UNIV_DEBUG || defined UNIV_IBUF_DEBUG
-  MYSQL_SYSVAR(change_buffer_dump),
-  MYSQL_SYSVAR(change_buffering_debug),
-#endif /* UNIV_DEBUG || UNIV_IBUF_DEBUG */
   MYSQL_SYSVAR(random_read_ahead),
   MYSQL_SYSVAR(read_ahead_threshold),
   MYSQL_SYSVAR(read_only),
diff --git a/storage/innobase/handler/handler0alter.cc b/storage/innobase/handler/handler0alter.cc
index 91c1ff53d2d..abca00323e0 100644
--- a/storage/innobase/handler/handler0alter.cc
+++ b/storage/innobase/handler/handler0alter.cc
@@ -2154,8 +2154,7 @@ next_page:
     }
 
     next_page= false;
-    block= btr_block_get(*clust_index, next_page_no, BTR_SEARCH_LEAF, false,
-                         &mtr);
+    block= btr_block_get(*clust_index, next_page_no, BTR_SEARCH_LEAF, &mtr);
     if (!block)
       goto non_empty;
     page_cur_set_before_first(block, cur);
diff --git a/storage/innobase/handler/i_s.cc b/storage/innobase/handler/i_s.cc
index 9510a4a8bfc..2a26f4f5ac2 100644
--- a/storage/innobase/handler/i_s.cc
+++ b/storage/innobase/handler/i_s.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2007, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2014, 2022, MariaDB Corporation.
+Copyright (c) 2014, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -39,7 +39,6 @@ Created July 18, 2007 Vasil Dimov
 #include "dict0load.h"
 #include "buf0buddy.h"
 #include "buf0buf.h"
-#include "ibuf0ibuf.h"
 #include "dict0mem.h"
 #include "dict0types.h"
 #include "srv0start.h"
@@ -80,10 +79,7 @@ in i_s_page_type[] array */
 /** R-tree index page */
 #define	I_S_PAGE_TYPE_RTREE		(FIL_PAGE_TYPE_LAST + 1)
 
-/** Change buffer B-tree page */
-#define	I_S_PAGE_TYPE_IBUF		(FIL_PAGE_TYPE_LAST + 2)
-
-#define I_S_PAGE_TYPE_LAST		I_S_PAGE_TYPE_IBUF
+#define I_S_PAGE_TYPE_LAST		I_S_PAGE_TYPE_RTREE
 
 #define I_S_PAGE_TYPE_BITS		4
 
@@ -104,9 +100,6 @@ static buf_page_desc_t	i_s_page_type[] = {
 	{"COMPRESSED_BLOB2", FIL_PAGE_TYPE_ZBLOB2},
 	{"UNKNOWN", I_S_PAGE_TYPE_UNKNOWN},
 	{"RTREE_INDEX", I_S_PAGE_TYPE_RTREE},
-	{"IBUF_INDEX", I_S_PAGE_TYPE_IBUF},
-	{"PAGE COMPRESSED", FIL_PAGE_PAGE_COMPRESSED},
-	{"PAGE COMPRESSED AND ENCRYPTED", FIL_PAGE_PAGE_COMPRESSED_ENCRYPTED},
 };
 
 /** This structure defines information we will fetch from pages
@@ -3776,17 +3769,17 @@ i_s_innodb_buffer_page_fill(
 		OK(fields[IDX_BUFFER_PAGE_STATE]->store(
 			   std::min<uint32_t>(3, page_info->state) + 1, true));
 
-		static_assert(buf_page_t::UNFIXED == 1U << 29, "comp.");
+		static_assert(buf_page_t::UNFIXED == 2U << 29, "comp.");
 		static_assert(buf_page_t::READ_FIX == 4U << 29, "comp.");
-		static_assert(buf_page_t::WRITE_FIX == 5U << 29, "comp.");
+		static_assert(buf_page_t::WRITE_FIX == 6U << 29, "comp.");
 
 		unsigned io_fix = page_info->state >> 29;
 		if (io_fix < 4) {
 			io_fix = 1;
-		} else if (io_fix > 5) {
-			io_fix = 3;
+		} else if (io_fix == 4) {
+			io_fix = 2;
 		} else {
-			io_fix -= 2;
+			io_fix = 3;
 		}
 
 		OK(fields[IDX_BUFFER_PAGE_IO_FIX]->store(io_fix, true));
@@ -3824,14 +3817,9 @@ i_s_innodb_set_page_type(
 		their values are defined as 17855 and 17854, so we cannot
 		use them to index into i_s_page_type[] array, its array index
 		in the i_s_page_type[] array is I_S_PAGE_TYPE_INDEX
-		(1) for index pages or I_S_PAGE_TYPE_IBUF for
-		change buffer index pages */
+		(1) for index pages */
 		if (page_type == FIL_PAGE_RTREE) {
 			page_info->page_type = I_S_PAGE_TYPE_RTREE;
-		} else if (page_info->index_id
-			   == static_cast<index_id_t>(DICT_IBUF_ID_MIN
-						      + IBUF_SPACE_ID)) {
-			page_info->page_type = I_S_PAGE_TYPE_IBUF;
 		} else {
 			ut_ad(page_type == FIL_PAGE_INDEX
 			      || page_type == FIL_PAGE_TYPE_INSTANT);
@@ -3876,9 +3864,9 @@ i_s_innodb_buffer_page_get_info(
 	static_assert(buf_page_t::NOT_USED == 0, "compatibility");
 	static_assert(buf_page_t::MEMORY == 1, "compatibility");
 	static_assert(buf_page_t::REMOVE_HASH == 2, "compatibility");
-	static_assert(buf_page_t::UNFIXED == 1U << 29, "compatibility");
+	static_assert(buf_page_t::UNFIXED == 2U << 29, "compatibility");
 	static_assert(buf_page_t::READ_FIX == 4U << 29, "compatibility");
-	static_assert(buf_page_t::WRITE_FIX == 5U << 29, "compatibility");
+	static_assert(buf_page_t::WRITE_FIX == 6U << 29, "compatibility");
 
 	page_info->state = bpage->state();
 
@@ -4268,17 +4256,17 @@ i_s_innodb_buf_page_lru_fill(
 		OK(fields[IDX_BUF_LRU_PAGE_STATE]->store(
 			   page_info->compressed_only, true));
 
-		static_assert(buf_page_t::UNFIXED == 1U << 29, "comp.");
+		static_assert(buf_page_t::UNFIXED == 2U << 29, "comp.");
 		static_assert(buf_page_t::READ_FIX == 4U << 29, "comp.");
-		static_assert(buf_page_t::WRITE_FIX == 5U << 29, "comp.");
+		static_assert(buf_page_t::WRITE_FIX == 6U << 29, "comp.");
 
 		unsigned io_fix = page_info->state >> 29;
 		if (io_fix < 4) {
 			io_fix = 1;
-		} else if (io_fix > 5) {
-			io_fix = 3;
+		} else if (io_fix == 4) {
+			io_fix = 2;
 		} else {
-			io_fix -= 2;
+			io_fix = 3;
 		}
 
 		OK(fields[IDX_BUF_LRU_PAGE_IO_FIX]->store(io_fix, true));
diff --git a/storage/innobase/ibuf/ibuf0ibuf.cc b/storage/innobase/ibuf/ibuf0ibuf.cc
index 2512232c7ca..dcee5a7b0ef 100644
--- a/storage/innobase/ibuf/ibuf0ibuf.cc
+++ b/storage/innobase/ibuf/ibuf0ibuf.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1997, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2016, 2022, MariaDB Corporation.
+Copyright (c) 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -17,1249 +17,98 @@ this program; if not, write to the Free Software Foundation, Inc.,
 
 *****************************************************************************/
 
-/**************************************************//**
+/**
 @file ibuf/ibuf0ibuf.cc
-Insert buffer
-
-Created 7/19/1997 Heikki Tuuri
-*******************************************************/
+Upgrade and removal of the InnoDB change buffer
+*/
 
 #include "ibuf0ibuf.h"
 #include "btr0sea.h"
-
-/** Number of bits describing a single page */
-#define IBUF_BITS_PER_PAGE	4
-/** The start address for an insert buffer bitmap page bitmap */
-#define IBUF_BITMAP		PAGE_DATA
-
-#include "buf0buf.h"
-#include "buf0rea.h"
-#include "fsp0fsp.h"
-#include "trx0sys.h"
-#include "fil0fil.h"
-#include "rem0rec.h"
-#include "btr0cur.h"
 #include "btr0pcur.h"
-#include "btr0btr.h"
 #include "row0upd.h"
-#include "dict0boot.h"
-#include "fut0lst.h"
-#include "lock0lock.h"
-#include "log0recv.h"
-#include "que0que.h"
-#include "srv0start.h" /* srv_shutdown_state */
-#include "rem0cmp.h"
+#include "my_service_manager.h"
 #include "log.h"
 
-/*	STRUCTURE OF AN INSERT BUFFER RECORD
+/** Possible operations buffered in the change buffer. */
+enum ibuf_op
+{
+  IBUF_OP_INSERT= 0,
+  IBUF_OP_DELETE_MARK= 1,
+  IBUF_OP_DELETE= 2,
+};
+
+constexpr const page_id_t ibuf_root{0, FSP_IBUF_TREE_ROOT_PAGE_NO};
+constexpr const page_id_t ibuf_header{0, FSP_IBUF_HEADER_PAGE_NO};
+constexpr const index_id_t ibuf_index_id{0xFFFFFFFF00000000ULL};
 
-In versions < 4.1.x:
+/* Format of the change buffer records:
+
+MySQL 3.23 and MySQL 4.0 (not supported since MySQL 5.6.5 and MariaDB 10.0.11):
 
 1. The first field is the page number.
 2. The second field is an array which stores type info for each subsequent
-   field. We store the information which affects the ordering of records, and
+   field (4 bytes per column).
+   We store the information which affects the ordering of records, and
    also the physical storage size of an SQL NULL value. E.g., for CHAR(10) it
    is 10 bytes.
 3. Next we have the fields of the actual index record.
 
-In versions >= 4.1.x:
-
-Note that contary to what we planned in the 1990's, there will only be one
-insert buffer tree, and that is in the system tablespace of InnoDB.
+MySQL 4.1:
 
 1. The first field is the space id.
 2. The second field is a one-byte marker (0) which differentiates records from
    the < 4.1.x storage format.
 3. The third field is the page number.
-4. The fourth field contains the type info, where we have also added 2 bytes to
-   store the charset. In the compressed table format of 5.0.x we must add more
-   information here so that we can build a dummy 'index' struct which 5.0.x
-   can use in the binary search on the index page in the ibuf merge phase.
+4. The fourth field contains the type info
+   (6 bytes per index field, 16-bit collation information added).
+   Unless ROW_FORMAT=REDUNDANT, we add more metadata here so that
+   we can access records in the index page.
 5. The rest of the fields contain the fields of the actual index record.
 
-In versions >= 5.0.3:
+MySQL 5.0 (starting with MySQL 5.0.3) and MySQL 5.1:
 
 The first byte of the fourth field is an additional marker (0) if the record
-is in the compact format.  The presence of this marker can be detected by
-looking at the length of the field modulo DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE.
+is not in ROW_FORMAT=REDUNDANT. The presence of this marker can be detected by
+looking at the length of the field modulo 6.
 
 The high-order bit of the character set field in the type info is the
 "nullable" flag for the field.
 
-In versions >= 5.5:
+MySQL 5.5 and MariaDB 5.5 and later:
 
-The optional marker byte at the start of the fourth field is replaced by
-mandatory 3 fields, totaling 4 bytes:
+Unless innodb_change_buffering=inserts, the optional marker byte at
+the start of the fourth field may be replaced by mandatory 3 fields,
+comprising 4 bytes:
 
  1. 2 bytes: Counter field, used to sort records within a (space id, page
     no) in the order they were added. This is needed so that for example the
     sequence of operations "INSERT x, DEL MARK x, INSERT x" is handled
     correctly.
 
- 2. 1 byte: Operation type (see ibuf_op_t).
+ 2. 1 byte: Operation type (see ibuf_op).
 
- 3. 1 byte: Flags. Currently only one flag exists, IBUF_REC_COMPACT.
-
-To ensure older records, which do not have counters to enforce correct
-sorting, are merged before any new records, ibuf_insert checks if we're
-trying to insert to a position that contains old-style records, and if so,
-refuses the insert. Thus, ibuf pages are gradually converted to the new
-format as their corresponding buffer pool pages are read into memory.
+ 3. 1 byte: 0=ROW_FORMAT=REDUNDANT, 1=other
 */
 
-
-/*	PREVENTING DEADLOCKS IN THE INSERT BUFFER SYSTEM
-
-If an OS thread performs any operation that brings in disk pages from
-non-system tablespaces into the buffer pool, or creates such a page there,
-then the operation may have as a side effect an insert buffer index tree
-compression. Thus, the tree latch of the insert buffer tree may be acquired
-in the x-mode, and also the file space latch of the system tablespace may
-be acquired in the x-mode.
-
-Also, an insert to an index in a non-system tablespace can have the same
-effect. How do we know this cannot lead to a deadlock of OS threads? There
-is a problem with the i\o-handler threads: they break the latching order
-because they own x-latches to pages which are on a lower level than the
-insert buffer tree latch, its page latches, and the tablespace latch an
-insert buffer operation can reserve.
-
-The solution is the following: Let all the tree and page latches connected
-with the insert buffer be later in the latching order than the fsp latch and
-fsp page latches.
-
-Insert buffer pages must be such that the insert buffer is never invoked
-when these pages are accessed as this would result in a recursion violating
-the latching order. We let a special i/o-handler thread take care of i/o to
-the insert buffer pages and the ibuf bitmap pages, as well as the fsp bitmap
-pages and the first inode page, which contains the inode of the ibuf tree: let
-us call all these ibuf pages. To prevent deadlocks, we do not let a read-ahead
-access both non-ibuf and ibuf pages.
-
-Then an i/o-handler for the insert buffer never needs to access recursively the
-insert buffer tree and thus obeys the latching order. On the other hand, other
-i/o-handlers for other tablespaces may require access to the insert buffer,
-but because all kinds of latches they need to access there are later in the
-latching order, no violation of the latching order occurs in this case,
-either.
-
-A problem is how to grow and contract an insert buffer tree. As it is later
-in the latching order than the fsp management, we have to reserve the fsp
-latch first, before adding or removing pages from the insert buffer tree.
-We let the insert buffer tree have its own file space management: a free
-list of pages linked to the tree root. To prevent recursive using of the
-insert buffer when adding pages to the tree, we must first load these pages
-to memory, obtaining a latch on them, and only after that add them to the
-free list of the insert buffer tree. More difficult is removing of pages
-from the free list. If there is an excess of pages in the free list of the
-ibuf tree, they might be needed if some thread reserves the fsp latch,
-intending to allocate more file space. So we do the following: if a thread
-reserves the fsp latch, we check the writer count field of the latch. If
-this field has value 1, it means that the thread did not own the latch
-before entering the fsp system, and the mtr of the thread contains no
-modifications to the fsp pages. Now we are free to reserve the ibuf latch,
-and check if there is an excess of pages in the free list. We can then, in a
-separate mini-transaction, take them out of the free list and free them to
-the fsp system.
-
-To avoid deadlocks in the ibuf system, we divide file pages into three levels:
-
-(1) non-ibuf pages,
-(2) ibuf tree pages and the pages in the ibuf tree free list, and
-(3) ibuf bitmap pages.
-
-No OS thread is allowed to access higher level pages if it has latches to
-lower level pages; even if the thread owns a B-tree latch it must not access
-the B-tree non-leaf pages if it has latches on lower level pages. Read-ahead
-is only allowed for level 1 and 2 pages. Dedicated i/o-handler threads handle
-exclusively level 1 i/o. A dedicated i/o handler thread handles exclusively
-level 2 i/o. However, if an OS thread does the i/o handling for itself, i.e.,
-it uses synchronous aio, it can access any pages, as long as it obeys the
-access order rules. */
-
-/** Operations that can currently be buffered. */
-ulong	innodb_change_buffering;
-
-#if defined UNIV_DEBUG || defined UNIV_IBUF_DEBUG
-/** Dump the change buffer at startup */
-my_bool	ibuf_dump;
-/** Flag to control insert buffer debugging. */
-uint	ibuf_debug;
-#endif /* UNIV_DEBUG || UNIV_IBUF_DEBUG */
-
-/** The insert buffer control structure */
-ibuf_t	ibuf;
-
-/** @name Offsets to the per-page bits in the insert buffer bitmap */
-/* @{ */
-#define	IBUF_BITMAP_FREE	0	/*!< Bits indicating the
-					amount of free space */
-#define IBUF_BITMAP_BUFFERED	2	/*!< TRUE if there are buffered
-					changes for the page */
-#define IBUF_BITMAP_IBUF	3	/*!< TRUE if page is a part of
-					the ibuf tree, excluding the
-					root page, or is in the free
-					list of the ibuf */
-/* @} */
-
-#define IBUF_REC_FIELD_SPACE	0	/*!< in the pre-4.1 format,
-					the page number. later, the space_id */
-#define IBUF_REC_FIELD_MARKER	1	/*!< starting with 4.1, a marker
-					consisting of 1 byte that is 0 */
-#define IBUF_REC_FIELD_PAGE	2	/*!< starting with 4.1, the
-					page number */
-#define IBUF_REC_FIELD_METADATA	3	/* the metadata field */
-#define IBUF_REC_FIELD_USER	4	/* first user field */
-
-/* Various constants for checking the type of an ibuf record and extracting
-data from it. For details, see the description of the record format at the
-top of this file. */
-
-/** @name Format of the IBUF_REC_FIELD_METADATA of an insert buffer record
-The fourth column in the MySQL 5.5 format contains an operation
-type, counter, and some flags. */
-/* @{ */
-#define IBUF_REC_INFO_SIZE	4	/*!< Combined size of info fields at
-					the beginning of the fourth field */
-
-/* Offsets for the fields at the beginning of the fourth field */
-#define IBUF_REC_OFFSET_COUNTER	0	/*!< Operation counter */
-#define IBUF_REC_OFFSET_TYPE	2	/*!< Type of operation */
-#define IBUF_REC_OFFSET_FLAGS	3	/*!< Additional flags */
-
-/* Record flag masks */
-#define IBUF_REC_COMPACT	0x1	/*!< Set in
-					IBUF_REC_OFFSET_FLAGS if the
-					user index is in COMPACT
-					format or later */
-
-
-#ifndef SAFE_MUTEX
-static
-#endif /* SAFE_MUTEX */
-/** The mutex protecting the insert buffer */
-mysql_mutex_t ibuf_mutex,
-	/** The mutex covering pessimistic inserts into the change buffer */
-	ibuf_pessimistic_insert_mutex;
-
-/** The area in pages from which contract looks for page numbers for merge */
-const ulint		IBUF_MERGE_AREA = 8;
-
-/** Inside the merge area, pages which have at most 1 per this number less
-buffered entries compared to maximum volume that can buffered for a single
-page are merged along with the page whose buffer became full */
-const ulint		IBUF_MERGE_THRESHOLD = 4;
-
-/** In ibuf_contract at most this number of pages is read to memory in one
-batch, in order to merge the entries for them in the insert buffer */
-const ulint		IBUF_MAX_N_PAGES_MERGED = IBUF_MERGE_AREA;
-
-/** If the combined size of the ibuf trees exceeds ibuf.max_size by
-this many pages, we start to contract it synchronous contract, but do
-not insert */
-const ulint		IBUF_CONTRACT_DO_NOT_INSERT = 10;
-
-/* TODO: how to cope with drop table if there are records in the insert
-buffer for the indexes of the table? Is there actually any problem,
-because ibuf merge is done to a page when it is read in, and it is
-still physically like the index page even if the index would have been
-dropped! So, there seems to be no problem. */
-
-/******************************************************************//**
-Sets the flag in the current mini-transaction record indicating we're
-inside an insert buffer routine. */
-UNIV_INLINE
-void
-ibuf_enter(
-/*=======*/
-	mtr_t*	mtr)	/*!< in/out: mini-transaction */
-{
-	ut_ad(!mtr->is_inside_ibuf());
-	mtr->enter_ibuf();
-}
-
-/******************************************************************//**
-Sets the flag in the current mini-transaction record indicating we're
-exiting an insert buffer routine. */
-UNIV_INLINE
-void
-ibuf_exit(
-/*======*/
-	mtr_t*	mtr)	/*!< in/out: mini-transaction */
-{
-	ut_ad(mtr->is_inside_ibuf());
-	mtr->exit_ibuf();
-}
-
-/**************************************************************//**
-Commits an insert buffer mini-transaction and sets the persistent
-cursor latch mode to BTR_NO_LATCHES, that is, detaches the cursor. */
-UNIV_INLINE
-void
-ibuf_btr_pcur_commit_specify_mtr(
-/*=============================*/
-	btr_pcur_t*	pcur,	/*!< in/out: persistent cursor */
-	mtr_t*		mtr)	/*!< in/out: mini-transaction */
-{
-	ut_d(ibuf_exit(mtr));
-	btr_pcur_commit_specify_mtr(pcur, mtr);
-}
-
-/******************************************************************//**
-Gets the ibuf header page and x-latches it.
-@return insert buffer header page */
-static
-page_t*
-ibuf_header_page_get(
-/*=================*/
-	mtr_t*	mtr)	/*!< in/out: mini-transaction */
-{
-	ut_ad(!ibuf_inside(mtr));
-
-	buf_block_t* block = buf_page_get(
-		page_id_t(IBUF_SPACE_ID, FSP_IBUF_HEADER_PAGE_NO),
-		0, RW_X_LATCH, mtr);
-
-	return block ? block->page.frame : nullptr;
-}
-
-/** Acquire the change buffer root page.
-@param[in,out]  mtr     mini-transaction
-@return change buffer root page, SX-latched */
-static buf_block_t *ibuf_tree_root_get(mtr_t *mtr, dberr_t *err= nullptr)
-{
-  ut_ad(ibuf_inside(mtr));
-  mysql_mutex_assert_owner(&ibuf_mutex);
-
-  mtr_sx_lock_index(ibuf.index, mtr);
-
-  buf_block_t *block=
-    buf_page_get_gen(page_id_t{IBUF_SPACE_ID, FSP_IBUF_TREE_ROOT_PAGE_NO},
-                     0, RW_SX_LATCH, nullptr, BUF_GET, mtr, err);
-  ut_ad(!block || ibuf.empty == page_is_empty(block->page.frame));
-  return block;
-}
-
-/******************************************************************//**
-Closes insert buffer and frees the data structures. */
-void
-ibuf_close(void)
-/*============*/
-{
-	if (!ibuf.index) {
-		return;
-	}
-
-	mysql_mutex_destroy(&ibuf_pessimistic_insert_mutex);
-	mysql_mutex_destroy(&ibuf_mutex);
-
-	dict_table_t*	ibuf_table = ibuf.index->table;
-	ibuf.index->lock.free();
-	dict_mem_index_free(ibuf.index);
-	dict_mem_table_free(ibuf_table);
-	ibuf.index = NULL;
-}
-
-/******************************************************************//**
-Updates the size information of the ibuf, assuming the segment size has not
-changed. */
-static
-void
-ibuf_size_update(
-/*=============*/
-	const page_t*	root)	/*!< in: ibuf tree root */
-{
-	mysql_mutex_assert_owner(&ibuf_mutex);
-
-	ibuf.free_list_len = flst_get_len(root + PAGE_HEADER
-					   + PAGE_BTR_IBUF_FREE_LIST);
-
-	ibuf.height = 1 + btr_page_get_level(root);
-
-	/* the '1 +' is the ibuf header page */
-	ibuf.size = ibuf.seg_size - (1 + ibuf.free_list_len);
-}
-
-/******************************************************************//**
-Creates the insert buffer data structure at a database startup and initializes
-the data structures for the insert buffer.
-@return DB_SUCCESS or failure */
-dberr_t
-ibuf_init_at_db_start(void)
-/*=======================*/
-{
-	page_t*		root;
-
-	ut_ad(!ibuf.index);
-	mtr_t mtr;
-	mtr.start();
-	compile_time_assert(IBUF_SPACE_ID == TRX_SYS_SPACE);
-	compile_time_assert(IBUF_SPACE_ID == 0);
-	mtr.x_lock_space(fil_system.sys_space);
-	dberr_t err;
-	buf_block_t* header_page = buf_page_get_gen(
-		page_id_t(IBUF_SPACE_ID, FSP_IBUF_HEADER_PAGE_NO),
-		0, RW_X_LATCH, nullptr, BUF_GET, &mtr, &err);
-
-	if (!header_page) {
-err_exit:
-		sql_print_error("InnoDB: The change buffer is corrupted");
-		mtr.commit();
-		return err;
-	}
-
-	fseg_n_reserved_pages(*header_page,
-			      IBUF_HEADER + IBUF_TREE_SEG_HEADER
-			      + header_page->page.frame, &ibuf.seg_size, &mtr);
-
-	do {
-		DBUG_EXECUTE_IF("intermittent_read_failure", continue;);
-		ut_ad(ibuf.seg_size >= 2);
-	} while (0);
-
-	if (buf_block_t* block =
-	    buf_page_get_gen(page_id_t(IBUF_SPACE_ID,
-				       FSP_IBUF_TREE_ROOT_PAGE_NO),
-			     0, RW_X_LATCH, nullptr, BUF_GET, &mtr, &err)) {
-		root = buf_block_get_frame(block);
-	} else {
-		goto err_exit;
-	}
-
-	if (page_is_comp(root) || fil_page_get_type(root) != FIL_PAGE_INDEX
-	    || btr_page_get_index_id(root) != DICT_IBUF_ID_MIN) {
-		err = DB_CORRUPTION;
-		goto err_exit;
-	}
-
-	/* At startup we intialize ibuf to have a maximum of
-	CHANGE_BUFFER_DEFAULT_SIZE in terms of percentage of the
-	buffer pool size. Once ibuf struct is initialized this
-	value is updated with the user supplied size by calling
-	ibuf_max_size_update(). */
-	ibuf.max_size = ((buf_pool_get_curr_size() >> srv_page_size_shift)
-			  * CHANGE_BUFFER_DEFAULT_SIZE) / 100;
-
-	mysql_mutex_init(ibuf_mutex_key, &ibuf_mutex, nullptr);
-	mysql_mutex_init(ibuf_pessimistic_insert_mutex_key,
-			 &ibuf_pessimistic_insert_mutex, nullptr);
-
-	mysql_mutex_lock(&ibuf_mutex);
-	ibuf_size_update(root);
-	mysql_mutex_unlock(&ibuf_mutex);
-
-	ibuf.empty = page_is_empty(root);
-	mtr.commit();
-
-	ibuf.index = dict_mem_index_create(
-		dict_table_t::create(
-			{C_STRING_WITH_LEN("innodb_change_buffer")},
-			fil_system.sys_space, 1, 0, 0, 0),
-		"CLUST_IND",
-		DICT_CLUSTERED | DICT_IBUF, 1);
-	ibuf.index->id = DICT_IBUF_ID_MIN + IBUF_SPACE_ID;
-	ibuf.index->n_uniq = REC_MAX_N_FIELDS;
-	ibuf.index->lock.SRW_LOCK_INIT(index_tree_rw_lock_key);
-#ifdef BTR_CUR_ADAPT
-	ibuf.index->search_info = btr_search_info_create(ibuf.index->heap);
-#endif /* BTR_CUR_ADAPT */
-	ibuf.index->page = FSP_IBUF_TREE_ROOT_PAGE_NO;
-	ut_d(ibuf.index->cached = TRUE);
-
-#if defined UNIV_DEBUG || defined UNIV_IBUF_DEBUG
-	if (!ibuf_dump) {
-		return DB_SUCCESS;
-	}
-	ib::info() << "Dumping the change buffer";
-	ibuf_mtr_start(&mtr);
-	btr_pcur_t pcur;
-	if (DB_SUCCESS
-	    == pcur.open_leaf(true, ibuf.index, BTR_SEARCH_LEAF, &mtr)) {
-		while (btr_pcur_move_to_next_user_rec(&pcur, &mtr)) {
-			rec_print_old(stderr, btr_pcur_get_rec(&pcur));
-		}
-	}
-	ibuf_mtr_commit(&mtr);
-	ib::info() << "Dumped the change buffer";
-#endif
-
-	return DB_SUCCESS;
-}
-
-/*********************************************************************//**
-Updates the max_size value for ibuf. */
-void
-ibuf_max_size_update(
-/*=================*/
-	ulint	new_val)	/*!< in: new value in terms of
-				percentage of the buffer pool size */
-{
-	if (UNIV_UNLIKELY(!ibuf.index)) return;
-	ulint	new_size = ((buf_pool_get_curr_size() >> srv_page_size_shift)
-			    * new_val) / 100;
-	mysql_mutex_lock(&ibuf_mutex);
-	ibuf.max_size = new_size;
-	mysql_mutex_unlock(&ibuf_mutex);
-}
-
-# ifdef UNIV_DEBUG
-/** Gets the desired bits for a given page from a bitmap page.
-@param[in]	page		bitmap page
-@param[in]	page_id		page id whose bits to get
-@param[in]	zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@param[in]	bit		IBUF_BITMAP_FREE, IBUF_BITMAP_BUFFERED, ...
-@param[in,out]	mtr		mini-transaction holding an x-latch on the
-bitmap page
-@return value of bits */
-#  define ibuf_bitmap_page_get_bits(page, page_id, zip_size, bit, mtr)	\
-	ibuf_bitmap_page_get_bits_low(page, page_id, zip_size,		\
-				      MTR_MEMO_PAGE_X_FIX, mtr, bit)
-# else /* UNIV_DEBUG */
-/** Gets the desired bits for a given page from a bitmap page.
-@param[in]	page		bitmap page
-@param[in]	page_id		page id whose bits to get
-@param[in]	zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@param[in]	bit		IBUF_BITMAP_FREE, IBUF_BITMAP_BUFFERED, ...
-@param[in,out]	mtr		mini-transaction holding an x-latch on the
-bitmap page
-@return value of bits */
-#  define ibuf_bitmap_page_get_bits(page, page_id, zip_size, bit, mtr)	\
-	ibuf_bitmap_page_get_bits_low(page, page_id, zip_size, bit)
-# endif /* UNIV_DEBUG */
-
-/** Gets the desired bits for a given page from a bitmap page.
-@param[in]	page		bitmap page
-@param[in]	page_id		page id whose bits to get
-@param[in]	zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@param[in]	latch_type	MTR_MEMO_PAGE_X_FIX, MTR_MEMO_BUF_FIX, ...
-@param[in,out]	mtr		mini-transaction holding latch_type on the
-bitmap page
-@param[in]	bit		IBUF_BITMAP_FREE, IBUF_BITMAP_BUFFERED, ...
-@return value of bits */
-UNIV_INLINE
-ulint
-ibuf_bitmap_page_get_bits_low(
-	const page_t*		page,
-	const page_id_t		page_id,
-	ulint			zip_size,
-#ifdef UNIV_DEBUG
-	ulint			latch_type,
-	mtr_t*			mtr,
-#endif /* UNIV_DEBUG */
-	ulint			bit)
-{
-	ulint	byte_offset;
-	ulint	bit_offset;
-	ulint	map_byte;
-	ulint	value;
-	const ulint size = zip_size ? zip_size : srv_page_size;
-
-	ut_ad(ut_is_2pow(zip_size));
-	ut_ad(bit < IBUF_BITS_PER_PAGE);
-	compile_time_assert(!(IBUF_BITS_PER_PAGE % 2));
-	ut_ad(mtr->memo_contains_page_flagged(page, latch_type));
-
-	bit_offset = (page_id.page_no() & (size - 1))
-		* IBUF_BITS_PER_PAGE + bit;
-
-	byte_offset = bit_offset / 8;
-	bit_offset = bit_offset % 8;
-
-	ut_ad(byte_offset + IBUF_BITMAP < srv_page_size);
-
-	map_byte = mach_read_from_1(page + IBUF_BITMAP + byte_offset);
-
-	value = ut_bit_get_nth(map_byte, bit_offset);
-
-	if (bit == IBUF_BITMAP_FREE) {
-		ut_ad(bit_offset + 1 < 8);
-
-		value = value * 2 + ut_bit_get_nth(map_byte, bit_offset + 1);
-	}
-
-	return(value);
-}
-
-/** Sets the desired bit for a given page in a bitmap page.
-@tparam bit	IBUF_BITMAP_FREE, IBUF_BITMAP_BUFFERED, ...
-@param[in,out]	block		bitmap page
-@param[in]	page_id		page id whose bits to set
-@param[in]	physical_size	page size
-@param[in]	val		value to set
-@param[in,out]	mtr		mtr containing an x-latch to the bitmap page */
-template<ulint bit>
-static void
-ibuf_bitmap_page_set_bits(
-	buf_block_t*		block,
-	const page_id_t		page_id,
-	ulint			physical_size,
-	ulint			val,
-	mtr_t*			mtr)
-{
-	ulint	byte_offset;
-	ulint	bit_offset;
-
-	static_assert(bit < IBUF_BITS_PER_PAGE, "wrong bit");
-	compile_time_assert(!(IBUF_BITS_PER_PAGE % 2));
-	ut_ad(mtr->memo_contains_flagged(block, MTR_MEMO_PAGE_X_FIX));
-	ut_ad(mtr->is_named_space(page_id.space()));
-
-	bit_offset = (page_id.page_no() % physical_size)
-		* IBUF_BITS_PER_PAGE + bit;
-
-	byte_offset = bit_offset / 8;
-	bit_offset = bit_offset % 8;
-
-	ut_ad(byte_offset + IBUF_BITMAP < srv_page_size);
-
-	byte* map_byte = &block->page.frame[IBUF_BITMAP + byte_offset];
-	byte b = *map_byte;
-
-	if (bit == IBUF_BITMAP_FREE) {
-		ut_ad(bit_offset + 1 < 8);
-		ut_ad(val <= 3);
-		b &= static_cast<byte>(~(3U << bit_offset));
-		b |= static_cast<byte>(((val & 2) >> 1) << bit_offset
-				       | (val & 1) << (bit_offset + 1));
-	} else {
-		ut_ad(val <= 1);
-		b &= static_cast<byte>(~(1U << bit_offset));
-#if defined __GNUC__ && !defined __clang__ && __GNUC__ < 6
-# pragma GCC diagnostic push
-# pragma GCC diagnostic ignored "-Wconversion" /* GCC 5 may need this here */
-#endif
-		b |= static_cast<byte>(val << bit_offset);
-#if defined __GNUC__ && !defined __clang__ && __GNUC__ < 6
-# pragma GCC diagnostic pop
-#endif
-	}
-
-	mtr->write<1,mtr_t::MAYBE_NOP>(*block, map_byte, b);
-}
-
-/** Calculates the bitmap page number for a given page number.
-@param[in]	page_id		page id
-@param[in]	size		page size
-@return the bitmap page id where the file page is mapped */
-inline page_id_t ibuf_bitmap_page_no_calc(const page_id_t page_id, ulint size)
-{
-  if (!size)
-    size= srv_page_size;
-
-  return page_id_t(page_id.space(), FSP_IBUF_BITMAP_OFFSET
-		   + uint32_t(page_id.page_no() & ~(size - 1)));
-}
-
-/** Gets the ibuf bitmap page where the bits describing a given file page are
-stored.
-@param[in]	page_id		page id of the file page
-@param[in]	zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@param[in,out]	mtr		mini-transaction
-@return bitmap page where the file page is mapped, that is, the bitmap
-page containing the descriptor bits for the file page; the bitmap page
-is x-latched */
-static
-buf_block_t*
-ibuf_bitmap_get_map_page(
-	const page_id_t		page_id,
-	ulint			zip_size,
-	mtr_t*			mtr)
-{
-  return buf_page_get_gen(ibuf_bitmap_page_no_calc(page_id, zip_size),
-                          zip_size, RW_X_LATCH, nullptr,
-                          BUF_GET_POSSIBLY_FREED, mtr);
-}
-
-/************************************************************************//**
-Sets the free bits of the page in the ibuf bitmap. This is done in a separate
-mini-transaction, hence this operation does not restrict further work to only
-ibuf bitmap operations, which would result if the latch to the bitmap page
-were kept. */
-UNIV_INLINE
-void
-ibuf_set_free_bits_low(
-/*===================*/
-	const buf_block_t*	block,	/*!< in: index page; free bits are set if
-					the index is non-clustered and page
-					level is 0 */
-	ulint			val,	/*!< in: value to set: < 4 */
-	mtr_t*			mtr)	/*!< in/out: mtr */
-{
-	ut_ad(mtr->is_named_space(block->page.id().space()));
-	if (!page_is_leaf(block->page.frame)) {
-		return;
-	}
-
-#ifdef UNIV_IBUF_DEBUG
-	ut_a(val <= ibuf_index_page_calc_free(block));
-#endif /* UNIV_IBUF_DEBUG */
-	const page_id_t id(block->page.id());
-
-	if (buf_block_t* bitmap_page = ibuf_bitmap_get_map_page(
-			id, block->zip_size(), mtr)) {
-		ibuf_bitmap_page_set_bits<IBUF_BITMAP_FREE>(
-			bitmap_page, id, block->physical_size(),
-			val, mtr);
-	}
-}
-
-/************************************************************************//**
-Sets the free bit of the page in the ibuf bitmap. This is done in a separate
-mini-transaction, hence this operation does not restrict further work to only
-ibuf bitmap operations, which would result if the latch to the bitmap page
-were kept. */
-void
-ibuf_set_free_bits_func(
-/*====================*/
-	buf_block_t*	block,	/*!< in: index page of a non-clustered index;
-				free bit is reset if page level is 0 */
-#ifdef UNIV_IBUF_DEBUG
-	ulint		max_val,/*!< in: ULINT_UNDEFINED or a maximum
-				value which the bits must have before
-				setting; this is for debugging */
-#endif /* UNIV_IBUF_DEBUG */
-	ulint		val)	/*!< in: value to set: < 4 */
-{
-  if (!page_is_leaf(block->page.frame))
-    return;
-
-  mtr_t	mtr;
-  mtr.start();
-  const page_id_t id(block->page.id());
-  const fil_space_t *space= mtr.set_named_space_id(id.space());
-
-  if (buf_block_t *bitmap_page=
-      ibuf_bitmap_get_map_page(id, block->zip_size(), &mtr))
-  {
-    if (space->purpose != FIL_TYPE_TABLESPACE)
-      mtr.set_log_mode(MTR_LOG_NO_REDO);
-
-#ifdef UNIV_IBUF_DEBUG
-    if (max_val != ULINT_UNDEFINED)
-    {
-      ulint old_val= ibuf_bitmap_page_get_bits(bitmap_page, id,
-                                               IBUF_BITMAP_FREE, &mtr);
-      ut_a(old_val <= max_val);
-    }
-
-    ut_a(val <= ibuf_index_page_calc_free(block));
-#endif /* UNIV_IBUF_DEBUG */
-
-    ibuf_bitmap_page_set_bits<IBUF_BITMAP_FREE>
-      (bitmap_page, id, block->physical_size(), val, &mtr);
-  }
-
-  mtr.commit();
-}
-
-/************************************************************************//**
-Resets the free bits of the page in the ibuf bitmap. This is done in a
-separate mini-transaction, hence this operation does not restrict
-further work to only ibuf bitmap operations, which would result if the
-latch to the bitmap page were kept.  NOTE: The free bits in the insert
-buffer bitmap must never exceed the free space on a page.  It is safe
-to decrement or reset the bits in the bitmap in a mini-transaction
-that is committed before the mini-transaction that affects the free
-space. */
-void
-ibuf_reset_free_bits(
-/*=================*/
-	buf_block_t*	block)	/*!< in: index page; free bits are set to 0
-				if the index is a non-clustered
-				non-unique, and page level is 0 */
-{
-	ibuf_set_free_bits(block, 0, ULINT_UNDEFINED);
-}
-
-/**********************************************************************//**
-Updates the free bits for an uncompressed page to reflect the present
-state.  Does this in the mtr given, which means that the latching
-order rules virtually prevent any further operations for this OS
-thread until mtr is committed.  NOTE: The free bits in the insert
-buffer bitmap must never exceed the free space on a page.  It is safe
-to set the free bits in the same mini-transaction that updated the
-page. */
-void
-ibuf_update_free_bits_low(
-/*======================*/
-	const buf_block_t*	block,		/*!< in: index page */
-	ulint			max_ins_size,	/*!< in: value of
-						maximum insert size
-						with reorganize before
-						the latest operation
-						performed to the page */
-	mtr_t*			mtr)		/*!< in/out: mtr */
-{
-	ulint	before;
-	ulint	after;
-
-	ut_a(!is_buf_block_get_page_zip(block));
-	ut_ad(mtr->is_named_space(block->page.id().space()));
-
-	before = ibuf_index_page_calc_free_bits(srv_page_size,
-						max_ins_size);
-
-	after = ibuf_index_page_calc_free(block);
-
-	/* This approach cannot be used on compressed pages, since the
-	computed value of "before" often does not match the current
-	state of the bitmap.  This is because the free space may
-	increase or decrease when a compressed page is reorganized. */
-	if (before != after) {
-		ibuf_set_free_bits_low(block, after, mtr);
-	}
-}
-
-/**********************************************************************//**
-Updates the free bits for a compressed page to reflect the present
-state.  Does this in the mtr given, which means that the latching
-order rules virtually prevent any further operations for this OS
-thread until mtr is committed.  NOTE: The free bits in the insert
-buffer bitmap must never exceed the free space on a page.  It is safe
-to set the free bits in the same mini-transaction that updated the
-page. */
-void
-ibuf_update_free_bits_zip(
-/*======================*/
-	buf_block_t*	block,	/*!< in/out: index page */
-	mtr_t*		mtr)	/*!< in/out: mtr */
-{
-	ut_ad(page_is_leaf(block->page.frame));
-	ut_ad(block->zip_size());
-
-	ulint after = ibuf_index_page_calc_free_zip(block);
-
-	if (after == 0) {
-		/* We move the page to the front of the buffer pool LRU list:
-		the purpose of this is to prevent those pages to which we
-		cannot make inserts using the insert buffer from slipping
-		out of the buffer pool */
-
-		buf_page_make_young(&block->page);
-	}
-
-	if (buf_block_t* bitmap_page = ibuf_bitmap_get_map_page(
-		block->page.id(), block->zip_size(), mtr)) {
-
-		ibuf_bitmap_page_set_bits<IBUF_BITMAP_FREE>(
-			bitmap_page, block->page.id(),
-			block->physical_size(), after, mtr);
-	}
-}
-
-/**********************************************************************//**
-Updates the free bits for the two pages to reflect the present state.
-Does this in the mtr given, which means that the latching order rules
-virtually prevent any further operations until mtr is committed.
-NOTE: The free bits in the insert buffer bitmap must never exceed the
-free space on a page.  It is safe to set the free bits in the same
-mini-transaction that updated the pages. */
-void
-ibuf_update_free_bits_for_two_pages_low(
-/*====================================*/
-	buf_block_t*	block1,	/*!< in: index page */
-	buf_block_t*	block2,	/*!< in: index page */
-	mtr_t*		mtr)	/*!< in: mtr */
-{
-  ut_ad(mtr->is_named_space(block1->page.id().space()));
-  ut_ad(block1->page.id().space() == block2->page.id().space());
-
-  /* Avoid deadlocks by acquiring multiple bitmap page latches in
-  a consistent order (smaller pointer first). */
-  if (block1 > block2)
-    std::swap(block1, block2);
-
-  ibuf_set_free_bits_low(block1, ibuf_index_page_calc_free(block1), mtr);
-  ibuf_set_free_bits_low(block2, ibuf_index_page_calc_free(block2), mtr);
-}
-
-/** Returns TRUE if the page is one of the fixed address ibuf pages.
-@param[in]	page_id		page id
-@param[in]	zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@return TRUE if a fixed address ibuf i/o page */
-inline bool ibuf_fixed_addr_page(const page_id_t page_id, ulint zip_size)
-{
-	return(page_id == page_id_t(IBUF_SPACE_ID, IBUF_TREE_ROOT_PAGE_NO)
-	       || ibuf_bitmap_page(page_id, zip_size));
-}
-
-/** Checks if a page is a level 2 or 3 page in the ibuf hierarchy of pages.
-Must not be called when recv_no_ibuf_operations==true.
-@param[in]	page_id		page id
-@param[in]	zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@param[in]	x_latch		FALSE if relaxed check (avoid latching the
-bitmap page)
-@param[in,out]	mtr		mtr which will contain an x-latch to the
-bitmap page if the page is not one of the fixed address ibuf pages, or NULL,
-in which case a new transaction is created.
-@return TRUE if level 2 or level 3 page */
-bool
-ibuf_page_low(
-	const page_id_t		page_id,
-	ulint			zip_size,
-#ifdef UNIV_DEBUG
-	bool			x_latch,
-#endif /* UNIV_DEBUG */
-	mtr_t*			mtr)
-{
-	ibool	ret;
-	mtr_t	local_mtr;
-
-	ut_ad(!recv_no_ibuf_operations);
-	ut_ad(x_latch || mtr == NULL);
-
-	if (ibuf_fixed_addr_page(page_id, zip_size)) {
-		return(true);
-	} else if (page_id.space() != IBUF_SPACE_ID) {
-		return(false);
-	}
-
-	compile_time_assert(IBUF_SPACE_ID == 0);
-	ut_ad(fil_system.sys_space->purpose == FIL_TYPE_TABLESPACE);
-
-#ifdef UNIV_DEBUG
-	if (!x_latch) {
-		mtr_start(&local_mtr);
-
-		/* Get the bitmap page without a page latch, so that
-		we will not be violating the latching order when
-		another bitmap page has already been latched by this
-		thread. The page will be buffer-fixed, and thus it
-		cannot be removed or relocated while we are looking at
-		it. The contents of the page could change, but the
-		IBUF_BITMAP_IBUF bit that we are interested in should
-		not be modified by any other thread. Nobody should be
-		calling ibuf_add_free_page() or ibuf_remove_free_page()
-		while the page is linked to the insert buffer b-tree. */
-		buf_block_t* block = buf_page_get_gen(
-			ibuf_bitmap_page_no_calc(page_id, zip_size),
-			zip_size, RW_NO_LATCH, nullptr, BUF_GET, &local_mtr);
-
-		ret = block
-			&& ibuf_bitmap_page_get_bits_low(
-			block->page.frame, page_id, zip_size,
-			MTR_MEMO_BUF_FIX, &local_mtr, IBUF_BITMAP_IBUF);
-
-		mtr_commit(&local_mtr);
-		return(ret);
-	}
-#endif /* UNIV_DEBUG */
-
-	if (mtr == NULL) {
-		mtr = &local_mtr;
-		mtr_start(mtr);
-	}
-
-	buf_block_t *block = ibuf_bitmap_get_map_page(page_id, zip_size,
-						      mtr);
-	ret = block
-		&& ibuf_bitmap_page_get_bits(block->page.frame,
-					     page_id, zip_size,
-					     IBUF_BITMAP_IBUF, mtr);
-
-	if (mtr == &local_mtr) {
-		mtr_commit(mtr);
-	}
-
-	return(ret);
-}
-
-#ifdef UNIV_DEBUG
-# define ibuf_rec_get_page_no(mtr,rec) ibuf_rec_get_page_no_func(mtr,rec)
-#else /* UNIV_DEBUG */
-# define ibuf_rec_get_page_no(mtr,rec) ibuf_rec_get_page_no_func(rec)
-#endif /* UNIV_DEBUG */
+/** first user record field */
+constexpr unsigned IBUF_REC_FIELD_USER= 4;
 
 /********************************************************************//**
 Returns the page number field of an ibuf record.
 @return page number */
-static
-uint32_t
-ibuf_rec_get_page_no_func(
-/*======================*/
-#ifdef UNIV_DEBUG
-	mtr_t*		mtr,	/*!< in: mini-transaction owning rec */
-#endif /* UNIV_DEBUG */
-	const rec_t*	rec)	/*!< in: ibuf record */
+static uint32_t ibuf_rec_get_page_no(const rec_t *rec)
 {
-	const byte*	field;
-	ulint		len;
-
-	ut_ad(mtr->memo_contains_page_flagged(rec, MTR_MEMO_PAGE_X_FIX
-					      | MTR_MEMO_PAGE_S_FIX));
-	ut_ad(ibuf_inside(mtr));
-	ut_ad(rec_get_n_fields_old(rec) > 2);
-
-	field = rec_get_nth_field_old(rec, IBUF_REC_FIELD_MARKER, &len);
-
-	ut_a(len == 1);
-
-	field = rec_get_nth_field_old(rec, IBUF_REC_FIELD_PAGE, &len);
-
-	ut_a(len == 4);
-
-	return(mach_read_from_4(field));
+  return mach_read_from_4(rec + 5);
 }
 
-#ifdef UNIV_DEBUG
-# define ibuf_rec_get_space(mtr,rec) ibuf_rec_get_space_func(mtr,rec)
-#else /* UNIV_DEBUG */
-# define ibuf_rec_get_space(mtr,rec) ibuf_rec_get_space_func(rec)
-#endif /* UNIV_DEBUG */
-
 /********************************************************************//**
-Returns the space id field of an ibuf record. For < 4.1.x format records
-returns 0.
+Returns the space id field of an ibuf record.
 @return space id */
-static
-uint32_t
-ibuf_rec_get_space_func(
-/*====================*/
-#ifdef UNIV_DEBUG
-	mtr_t*		mtr,	/*!< in: mini-transaction owning rec */
-#endif /* UNIV_DEBUG */
-	const rec_t*	rec)	/*!< in: ibuf record */
-{
-	const byte*	field;
-	ulint		len;
-
-	ut_ad(mtr->memo_contains_page_flagged(rec, MTR_MEMO_PAGE_X_FIX
-					      | MTR_MEMO_PAGE_S_FIX));
-	ut_ad(ibuf_inside(mtr));
-	ut_ad(rec_get_n_fields_old(rec) > 2);
-
-	field = rec_get_nth_field_old(rec, IBUF_REC_FIELD_MARKER, &len);
-
-	ut_a(len == 1);
-
-	field = rec_get_nth_field_old(rec, IBUF_REC_FIELD_SPACE, &len);
-
-	ut_a(len == 4);
-
-	return(mach_read_from_4(field));
-}
-
-#ifdef UNIV_DEBUG
-# define ibuf_rec_get_info(mtr,rec,op,comp,info_len,counter)	\
-	ibuf_rec_get_info_func(mtr,rec,op,comp,info_len,counter)
-#else /* UNIV_DEBUG */
-# define ibuf_rec_get_info(mtr,rec,op,comp,info_len,counter)	\
-	ibuf_rec_get_info_func(rec,op,comp,info_len,counter)
-#endif
-/****************************************************************//**
-Get various information about an ibuf record in >= 4.1.x format. */
-static
-void
-ibuf_rec_get_info_func(
-/*===================*/
-#ifdef UNIV_DEBUG
-	mtr_t*		mtr,	/*!< in: mini-transaction owning rec */
-#endif /* UNIV_DEBUG */
-	const rec_t*	rec,		/*!< in: ibuf record */
-	ibuf_op_t*	op,		/*!< out: operation type, or NULL */
-	ibool*		comp,		/*!< out: compact flag, or NULL */
-	ulint*		info_len,	/*!< out: length of info fields at the
-					start of the fourth field, or
-					NULL */
-	ulint*		counter)	/*!< in: counter value, or NULL */
-{
-	const byte*	types;
-	ulint		fields;
-	ulint		len;
-
-	/* Local variables to shadow arguments. */
-	ibuf_op_t	op_local;
-	ibool		comp_local;
-	ulint		info_len_local;
-	ulint		counter_local;
-
-	ut_ad(mtr->memo_contains_page_flagged(rec, MTR_MEMO_PAGE_X_FIX
-					      | MTR_MEMO_PAGE_S_FIX));
-	ut_ad(ibuf_inside(mtr));
-	fields = rec_get_n_fields_old(rec);
-	ut_a(fields > IBUF_REC_FIELD_USER);
-
-	types = rec_get_nth_field_old(rec, IBUF_REC_FIELD_METADATA, &len);
-
-	info_len_local = len % DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE;
-	compile_time_assert(IBUF_REC_INFO_SIZE
-			    < DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE);
-
-	switch (info_len_local) {
-	case 0:
-	case 1:
-		op_local = IBUF_OP_INSERT;
-		comp_local = info_len_local;
-		ut_ad(!counter);
-		counter_local = ULINT_UNDEFINED;
-		break;
-
-	case IBUF_REC_INFO_SIZE:
-		op_local = (ibuf_op_t) types[IBUF_REC_OFFSET_TYPE];
-		comp_local = types[IBUF_REC_OFFSET_FLAGS] & IBUF_REC_COMPACT;
-		counter_local = mach_read_from_2(
-			types + IBUF_REC_OFFSET_COUNTER);
-		break;
-
-	default:
-		ut_error;
-	}
-
-	ut_a(op_local < IBUF_OP_COUNT);
-	ut_a((len - info_len_local) ==
-	     (fields - IBUF_REC_FIELD_USER)
-	     * DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE);
-
-	if (op) {
-		*op = op_local;
-	}
-
-	if (comp) {
-		*comp = comp_local;
-	}
-
-	if (info_len) {
-		*info_len = info_len_local;
-	}
-
-	if (counter) {
-		*counter = counter_local;
-	}
-}
-
-#ifdef UNIV_DEBUG
-# define ibuf_rec_get_op_type(mtr,rec) ibuf_rec_get_op_type_func(mtr,rec)
-#else /* UNIV_DEBUG */
-# define ibuf_rec_get_op_type(mtr,rec) ibuf_rec_get_op_type_func(rec)
-#endif
-
-/****************************************************************//**
-Returns the operation type field of an ibuf record.
-@return operation type */
-static
-ibuf_op_t
-ibuf_rec_get_op_type_func(
-/*======================*/
-#ifdef UNIV_DEBUG
-	mtr_t*		mtr,	/*!< in: mini-transaction owning rec */
-#endif /* UNIV_DEBUG */
-	const rec_t*	rec)	/*!< in: ibuf record */
-{
-	ulint		len;
-
-	ut_ad(mtr->memo_contains_page_flagged(rec, MTR_MEMO_PAGE_X_FIX
-					      | MTR_MEMO_PAGE_S_FIX));
-	ut_ad(ibuf_inside(mtr));
-	ut_ad(rec_get_n_fields_old(rec) > 2);
-
-	(void) rec_get_nth_field_old(rec, IBUF_REC_FIELD_MARKER, &len);
-
-	if (len > 1) {
-		/* This is a < 4.1.x format record */
-
-		return(IBUF_OP_INSERT);
-	} else {
-		ibuf_op_t	op;
-
-		ibuf_rec_get_info(mtr, rec, &op, NULL, NULL, NULL);
-
-		return(op);
-	}
-}
-
-/****************************************************************//**
-Read the first two bytes from a record's fourth field (counter field in new
-records; something else in older records).
-@return "counter" field, or ULINT_UNDEFINED if for some reason it
-can't be read */
-ulint
-ibuf_rec_get_counter(
-/*=================*/
-	const rec_t*	rec)	/*!< in: ibuf record */
+static uint32_t ibuf_rec_get_space(const rec_t *rec)
 {
-	const byte*	ptr;
-	ulint		len;
-
-	if (rec_get_n_fields_old(rec) <= IBUF_REC_FIELD_METADATA) {
-
-		return(ULINT_UNDEFINED);
-	}
-
-	ptr = rec_get_nth_field_old(rec, IBUF_REC_FIELD_METADATA, &len);
-
-	if (len >= 2) {
-
-		return(mach_read_from_2(ptr));
-	} else {
-
-		return(ULINT_UNDEFINED);
-	}
+  return mach_read_from_4(rec);
 }
 
-
-/**
-  Add accumulated operation counts to a permanent array.
-  Both arrays must be of size IBUF_OP_COUNT.
-*/
-static void ibuf_add_ops(Atomic_counter<ulint> *out, const ulint *in)
-{
-  for (auto i = 0; i < IBUF_OP_COUNT; i++)
-    out[i]+= in[i];
-}
-
-
-/****************************************************************//**
-Print operation counts. The array must be of size IBUF_OP_COUNT. */
-static
-void
-ibuf_print_ops(
-/*===========*/
-	const char*			op_name,/*!< in: operation name */
-	const Atomic_counter<ulint>*	ops,	/*!< in: operation counts */
-	FILE*				file)	/*!< in: file where to print */
-{
-	static const char* op_names[] = {
-		"insert",
-		"delete mark",
-		"delete"
-	};
-
-	static_assert(array_elements(op_names) == IBUF_OP_COUNT, "");
-	fputs(op_name, file);
-
-	for (ulint i = 0; i < IBUF_OP_COUNT; i++) {
-		fprintf(file, "%s " ULINTPF "%s", op_names[i],
-			ulint{ops[i]}, (i < (IBUF_OP_COUNT - 1)) ? ", " : "");
-	}
-
-	putc('\n', file);
-}
-
-/********************************************************************//**
-Creates a dummy index for inserting a record to a non-clustered index.
-@return dummy index */
-static
-dict_index_t*
-ibuf_dummy_index_create(
-/*====================*/
-	ulint		n,	/*!< in: number of fields */
-	ibool		comp)	/*!< in: TRUE=use compact record format */
-{
-	dict_table_t*	table;
-	dict_index_t*	index;
-
-	table = dict_table_t::create({C_STRING_WITH_LEN("IBUF_DUMMY")},
-				     nullptr, n, 0,
-				     comp ? DICT_TF_COMPACT : 0, 0);
-
-	index = dict_mem_index_create(table, "IBUF_DUMMY", 0, n);
-
-	/* avoid ut_ad(index->cached) in dict_index_get_n_unique_in_tree */
-	index->cached = TRUE;
-	ut_d(index->is_dummy = true);
-
-	return(index);
-}
 /********************************************************************//**
 Add a column to the dummy index */
 static
@@ -1278,93 +127,79 @@ ibuf_dummy_index_add_col(
 	dict_index_add_col(index, index->table,
 			   dict_table_get_nth_col(index->table, i), len);
 }
-/********************************************************************//**
-Deallocates a dummy index for inserting a record to a non-clustered index. */
+
+/**********************************************************************//**
+Reads to a type the stored information which determines its alphabetical
+ordering and the storage size of an SQL NULL value. This is the >= 4.1.x
+storage format. */
 static
 void
-ibuf_dummy_index_free(
-/*==================*/
-	dict_index_t*	index)	/*!< in, own: dummy index */
+dtype_new_read_for_order_and_null_size(
+/*===================================*/
+	dtype_t*	type,	/*!< in: type struct */
+	const byte*	buf)	/*!< in: buffer for stored type order info */
 {
-	dict_table_t*	table = index->table;
+	type->mtype = buf[0] & 63;
+	type->prtype = buf[1];
 
-	dict_mem_index_free(index);
-	dict_mem_table_free(table);
-}
-
-#ifdef UNIV_DEBUG
-# define ibuf_build_entry_from_ibuf_rec(mtr,ibuf_rec,heap,pindex)	\
-	ibuf_build_entry_from_ibuf_rec_func(mtr,ibuf_rec,heap,pindex)
-#else /* UNIV_DEBUG */
-# define ibuf_build_entry_from_ibuf_rec(mtr,ibuf_rec,heap,pindex)	\
-	ibuf_build_entry_from_ibuf_rec_func(ibuf_rec,heap,pindex)
-#endif
+	if (buf[0] & 128) {
+		type->prtype |= DATA_BINARY_TYPE;
+	}
 
-/*********************************************************************//**
-Builds the entry used to
+	if (buf[4] & 128) {
+		type->prtype |= DATA_NOT_NULL;
+	}
 
-1) IBUF_OP_INSERT: insert into a non-clustered index
+	type->len = mach_read_from_2(buf + 2);
 
-2) IBUF_OP_DELETE_MARK: find the record whose delete-mark flag we need to
-   activate
+	uint32_t charset_coll = (mach_read_from_2(buf + 4) & CHAR_COLL_MASK)
+		<< 16;
 
-3) IBUF_OP_DELETE: find the record we need to delete
+	if (dtype_is_string_type(type->mtype)) {
+		type->prtype |= charset_coll << 16;
 
-when we have the corresponding record in an ibuf index.
+		if (charset_coll == 0) {
+			/* This insert buffer record was inserted before
+			MySQL 4.1.2, and the charset-collation code was not
+			explicitly stored to dtype->prtype at that time. It
+			must be the default charset-collation of this MySQL
+			installation. */
+	                type->prtype |= default_charset_info->number << 16;
+		}
+	}
 
-NOTE that as we copy pointers to fields in ibuf_rec, the caller must
-hold a latch to the ibuf_rec page as long as the entry is used!
+	dtype_set_mblen(type);
+}
 
-@return own: entry to insert to a non-clustered index */
-static
-dtuple_t*
-ibuf_build_entry_from_ibuf_rec_func(
-/*================================*/
-#ifdef UNIV_DEBUG
-	mtr_t*		mtr,	/*!< in: mini-transaction owning rec */
-#endif /* UNIV_DEBUG */
-	const rec_t*	ibuf_rec,	/*!< in: record in an insert buffer */
-	mem_heap_t*	heap,		/*!< in: heap where built */
-	dict_index_t**	pindex)		/*!< out, own: dummy index that
-					describes the entry */
+/** Construct an index entry and an index for applying an operation.
+@param ibuf_rec       change buffer record in an X-latched page
+@param not_redundant  whether another format than ROW_FORMAT=REDUNDANT is used
+@param n_fields       number of index record fields
+@param types          type information
+@param heap           memory heap
+@param index          dummy index metadata
+@return the index entry for applying the operation */
+static dtuple_t *ibuf_entry_build(const rec_t *ibuf_rec, ulint not_redundant,
+                                  ulint n_fields, const byte *types,
+                                  mem_heap_t *heap, dict_index_t *&index)
 {
 	dtuple_t*	tuple;
 	dfield_t*	field;
-	ulint		n_fields;
-	const byte*	types;
 	const byte*	data;
 	ulint		len;
-	ulint		info_len;
-	ulint		i;
-	ulint		comp;
-	dict_index_t*	index;
-
-	ut_ad(mtr->memo_contains_page_flagged(ibuf_rec, MTR_MEMO_PAGE_X_FIX
-					      | MTR_MEMO_PAGE_S_FIX));
-	ut_ad(ibuf_inside(mtr));
-
-	data = rec_get_nth_field_old(ibuf_rec, IBUF_REC_FIELD_MARKER, &len);
-
-	ut_a(len == 1);
-	ut_a(*data == 0);
-	ut_a(rec_get_n_fields_old(ibuf_rec) > IBUF_REC_FIELD_USER);
-
-	n_fields = rec_get_n_fields_old(ibuf_rec) - IBUF_REC_FIELD_USER;
 
 	tuple = dtuple_create(heap, n_fields);
 
-	types = rec_get_nth_field_old(ibuf_rec, IBUF_REC_FIELD_METADATA, &len);
-
-	ibuf_rec_get_info(mtr, ibuf_rec, NULL, &comp, &info_len, NULL);
-
-	index = ibuf_dummy_index_create(n_fields, comp);
-
-	len -= info_len;
-	types += info_len;
-
-	ut_a(len == n_fields * DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE);
+	index = dict_mem_index_create(
+		dict_table_t::create({C_STRING_WITH_LEN("")}, nullptr,
+                                     n_fields, 0,
+				     not_redundant ? DICT_TF_COMPACT : 0, 0),
+                "IBUF_DUMMY", 0, n_fields);
+	/* avoid ut_ad(index->cached) in dict_index_get_n_unique_in_tree */
+	ut_d(index->cached = true);
+	ut_d(index->is_dummy = true);
 
-	for (i = 0; i < n_fields; i++) {
+	for (ulint i = 0; i < n_fields; i++) {
 		field = dtuple_get_nth_field(tuple, i);
 
 		data = rec_get_nth_field_old(
@@ -1373,8 +208,7 @@ ibuf_build_entry_from_ibuf_rec_func(
 		dfield_set_data(field, data, len);
 
 		dtype_new_read_for_order_and_null_size(
-			dfield_get_type(field),
-			types + i * DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE);
+			dfield_get_type(field), types + i * 6);
 
 		ibuf_dummy_index_add_col(index, dfield_get_type(field), len);
 	}
@@ -1384,2216 +218,82 @@ ibuf_build_entry_from_ibuf_rec_func(
 
 	/* Prevent an ut_ad() failure in page_zip_write_rec() by
 	adding system columns to the dummy table pointed to by the
-	dummy secondary index.  The insert buffer is only used for
+	dummy secondary index. The change buffer was only used for
 	secondary indexes, whose records never contain any system
 	columns, such as DB_TRX_ID. */
 	ut_d(dict_table_add_system_columns(index->table, index->table->heap));
-
-	*pindex = index;
-
-	return(tuple);
-}
-
-/******************************************************************//**
-Get the data size.
-@return size of fields */
-UNIV_INLINE
-ulint
-ibuf_rec_get_size(
-/*==============*/
-	const rec_t*	rec,			/*!< in: ibuf record */
-	const byte*	types,			/*!< in: fields */
-	ulint		n_fields,		/*!< in: number of fields */
-	ulint		comp)			/*!< in: 0=ROW_FORMAT=REDUNDANT,
-						nonzero=ROW_FORMAT=COMPACT */
-{
-	ulint	i;
-	ulint	field_offset;
-	ulint	types_offset;
-	ulint	size = 0;
-
-	field_offset = IBUF_REC_FIELD_USER;
-	types_offset = DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE;
-
-	for (i = 0; i < n_fields; i++) {
-		ulint		len;
-		dtype_t		dtype;
-
-		rec_get_nth_field_offs_old(rec, i + field_offset, &len);
-
-		if (len != UNIV_SQL_NULL) {
-			size += len;
-		} else {
-			dtype_new_read_for_order_and_null_size(&dtype, types);
-
-			size += dtype_get_sql_null_size(&dtype, comp);
-		}
-
-		types += types_offset;
-	}
-
-	return(size);
-}
-
-#ifdef UNIV_DEBUG
-# define ibuf_rec_get_volume(mtr,rec) ibuf_rec_get_volume_func(mtr,rec)
-#else /* UNIV_DEBUG */
-# define ibuf_rec_get_volume(mtr,rec) ibuf_rec_get_volume_func(rec)
-#endif
-
-/********************************************************************//**
-Returns the space taken by a stored non-clustered index entry if converted to
-an index record.
-@return size of index record in bytes + an upper limit of the space
-taken in the page directory */
-static
-ulint
-ibuf_rec_get_volume_func(
-/*=====================*/
-#ifdef UNIV_DEBUG
-	mtr_t*		mtr,	/*!< in: mini-transaction owning rec */
-#endif /* UNIV_DEBUG */
-	const rec_t*	ibuf_rec)/*!< in: ibuf record */
-{
-	ulint		len;
-	const byte*	data;
-	const byte*	types;
-	ulint		n_fields;
-	ulint		data_size;
-	ulint		comp;
-	ibuf_op_t	op;
-	ulint		info_len;
-
-	ut_ad(mtr->memo_contains_page_flagged(ibuf_rec, MTR_MEMO_PAGE_X_FIX
-					      | MTR_MEMO_PAGE_S_FIX));
-	ut_ad(ibuf_inside(mtr));
-	ut_ad(rec_get_n_fields_old(ibuf_rec) > 2);
-
-	data = rec_get_nth_field_old(ibuf_rec, IBUF_REC_FIELD_MARKER, &len);
-	ut_a(len == 1);
-	ut_a(*data == 0);
-
-	types = rec_get_nth_field_old(
-		ibuf_rec, IBUF_REC_FIELD_METADATA, &len);
-
-	ibuf_rec_get_info(mtr, ibuf_rec, &op, &comp, &info_len, NULL);
-
-	if (op == IBUF_OP_DELETE_MARK || op == IBUF_OP_DELETE) {
-		/* Delete-marking a record doesn't take any
-		additional space, and while deleting a record
-		actually frees up space, we have to play it safe and
-		pretend it takes no additional space (the record
-		might not exist, etc.).  */
-
-		return(0);
-	} else if (comp) {
-		dtuple_t*	entry;
-		ulint		volume;
-		dict_index_t*	dummy_index;
-		mem_heap_t*	heap = mem_heap_create(500);
-
-		entry = ibuf_build_entry_from_ibuf_rec(mtr, ibuf_rec,
-			heap, &dummy_index);
-
-		volume = rec_get_converted_size(dummy_index, entry, 0);
-
-		ibuf_dummy_index_free(dummy_index);
-		mem_heap_free(heap);
-
-		return(volume + page_dir_calc_reserved_space(1));
-	}
-
-	types += info_len;
-	n_fields = rec_get_n_fields_old(ibuf_rec)
-		- IBUF_REC_FIELD_USER;
-
-	data_size = ibuf_rec_get_size(ibuf_rec, types, n_fields, comp);
-
-	return(data_size + rec_get_converted_extra_size(data_size, n_fields, 0)
-	       + page_dir_calc_reserved_space(1));
-}
-
-/*********************************************************************//**
-Builds the tuple to insert to an ibuf tree when we have an entry for a
-non-clustered index.
-
-NOTE that the original entry must be kept because we copy pointers to
-its fields.
-
-@return own: entry to insert into an ibuf index tree */
-static
-dtuple_t*
-ibuf_entry_build(
-/*=============*/
-	ibuf_op_t	op,	/*!< in: operation type */
-	dict_index_t*	index,	/*!< in: non-clustered index */
-	const dtuple_t*	entry,	/*!< in: entry for a non-clustered index */
-	ulint		space,	/*!< in: space id */
-	ulint		page_no,/*!< in: index page number where entry should
-				be inserted */
-	ulint		counter,/*!< in: counter value;
-				ULINT_UNDEFINED=not used */
-	mem_heap_t*	heap)	/*!< in: heap into which to build */
-{
-	dtuple_t*	tuple;
-	dfield_t*	field;
-	const dfield_t*	entry_field;
-	ulint		n_fields;
-	byte*		buf;
-	byte*		ti;
-	byte*		type_info;
-	ulint		i;
-
-	ut_ad(counter != ULINT_UNDEFINED || op == IBUF_OP_INSERT);
-	ut_ad(counter == ULINT_UNDEFINED || counter <= 0xFFFF);
-	ut_ad(op < IBUF_OP_COUNT);
-
-	/* We have to build a tuple with the following fields:
-
-	1-4) These are described at the top of this file.
-
-	5) The rest of the fields are copied from the entry.
-
-	All fields in the tuple are ordered like the type binary in our
-	insert buffer tree. */
-
-	n_fields = dtuple_get_n_fields(entry);
-
-	tuple = dtuple_create(heap, n_fields + IBUF_REC_FIELD_USER);
-
-	/* 1) Space Id */
-
-	field = dtuple_get_nth_field(tuple, IBUF_REC_FIELD_SPACE);
-
-	buf = static_cast<byte*>(mem_heap_alloc(heap, 4));
-
-	mach_write_to_4(buf, space);
-
-	dfield_set_data(field, buf, 4);
-
-	/* 2) Marker byte */
-
-	field = dtuple_get_nth_field(tuple, IBUF_REC_FIELD_MARKER);
-
-	buf = static_cast<byte*>(mem_heap_alloc(heap, 1));
-
-	/* We set the marker byte zero */
-
-	mach_write_to_1(buf, 0);
-
-	dfield_set_data(field, buf, 1);
-
-	/* 3) Page number */
-
-	field = dtuple_get_nth_field(tuple, IBUF_REC_FIELD_PAGE);
-
-	buf = static_cast<byte*>(mem_heap_alloc(heap, 4));
-
-	mach_write_to_4(buf, page_no);
-
-	dfield_set_data(field, buf, 4);
-
-	/* 4) Type info, part #1 */
-
-	if (counter == ULINT_UNDEFINED) {
-		i = dict_table_is_comp(index->table) ? 1 : 0;
-	} else {
-		ut_ad(counter <= 0xFFFF);
-		i = IBUF_REC_INFO_SIZE;
-	}
-
-	ti = type_info = static_cast<byte*>(
-		mem_heap_alloc(
-			heap,
-			i + n_fields * DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE));
-
-	switch (i) {
-	default:
-		ut_error;
-		break;
-	case 1:
-		/* set the flag for ROW_FORMAT=COMPACT */
-		*ti++ = 0;
-		/* fall through */
-	case 0:
-		/* the old format does not allow delete buffering */
-		ut_ad(op == IBUF_OP_INSERT);
-		break;
-	case IBUF_REC_INFO_SIZE:
-		mach_write_to_2(ti + IBUF_REC_OFFSET_COUNTER, counter);
-
-		ti[IBUF_REC_OFFSET_TYPE] = (byte) op;
-		ti[IBUF_REC_OFFSET_FLAGS] = dict_table_is_comp(index->table)
-			? IBUF_REC_COMPACT : 0;
-		ti += IBUF_REC_INFO_SIZE;
-		break;
-	}
-
-	/* 5+) Fields from the entry */
-
-	for (i = 0; i < n_fields; i++) {
-		ulint			fixed_len;
-		const dict_field_t*	ifield;
-
-		field = dtuple_get_nth_field(tuple, i + IBUF_REC_FIELD_USER);
-		entry_field = dtuple_get_nth_field(entry, i);
-		dfield_copy(field, entry_field);
-
-		ifield = dict_index_get_nth_field(index, i);
-		ut_ad(!ifield->descending);
-		/* Prefix index columns of fixed-length columns are of
-		fixed length.  However, in the function call below,
-		dfield_get_type(entry_field) contains the fixed length
-		of the column in the clustered index.  Replace it with
-		the fixed length of the secondary index column. */
-		fixed_len = ifield->fixed_len;
-
-#ifdef UNIV_DEBUG
-		if (fixed_len) {
-			/* dict_index_add_col() should guarantee these */
-			ut_ad(fixed_len <= (ulint)
-			      dfield_get_type(entry_field)->len);
-			if (ifield->prefix_len) {
-				ut_ad(ifield->prefix_len == fixed_len);
-			} else {
-				ut_ad(fixed_len == (ulint)
-				      dfield_get_type(entry_field)->len);
-			}
-		}
-#endif /* UNIV_DEBUG */
-
-		dtype_new_store_for_order_and_null_size(
-			ti, dfield_get_type(entry_field), fixed_len);
-		ti += DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE;
-	}
-
-	/* 4) Type info, part #2 */
-
-	field = dtuple_get_nth_field(tuple, IBUF_REC_FIELD_METADATA);
-
-	dfield_set_data(field, type_info, ulint(ti - type_info));
-
-	/* Set all the types in the new tuple binary */
-
-	dtuple_set_types_binary(tuple, n_fields + IBUF_REC_FIELD_USER);
-
 	return(tuple);
 }
 
-/*********************************************************************//**
-Builds a search tuple used to search buffered inserts for an index page.
-This is for >= 4.1.x format records.
-@return own: search tuple */
-static
-dtuple_t*
-ibuf_search_tuple_build(
-/*====================*/
-	ulint		space,	/*!< in: space id */
-	ulint		page_no,/*!< in: index page number */
-	mem_heap_t*	heap)	/*!< in: heap into which to build */
+/** Removes a page from the free list and frees it to the fsp system.
+@param mtr    mini-transaction
+@return error code
+@retval DB_SUCCESS            if more work may remain to be done
+@retval DB_SUCCESS_LOCKED_REC if everything was freed */
+ATTRIBUTE_COLD static dberr_t ibuf_remove_free_page(mtr_t &mtr)
 {
-	dtuple_t*	tuple;
-	dfield_t*	field;
-	byte*		buf;
-
-	tuple = dtuple_create(heap, IBUF_REC_FIELD_METADATA);
-
-	/* Store the space id in tuple */
-
-	field = dtuple_get_nth_field(tuple, IBUF_REC_FIELD_SPACE);
-
-	buf = static_cast<byte*>(mem_heap_alloc(heap, 4));
-
-	mach_write_to_4(buf, space);
+  log_free_check();
 
-	dfield_set_data(field, buf, 4);
-
-	/* Store the new format record marker byte */
-
-	field = dtuple_get_nth_field(tuple, IBUF_REC_FIELD_MARKER);
-
-	buf = static_cast<byte*>(mem_heap_alloc(heap, 1));
-
-	mach_write_to_1(buf, 0);
-
-	dfield_set_data(field, buf, 1);
-
-	/* Store the page number in tuple */
-
-	field = dtuple_get_nth_field(tuple, IBUF_REC_FIELD_PAGE);
-
-	buf = static_cast<byte*>(mem_heap_alloc(heap, 4));
-
-	mach_write_to_4(buf, page_no);
-
-	dfield_set_data(field, buf, 4);
-
-	dtuple_set_types_binary(tuple, IBUF_REC_FIELD_METADATA);
-
-	return(tuple);
-}
-
-/*********************************************************************//**
-Checks if there are enough pages in the free list of the ibuf tree that we
-dare to start a pessimistic insert to the insert buffer.
-@return whether enough free pages in list */
-static inline bool ibuf_data_enough_free_for_insert()
-{
-	mysql_mutex_assert_owner(&ibuf_mutex);
-
-	/* We want a big margin of free pages, because a B-tree can sometimes
-	grow in size also if records are deleted from it, as the node pointers
-	can change, and we must make sure that we are able to delete the
-	inserts buffered for pages that we read to the buffer pool, without
-	any risk of running out of free space in the insert buffer. */
-
-	return(ibuf.free_list_len >= (ibuf.size / 2) + 3 * ibuf.height);
-}
-
-/*********************************************************************//**
-Checks if there are enough pages in the free list of the ibuf tree that we
-should remove them and free to the file space management.
-@return TRUE if enough free pages in list */
-UNIV_INLINE
-ibool
-ibuf_data_too_much_free(void)
-/*=========================*/
-{
-	mysql_mutex_assert_owner(&ibuf_mutex);
-
-	return(ibuf.free_list_len >= 3 + (ibuf.size / 2) + 3 * ibuf.height);
-}
-
-/** Allocate a change buffer page.
-@retval true on success
-@retval false if no space left */
-static bool ibuf_add_free_page()
-{
-	mtr_t		mtr;
-	page_t*		header_page;
-	buf_block_t*	block;
-
-	mtr.start();
-	/* Acquire the fsp latch before the ibuf header, obeying the latching
-	order */
-	mtr.x_lock_space(fil_system.sys_space);
-	header_page = ibuf_header_page_get(&mtr);
-	if (!header_page) {
-		mtr.commit();
-		return false;
-	}
-
-	/* Allocate a new page: NOTE that if the page has been a part of a
-	non-clustered index which has subsequently been dropped, then the
-	page may have buffered inserts in the insert buffer, and these
-	should be deleted from there. These get deleted when the page
-	allocation creates the page in buffer. Thus the call below may end
-	up calling the insert buffer routines and, as we yet have no latches
-	to insert buffer tree pages, these routines can run without a risk
-	of a deadlock. This is the reason why we created a special ibuf
-	header page apart from the ibuf tree. */
-
-	dberr_t err;
-	block = fseg_alloc_free_page_general(
-		header_page + IBUF_HEADER + IBUF_TREE_SEG_HEADER, 0, FSP_UP,
-		false, &mtr, &mtr, &err);
-
-	if (!block) {
-		mtr.commit();
-		return false;
-	}
-
-	ut_ad(block->page.lock.not_recursive());
-	ibuf_enter(&mtr);
-	mysql_mutex_lock(&ibuf_mutex);
-
-	mtr.write<2>(*block, block->page.frame + FIL_PAGE_TYPE,
-		     FIL_PAGE_IBUF_FREE_LIST);
-	buf_block_t* ibuf_root = ibuf_tree_root_get(&mtr);
-	if (UNIV_UNLIKELY(!ibuf_root)) {
-corrupted:
-		/* Do not bother to try to free the allocated block, because
-		the change buffer is seriously corrupted already. */
-		mysql_mutex_unlock(&ibuf_mutex);
-		ibuf_mtr_commit(&mtr);
-		return false;
-	}
-
-	/* Add the page to the free list and update the ibuf size data */
-
-	err = flst_add_last(ibuf_root, PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST,
-			    block, PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST_NODE,
-			    &mtr);
-	if (UNIV_UNLIKELY(err != DB_SUCCESS)) {
-		goto corrupted;
-	}
-
-	/* Set the bit indicating that this page is now an ibuf tree page
-	(level 2 page) */
-
-	const page_id_t page_id(block->page.id());
-	buf_block_t* bitmap_page = ibuf_bitmap_get_map_page(page_id, 0, &mtr);
-
-	if (UNIV_UNLIKELY(!bitmap_page)) {
-		goto corrupted;
-	}
-
-	ibuf.seg_size++;
-	ibuf.free_list_len++;
-
-	mysql_mutex_unlock(&ibuf_mutex);
-
-	ibuf_bitmap_page_set_bits<IBUF_BITMAP_IBUF>(bitmap_page, page_id,
-						    srv_page_size, true, &mtr);
-	ibuf_mtr_commit(&mtr);
-	return true;
-}
-
-/*********************************************************************//**
-Removes a page from the free list and frees it to the fsp system. */
-static void ibuf_remove_free_page()
-{
-	mtr_t	mtr;
-	mtr_t	mtr2;
-	page_t*	header_page;
-
-	log_free_check();
-
-	mtr_start(&mtr);
-	/* Acquire the fsp latch before the ibuf header, obeying the latching
-	order */
-
-	mtr.x_lock_space(fil_system.sys_space);
-	header_page = ibuf_header_page_get(&mtr);
-
-	/* Prevent pessimistic inserts to insert buffer trees for a while */
-	ibuf_enter(&mtr);
-	mysql_mutex_lock(&ibuf_pessimistic_insert_mutex);
-	mysql_mutex_lock(&ibuf_mutex);
-
-	if (!header_page || !ibuf_data_too_much_free()) {
-early_exit:
-		mysql_mutex_unlock(&ibuf_mutex);
-		mysql_mutex_unlock(&ibuf_pessimistic_insert_mutex);
-
-		ibuf_mtr_commit(&mtr);
-
-		return;
-	}
-
-	ibuf_mtr_start(&mtr2);
-
-	buf_block_t* root = ibuf_tree_root_get(&mtr2);
-
-	if (UNIV_UNLIKELY(!root)) {
-		ibuf_mtr_commit(&mtr2);
-		goto early_exit;
-	}
-
-	mysql_mutex_unlock(&ibuf_mutex);
-
-	const uint32_t page_no = flst_get_last(PAGE_HEADER
-					       + PAGE_BTR_IBUF_FREE_LIST
-					       + root->page.frame).page;
-
-	/* NOTE that we must release the latch on the ibuf tree root
-	because in fseg_free_page we access level 1 pages, and the root
-	is a level 2 page. */
-
-	ibuf_mtr_commit(&mtr2);
-	ibuf_exit(&mtr);
-
-	/* Since pessimistic inserts were prevented, we know that the
-	page is still in the free list. NOTE that also deletes may take
-	pages from the free list, but they take them from the start, and
-	the free list was so long that they cannot have taken the last
-	page from it. */
-
-	compile_time_assert(IBUF_SPACE_ID == 0);
-	const page_id_t	page_id{IBUF_SPACE_ID, page_no};
-	buf_block_t* bitmap_page = nullptr;
-	dberr_t err = fseg_free_page(
-		header_page + IBUF_HEADER + IBUF_TREE_SEG_HEADER,
-		fil_system.sys_space, page_no, &mtr);
-
-	if (err != DB_SUCCESS) {
-		goto func_exit;
-	}
-
-	ibuf_enter(&mtr);
-
-	mysql_mutex_lock(&ibuf_mutex);
-
-	root = ibuf_tree_root_get(&mtr, &err);
-	if (UNIV_UNLIKELY(!root)) {
-		mysql_mutex_unlock(&ibuf_pessimistic_insert_mutex);
-		goto func_exit;
-	}
-
-	ut_ad(page_no == flst_get_last(PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST
-				       + root->page.frame).page);
-
-	/* Remove the page from the free list and update the ibuf size data */
-	if (buf_block_t* block =
-	    buf_page_get_gen(page_id, 0, RW_X_LATCH, nullptr, BUF_GET,
-			     &mtr, &err)) {
-		err = flst_remove(root, PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST,
-				  block,
-				  PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST_NODE,
-				  &mtr);
-	}
-
-	mysql_mutex_unlock(&ibuf_pessimistic_insert_mutex);
+  mtr.start();
 
-	if (err == DB_SUCCESS) {
-		ibuf.seg_size--;
-		ibuf.free_list_len--;
-		bitmap_page = ibuf_bitmap_get_map_page(page_id, 0, &mtr);
-	}
+  mtr.x_lock_space(fil_system.sys_space);
+  dberr_t err;
+  buf_block_t* header= buf_page_get_gen(ibuf_header, 0, RW_X_LATCH, nullptr,
+                                        BUF_GET, &mtr, &err);
 
+  if (!header)
+  {
 func_exit:
-	mysql_mutex_unlock(&ibuf_mutex);
-
-	if (bitmap_page) {
-		/* Set the bit indicating that this page is no more an
-		ibuf tree page (level 2 page) */
-		ibuf_bitmap_page_set_bits<IBUF_BITMAP_IBUF>(
-			bitmap_page, page_id, srv_page_size, false, &mtr);
-	}
-
-	if (err == DB_SUCCESS) {
-		buf_page_free(fil_system.sys_space, page_no, &mtr);
-	}
-
-	ibuf_mtr_commit(&mtr);
-}
-
-/***********************************************************************//**
-Frees excess pages from the ibuf free list. This function is called when an OS
-thread calls fsp services to allocate a new file segment, or a new page to a
-file segment, and the thread did not own the fsp latch before this call. */
-void
-ibuf_free_excess_pages(void)
-/*========================*/
-{
-	/* Free at most a few pages at a time, so that we do not delay the
-	requested service too much */
-
-	for (ulint i = 0; i < 4; i++) {
-
-		ibool	too_much_free;
-
-		mysql_mutex_lock(&ibuf_mutex);
-		too_much_free = ibuf_data_too_much_free();
-		mysql_mutex_unlock(&ibuf_mutex);
-
-		if (!too_much_free) {
-			return;
-		}
-
-		ibuf_remove_free_page();
-	}
-}
-
-#ifdef UNIV_DEBUG
-# define ibuf_get_merge_page_nos(contract,rec,mtr,ids,pages,n_stored) \
-	ibuf_get_merge_page_nos_func(contract,rec,mtr,ids,pages,n_stored)
-#else /* UNIV_DEBUG */
-# define ibuf_get_merge_page_nos(contract,rec,mtr,ids,pages,n_stored) \
-	ibuf_get_merge_page_nos_func(contract,rec,ids,pages,n_stored)
-#endif /* UNIV_DEBUG */
-
-/*********************************************************************//**
-Reads page numbers from a leaf in an ibuf tree.
-@return a lower limit for the combined volume of records which will be
-merged */
-static
-ulint
-ibuf_get_merge_page_nos_func(
-/*=========================*/
-	ibool		contract,/*!< in: TRUE if this function is called to
-				contract the tree, FALSE if this is called
-				when a single page becomes full and we look
-				if it pays to read also nearby pages */
-	const rec_t*	rec,	/*!< in: insert buffer record */
-#ifdef UNIV_DEBUG
-	mtr_t*		mtr,	/*!< in: mini-transaction holding rec */
-#endif /* UNIV_DEBUG */
-	uint32_t*	space_ids,/*!< in/out: space id's of the pages */
-	uint32_t*	page_nos,/*!< in/out: buffer for at least
-				IBUF_MAX_N_PAGES_MERGED many page numbers;
-				the page numbers are in an ascending order */
-	ulint*		n_stored)/*!< out: number of page numbers stored to
-				page_nos in this function */
-{
-	uint32_t prev_page_no;
-	uint32_t prev_space_id;
-	uint32_t first_page_no;
-	uint32_t first_space_id;
-	uint32_t rec_page_no;
-	uint32_t rec_space_id;
-	ulint	sum_volumes;
-	ulint	volume_for_page;
-	ulint	rec_volume;
-	ulint	limit;
-	ulint	n_pages;
-
-	ut_ad(mtr->memo_contains_page_flagged(rec, MTR_MEMO_PAGE_X_FIX
-					      | MTR_MEMO_PAGE_S_FIX));
-	ut_ad(ibuf_inside(mtr));
-
-	*n_stored = 0;
-
-	if (page_rec_is_supremum(rec)) {
-
-		rec = page_rec_get_prev_const(rec);
-		if (UNIV_UNLIKELY(!rec)) {
-corruption:
-			ut_ad("corrupted page" == 0);
-			return 0;
-		}
-	}
-
-	if (page_rec_is_infimum(rec)) {
-		rec = page_rec_get_next_const(rec);
-		if (!rec || page_rec_is_supremum(rec)) {
-			return 0;
-		}
-	}
-
-	limit = ut_min(IBUF_MAX_N_PAGES_MERGED,
-		       buf_pool_get_curr_size() / 4);
-
-	first_page_no = ibuf_rec_get_page_no(mtr, rec);
-	first_space_id = ibuf_rec_get_space(mtr, rec);
-	n_pages = 0;
-	prev_page_no = 0;
-	prev_space_id = 0;
-
-	/* Go backwards from the first rec until we reach the border of the
-	'merge area', or the page start or the limit of storeable pages is
-	reached */
-
-	while (!page_rec_is_infimum(rec) && UNIV_LIKELY(n_pages < limit)) {
-
-		rec_page_no = ibuf_rec_get_page_no(mtr, rec);
-		rec_space_id = ibuf_rec_get_space(mtr, rec);
-
-		if (rec_space_id != first_space_id
-		    || (rec_page_no / IBUF_MERGE_AREA)
-		    != (first_page_no / IBUF_MERGE_AREA)) {
-
-			break;
-		}
-
-		if (rec_page_no != prev_page_no
-		    || rec_space_id != prev_space_id) {
-			n_pages++;
-		}
-
-		prev_page_no = rec_page_no;
-		prev_space_id = rec_space_id;
-
-		if (UNIV_UNLIKELY(!(rec = page_rec_get_prev_const(rec)))) {
-			goto corruption;
-		}
-	}
-
-	rec = page_rec_get_next_const(rec);
-
-	/* At the loop start there is no prev page; we mark this with a pair
-	of space id, page no (0, 0) for which there can never be entries in
-	the insert buffer */
-
-	prev_page_no = 0;
-	prev_space_id = 0;
-	sum_volumes = 0;
-	volume_for_page = 0;
-
-	while (*n_stored < limit && rec) {
-		if (page_rec_is_supremum(rec)) {
-			/* When no more records available, mark this with
-			another 'impossible' pair of space id, page no */
-			rec_page_no = 1;
-			rec_space_id = 0;
-		} else {
-			rec_page_no = ibuf_rec_get_page_no(mtr, rec);
-			rec_space_id = ibuf_rec_get_space(mtr, rec);
-			/* In the system tablespace the smallest
-			possible secondary index leaf page number is
-			bigger than FSP_DICT_HDR_PAGE_NO (7).
-			In all tablespaces, pages 0 and 1 are reserved
-			for the allocation bitmap and the change
-			buffer bitmap. In file-per-table tablespaces,
-			a file segment inode page will be created at
-			page 2 and the clustered index tree is created
-			at page 3.  So for file-per-table tablespaces,
-			page 4 is the smallest possible secondary
-			index leaf page. CREATE TABLESPACE also initially
-			uses pages 2 and 3 for the first created table,
-			but that table may be dropped, allowing page 2
-			to be reused for a secondary index leaf page.
-			To keep this assertion simple, just
-			make sure the page is >= 2. */
-			ut_ad(rec_page_no >= FSP_FIRST_INODE_PAGE_NO);
-		}
-
-#ifdef UNIV_IBUF_DEBUG
-		ut_a(*n_stored < IBUF_MAX_N_PAGES_MERGED);
-#endif
-		if ((rec_space_id != prev_space_id
-		     || rec_page_no != prev_page_no)
-		    && (prev_space_id != 0 || prev_page_no != 0)) {
-
-			if (contract
-			    || (prev_page_no == first_page_no
-				&& prev_space_id == first_space_id)
-			    || (volume_for_page
-				> ((IBUF_MERGE_THRESHOLD - 1)
-				   * 4U << srv_page_size_shift
-				   / IBUF_PAGE_SIZE_PER_FREE_SPACE)
-				/ IBUF_MERGE_THRESHOLD)) {
-
-				space_ids[*n_stored] = prev_space_id;
-				page_nos[*n_stored] = prev_page_no;
-
-				(*n_stored)++;
-
-				sum_volumes += volume_for_page;
-			}
-
-			if (rec_space_id != first_space_id
-			    || rec_page_no / IBUF_MERGE_AREA
-			    != first_page_no / IBUF_MERGE_AREA) {
-
-				break;
-			}
-
-			volume_for_page = 0;
-		}
-
-		if (rec_page_no == 1 && rec_space_id == 0) {
-			/* Supremum record */
-
-			break;
-		}
-
-		rec_volume = ibuf_rec_get_volume(mtr, rec);
-
-		volume_for_page += rec_volume;
-
-		prev_page_no = rec_page_no;
-		prev_space_id = rec_space_id;
-
-		rec = page_rec_get_next_const(rec);
-	}
-
-#ifdef UNIV_IBUF_DEBUG
-	ut_a(*n_stored <= IBUF_MAX_N_PAGES_MERGED);
-#endif
-#if 0
-	fprintf(stderr, "Ibuf merge batch %lu pages %lu volume\n",
-		*n_stored, sum_volumes);
-#endif
-	return(sum_volumes);
-}
-
-/*******************************************************************//**
-Get the matching records for space id.
-@return current rec or NULL */
-static	MY_ATTRIBUTE((nonnull, warn_unused_result))
-const rec_t*
-ibuf_get_user_rec(
-/*===============*/
-	btr_pcur_t*	pcur,		/*!< in: the current cursor */
-	mtr_t*		mtr)		/*!< in: mini transaction */
-{
-	do {
-		const rec_t* rec = btr_pcur_get_rec(pcur);
-
-		if (page_rec_is_user_rec(rec)) {
-			return(rec);
-		}
-	} while (btr_pcur_move_to_next(pcur, mtr));
-
-	return(NULL);
-}
-
-/*********************************************************************//**
-Reads page numbers for a space id from an ibuf tree.
-@return a lower limit for the combined volume of records which will be
-merged */
-static	MY_ATTRIBUTE((nonnull, warn_unused_result))
-ulint
-ibuf_get_merge_pages(
-/*=================*/
-	btr_pcur_t*	pcur,	/*!< in/out: cursor */
-	uint32_t	space,	/*!< in: space for which to merge */
-	ulint		limit,	/*!< in: max page numbers to read */
-	uint32_t*	pages,	/*!< out: pages read */
-	uint32_t*	spaces,	/*!< out: spaces read */
-	ulint*		n_pages,/*!< out: number of pages read */
-	mtr_t*		mtr)	/*!< in: mini transaction */
-{
-	const rec_t*	rec;
-	ulint		volume = 0;
-
-	*n_pages = 0;
-
-	while ((rec = ibuf_get_user_rec(pcur, mtr)) != 0
-	       && ibuf_rec_get_space(mtr, rec) == space
-	       && *n_pages < limit) {
-
-		uint32_t page_no = ibuf_rec_get_page_no(mtr, rec);
-
-		if (*n_pages == 0 || pages[*n_pages - 1] != page_no) {
-			spaces[*n_pages] = space;
-			pages[*n_pages] = page_no;
-			++*n_pages;
-		}
-
-		volume += ibuf_rec_get_volume(mtr, rec);
-
-		btr_pcur_move_to_next(pcur, mtr);
-	}
-
-	return(volume);
-}
-
-/**
-Delete a change buffer record.
-@param[in]	page_id		page identifier
-@param[in,out]	pcur		persistent cursor positioned on the record
-@param[in]	search_tuple	search key for (space,page_no)
-@param[in,out]	mtr		mini-transaction
-@return whether mtr was committed (due to pessimistic operation) */
-static MY_ATTRIBUTE((warn_unused_result, nonnull))
-bool ibuf_delete_rec(const page_id_t page_id, btr_pcur_t* pcur,
-		     const dtuple_t* search_tuple, mtr_t* mtr);
-
-/** Delete the change buffer records for the given page id
-@param page_id page identifier */
-static void ibuf_delete_recs(const page_id_t page_id)
-{
-  if (!ibuf.index || srv_read_only_mode)
-    return;
-  dfield_t dfield[IBUF_REC_FIELD_METADATA];
-  dtuple_t tuple {0,IBUF_REC_FIELD_METADATA,IBUF_REC_FIELD_METADATA,
-                  dfield,0,nullptr
-#ifdef UNIV_DEBUG
-                  ,DATA_TUPLE_MAGIC_N
-#endif
-  };
-  byte space_id[4], page_no[4];
-
-  mach_write_to_4(space_id, page_id.space());
-  mach_write_to_4(page_no, page_id.page_no());
+    mtr.commit();
+    return err;
+  }
 
-  dfield_set_data(&dfield[0], space_id, 4);
-  dfield_set_data(&dfield[1], field_ref_zero, 1);
-  dfield_set_data(&dfield[2], page_no, 4);
-  dtuple_set_types_binary(&tuple, IBUF_REC_FIELD_METADATA);
+  buf_block_t *root= buf_page_get_gen(ibuf_root, 0, RW_X_LATCH,
+                                      nullptr, BUF_GET, &mtr, &err);
 
-  mtr_t mtr;
-loop:
-  btr_pcur_t pcur;
-  pcur.btr_cur.page_cur.index= ibuf.index;
-  ibuf_mtr_start(&mtr);
-  if (btr_pcur_open(&tuple, PAGE_CUR_GE, BTR_MODIFY_LEAF, &pcur, 0, &mtr))
+  if (UNIV_UNLIKELY(!root))
     goto func_exit;
-  if (!btr_pcur_is_on_user_rec(&pcur))
-  {
-    ut_ad(btr_pcur_is_after_last_on_page(&pcur));
-    goto func_exit;
-  }
 
-  for (;;)
+  const uint32_t page_no= flst_get_last(PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST +
+                                        root->page.frame).page;
+  if (page_no == FIL_NULL)
   {
-    ut_ad(btr_pcur_is_on_user_rec(&pcur));
-    const rec_t* ibuf_rec = btr_pcur_get_rec(&pcur);
-    if (ibuf_rec_get_space(&mtr, ibuf_rec) != page_id.space()
-        || ibuf_rec_get_page_no(&mtr, ibuf_rec) != page_id.page_no())
-      break;
-    /* Delete the record from ibuf */
-    if (ibuf_delete_rec(page_id, &pcur, &tuple, &mtr))
-    {
-      /* Deletion was pessimistic and mtr was committed:
-      we start from the beginning again */
-      ut_ad(mtr.has_committed());
-      goto loop;
-    }
-
-    if (btr_pcur_is_after_last_on_page(&pcur))
-    {
-      ibuf_mtr_commit(&mtr);
-      btr_pcur_close(&pcur);
-      goto loop;
-    }
+    mtr.set_modified(*root);
+    fsp_init_file_page(fil_system.sys_space, root, &mtr);
+    err= DB_SUCCESS_LOCKED_REC;
+    goto func_exit;
   }
-func_exit:
-  ibuf_mtr_commit(&mtr);
-  btr_pcur_close(&pcur);
-}
-
-/** Merge the change buffer to some pages. */
-static void ibuf_read_merge_pages(const uint32_t* space_ids,
-				  const uint32_t* page_nos, ulint n_stored)
-{
-	for (ulint i = 0; i < n_stored; i++) {
-		const uint32_t space_id = space_ids[i];
-		fil_space_t* s = fil_space_t::get(space_id);
-		if (!s) {
-tablespace_deleted:
-			/* The tablespace was not found: remove all
-			entries for it */
-			ibuf_delete_for_discarded_space(space_id);
-			while (i + 1 < n_stored
-			       && space_ids[i + 1] == space_id) {
-				i++;
-			}
-			continue;
-		}
-
-		const ulint zip_size = s->zip_size(), size = s->size;
-		s->release();
-		mtr_t mtr;
-
-		if (UNIV_LIKELY(page_nos[i] < size)) {
-			mtr.start();
-			dberr_t err;
-			buf_block_t *block =
-			buf_page_get_gen(page_id_t(space_id, page_nos[i]),
-					 zip_size, RW_X_LATCH, nullptr,
-					 BUF_GET_POSSIBLY_FREED,
-					 &mtr, &err, true);
-			bool remove = !block
-				|| fil_page_get_type(block->page.frame)
-				!= FIL_PAGE_INDEX
-				|| !page_is_leaf(block->page.frame);
-			mtr.commit();
-			if (err == DB_TABLESPACE_DELETED) {
-				goto tablespace_deleted;
-			}
-			if (!remove) {
-				continue;
-			}
-		}
-
-		if (srv_shutdown_state == SRV_SHUTDOWN_NONE
-		    || srv_fast_shutdown) {
-			continue;
-		}
-
-		/* The following code works around a hang when the
-		change buffer is corrupted, likely due to the
-		failure of ibuf_merge_or_delete_for_page() to
-		invoke ibuf_delete_recs() if (!bitmap_bits).
-
-		It also introduced corruption by itself in the
-		following scenario:
-
-		(1) We merged buffered changes in buf_page_get_gen()
-		(2) We committed the mini-transaction
-		(3) Redo log and the page with the merged changes is written
-		(4) A write completion callback thread evicts the page.
-		(5) Other threads buffer changes for that page.
-		(6) We will wrongly discard those newly buffered changes below.
-
-		To prevent this scenario, we will only invoke this code
-		on shutdown. A call to ibuf_max_size_update(0) will cause
-		ibuf_insert_low() to refuse to insert anything into the
-		change buffer. */
-
-		/* Prevent an infinite loop, by removing entries from
-		the change buffer in the case the bitmap bits were
-		wrongly clear even though buffered changes exist. */
-		ibuf_delete_recs(page_id_t(space_ids[i], page_nos[i]));
-	}
-}
-
-/** Contract the change buffer by reading pages to the buffer pool.
-@return a lower limit for the combined size in bytes of entries which
-will be merged from ibuf trees to the pages read
-@retval 0 if ibuf.empty */
-ulint ibuf_contract()
-{
-	mtr_t		mtr;
-	btr_cur_t	cur;
-	ulint		sum_sizes;
-	uint32_t	page_nos[IBUF_MAX_N_PAGES_MERGED];
-	uint32_t	space_ids[IBUF_MAX_N_PAGES_MERGED];
-
-	ibuf_mtr_start(&mtr);
-
-	if (cur.open_leaf(true, ibuf.index, BTR_SEARCH_LEAF, &mtr) !=
-	    DB_SUCCESS) {
-		return 0;
-	}
-
-	ut_ad(page_validate(btr_cur_get_page(&cur), ibuf.index));
-
-	if (page_is_empty(btr_cur_get_page(&cur))) {
-		/* If a B-tree page is empty, it must be the root page
-		and the whole B-tree must be empty. InnoDB does not
-		allow empty B-tree pages other than the root. */
-		ut_ad(ibuf.empty);
-		ut_ad(btr_cur_get_block(&cur)->page.id()
-		      == page_id_t(IBUF_SPACE_ID, FSP_IBUF_TREE_ROOT_PAGE_NO));
-
-		ibuf_mtr_commit(&mtr);
-
-		return(0);
-	}
-
-	ulint n_pages = 0;
-	sum_sizes = ibuf_get_merge_page_nos(TRUE,
-					    btr_cur_get_rec(&cur), &mtr,
-					    space_ids,
-					    page_nos, &n_pages);
-	ibuf_mtr_commit(&mtr);
-
-	ibuf_read_merge_pages(space_ids, page_nos, n_pages);
-
-	return(sum_sizes + 1);
-}
-
-/*********************************************************************//**
-Contracts insert buffer trees by reading pages referring to space_id
-to the buffer pool.
-@returns number of pages merged.*/
-ulint
-ibuf_merge_space(
-/*=============*/
-	ulint		space)	/*!< in: tablespace id to merge */
-{
-	mtr_t		mtr;
-	btr_pcur_t	pcur;
-
-	dfield_t dfield[IBUF_REC_FIELD_METADATA];
-	dtuple_t tuple {0, IBUF_REC_FIELD_METADATA,
-			IBUF_REC_FIELD_METADATA,dfield,0,nullptr
-#ifdef UNIV_DEBUG
-			, DATA_TUPLE_MAGIC_N
-#endif
-	};
-	byte space_id[4];
-
-	mach_write_to_4(space_id, space);
-
-	dfield_set_data(&dfield[0], space_id, 4);
-	dfield_set_data(&dfield[1], field_ref_zero, 1);
-	dfield_set_data(&dfield[2], field_ref_zero, 4);
-
-	dtuple_set_types_binary(&tuple, IBUF_REC_FIELD_METADATA);
-	ulint		n_pages = 0;
-
-	ut_ad(space < SRV_SPACE_ID_UPPER_BOUND);
-
-	log_free_check();
-	ibuf_mtr_start(&mtr);
-
-	/* Position the cursor on the first matching record. */
-
-	pcur.btr_cur.page_cur.index = ibuf.index;
-	dberr_t err = btr_pcur_open(&tuple, PAGE_CUR_GE,
-				    BTR_SEARCH_LEAF, &pcur, 0, &mtr);
-	ut_ad(err != DB_SUCCESS || page_validate(btr_pcur_get_page(&pcur),
-						 ibuf.index));
-
-	ulint		sum_sizes = 0;
-	uint32_t	pages[IBUF_MAX_N_PAGES_MERGED];
-	uint32_t	spaces[IBUF_MAX_N_PAGES_MERGED];
-
-	if (err != DB_SUCCESS) {
-	} else if (page_is_empty(btr_pcur_get_page(&pcur))) {
-		/* If a B-tree page is empty, it must be the root page
-		and the whole B-tree must be empty. InnoDB does not
-		allow empty B-tree pages other than the root. */
-		ut_ad(ibuf.empty);
-		ut_ad(btr_pcur_get_block(&pcur)->page.id()
-		      == page_id_t(IBUF_SPACE_ID, FSP_IBUF_TREE_ROOT_PAGE_NO));
-	} else {
-
-		sum_sizes = ibuf_get_merge_pages(
-			&pcur, uint32_t(space), IBUF_MAX_N_PAGES_MERGED,
-			&pages[0], &spaces[0], &n_pages,
-			&mtr);
-		ib::info() << "Size of pages merged " << sum_sizes;
-	}
-
-	ibuf_mtr_commit(&mtr);
-
-	if (n_pages > 0) {
-		ut_ad(n_pages <= UT_ARR_SIZE(pages));
-
-#ifdef UNIV_DEBUG
-		for (ulint i = 0; i < n_pages; ++i) {
-			ut_ad(spaces[i] == space);
-		}
-#endif /* UNIV_DEBUG */
-
-		ibuf_read_merge_pages(spaces, pages, n_pages);
-	}
-
-	return(n_pages);
-}
-
-/*********************************************************************//**
-Contract insert buffer trees after insert if they are too big. */
-UNIV_INLINE
-void
-ibuf_contract_after_insert(
-/*=======================*/
-	ulint	entry_size)	/*!< in: size of a record which was inserted
-				into an ibuf tree */
-{
-	/* dirty comparison, to avoid contention on ibuf_mutex */
-	if (ibuf.size < ibuf.max_size) {
-		return;
-	}
-
-	/* Contract at least entry_size many bytes */
-	ulint sum_sizes = 0;
-	ulint size;
-
-	do {
-		size = ibuf_contract();
-		sum_sizes += size;
-	} while (size > 0 && sum_sizes < entry_size);
-}
-
-/** Determine if a change buffer record has been encountered already.
-@param rec   change buffer record in the MySQL 5.5 format
-@param hash  hash table of encountered records
-@param size  number of elements in hash
-@retval true if a distinct record
-@retval false if this may be duplicating an earlier record */
-static bool ibuf_get_volume_buffered_hash(const rec_t *rec, ulint *hash,
-                                          ulint size)
-{
-  ut_ad(rec_get_n_fields_old(rec) > IBUF_REC_FIELD_USER);
-  const ulint start= rec_get_field_start_offs(rec, IBUF_REC_FIELD_USER);
-  const ulint len= rec_get_data_size_old(rec) - start;
-  const uint32_t fold= my_crc32c(0, rec + start, len);
-  hash+= (fold / (CHAR_BIT * sizeof *hash)) % size;
-  ulint bitmask= static_cast<ulint>(1) << (fold % (CHAR_BIT * sizeof(*hash)));
-
-  if (*hash & bitmask)
-    return false;
-
-  /* We have not seen this record yet. Remember it. */
-  *hash|= bitmask;
-  return true;
-}
-
-#ifdef UNIV_DEBUG
-# define ibuf_get_volume_buffered_count(mtr,rec,hash,size,n_recs)	\
-	ibuf_get_volume_buffered_count_func(mtr,rec,hash,size,n_recs)
-#else /* UNIV_DEBUG */
-# define ibuf_get_volume_buffered_count(mtr,rec,hash,size,n_recs)	\
-	ibuf_get_volume_buffered_count_func(rec,hash,size,n_recs)
-#endif /* UNIV_DEBUG */
-
-/*********************************************************************//**
-Update the estimate of the number of records on a page, and
-get the space taken by merging the buffered record to the index page.
-@return size of index record in bytes + an upper limit of the space
-taken in the page directory */
-static
-ulint
-ibuf_get_volume_buffered_count_func(
-/*================================*/
-#ifdef UNIV_DEBUG
-	mtr_t*		mtr,	/*!< in: mini-transaction owning rec */
-#endif /* UNIV_DEBUG */
-	const rec_t*	rec,	/*!< in: insert buffer record */
-	ulint*		hash,	/*!< in/out: hash array */
-	ulint		size,	/*!< in: number of elements in hash array */
-	lint*		n_recs)	/*!< in/out: estimated number of records
-				on the page that rec points to */
-{
-	ulint		len;
-	ibuf_op_t	ibuf_op;
-	const byte*	types;
-	ulint		n_fields;
-
-	ut_ad(mtr->memo_contains_page_flagged(rec, MTR_MEMO_PAGE_X_FIX
-					      | MTR_MEMO_PAGE_S_FIX));
-	ut_ad(ibuf_inside(mtr));
-
-	n_fields = rec_get_n_fields_old(rec);
-	ut_ad(n_fields > IBUF_REC_FIELD_USER);
-	n_fields -= IBUF_REC_FIELD_USER;
-
-	rec_get_nth_field_offs_old(rec, 1, &len);
-	/* This function is only invoked when buffering new
-	operations.  All pre-4.1 records should have been merged
-	when the database was started up. */
-	ut_a(len == 1);
-
-	if (rec_get_deleted_flag(rec, 0)) {
-		/* This record has been merged already,
-		but apparently the system crashed before
-		the change was discarded from the buffer.
-		Pretend that the record does not exist. */
-		return(0);
-	}
-
-	types = rec_get_nth_field_old(rec, IBUF_REC_FIELD_METADATA, &len);
-
-	switch (UNIV_EXPECT(int(len % DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE),
-			    IBUF_REC_INFO_SIZE)) {
-	default:
-		ut_error;
-	case 0:
-		/* This ROW_TYPE=REDUNDANT record does not include an
-		operation counter.  Exclude it from the *n_recs,
-		because deletes cannot be buffered if there are
-		old-style inserts buffered for the page. */
-
-		len = ibuf_rec_get_size(rec, types, n_fields, 0);
-
-		return(len
-		       + rec_get_converted_extra_size(len, n_fields, 0)
-		       + page_dir_calc_reserved_space(1));
-	case 1:
-		/* This ROW_TYPE=COMPACT record does not include an
-		operation counter.  Exclude it from the *n_recs,
-		because deletes cannot be buffered if there are
-		old-style inserts buffered for the page. */
-		goto get_volume_comp;
-
-	case IBUF_REC_INFO_SIZE:
-		ibuf_op = (ibuf_op_t) types[IBUF_REC_OFFSET_TYPE];
-		break;
-	}
-
-	switch (ibuf_op) {
-	case IBUF_OP_INSERT:
-		/* Inserts can be done by updating a delete-marked record.
-		Because delete-mark and insert operations can be pointing to
-		the same records, we must not count duplicates. */
-	case IBUF_OP_DELETE_MARK:
-		/* There must be a record to delete-mark.
-		See if this record has been already buffered. */
-		if (n_recs && ibuf_get_volume_buffered_hash(rec, hash, size)) {
-			(*n_recs)++;
-		}
-
-		if (ibuf_op == IBUF_OP_DELETE_MARK) {
-			/* Setting the delete-mark flag does not
-			affect the available space on the page. */
-			return(0);
-		}
-		break;
-	case IBUF_OP_DELETE:
-		/* A record will be removed from the page. */
-		if (n_recs) {
-			(*n_recs)--;
-		}
-		/* While deleting a record actually frees up space,
-		we have to play it safe and pretend that it takes no
-		additional space (the record might not exist, etc.). */
-		return(0);
-	default:
-		ut_error;
-	}
-
-	ut_ad(ibuf_op == IBUF_OP_INSERT);
-
-get_volume_comp:
-	{
-		dtuple_t*	entry;
-		ulint		volume;
-		dict_index_t*	dummy_index;
-		mem_heap_t*	heap = mem_heap_create(500);
-
-		entry = ibuf_build_entry_from_ibuf_rec(
-			mtr, rec, heap, &dummy_index);
-
-		volume = rec_get_converted_size(dummy_index, entry, 0);
-
-		ibuf_dummy_index_free(dummy_index);
-		mem_heap_free(heap);
-
-		return(volume + page_dir_calc_reserved_space(1));
-	}
-}
-
-/*********************************************************************//**
-Gets an upper limit for the combined size of entries buffered in the insert
-buffer for a given page.
-@return upper limit for the volume of buffered inserts for the index
-page, in bytes; srv_page_size, if the entries for the index page span
-several pages in the insert buffer */
-static
-ulint
-ibuf_get_volume_buffered(
-/*=====================*/
-	const btr_pcur_t*pcur,	/*!< in: pcur positioned at a place in an
-				insert buffer tree where we would insert an
-				entry for the index page whose number is
-				page_no, latch mode has to be BTR_MODIFY_PREV
-				or BTR_MODIFY_TREE */
-	ulint		space,	/*!< in: space id */
-	ulint		page_no,/*!< in: page number of an index page */
-	lint*		n_recs,	/*!< in/out: minimum number of records on the
-				page after the buffered changes have been
-				applied, or NULL to disable the counting */
-	mtr_t*		mtr)	/*!< in: mini-transaction of pcur */
-{
-	ulint		volume;
-	const rec_t*	rec;
-	const page_t*	page;
-	const page_t*	prev_page;
-	const page_t*	next_page;
-	/* bitmap of buffered recs */
-	ulint		hash_bitmap[128 / sizeof(ulint)];
-
-	ut_ad((pcur->latch_mode == BTR_MODIFY_PREV)
-	      || (pcur->latch_mode == BTR_MODIFY_TREE));
-
-	/* Count the volume of inserts earlier in the alphabetical order than
-	pcur */
-
-	volume = 0;
-
-	if (n_recs) {
-		memset(hash_bitmap, 0, sizeof hash_bitmap);
-	}
-
-	rec = btr_pcur_get_rec(pcur);
-	page = page_align(rec);
-	ut_ad(page_validate(page, ibuf.index));
-
-	if (page_rec_is_supremum(rec)
-	    && UNIV_UNLIKELY(!(rec = page_rec_get_prev_const(rec)))) {
-corruption:
-		ut_ad("corrupted page" == 0);
-		return srv_page_size;
-	}
-
-	uint32_t prev_page_no;
-
-	for (; !page_rec_is_infimum(rec); ) {
-		ut_ad(page_align(rec) == page);
-
-		if (page_no != ibuf_rec_get_page_no(mtr, rec)
-		    || space != ibuf_rec_get_space(mtr, rec)) {
-
-			goto count_later;
-		}
-
-		volume += ibuf_get_volume_buffered_count(
-			mtr, rec,
-			hash_bitmap, UT_ARR_SIZE(hash_bitmap), n_recs);
-
-		if (UNIV_UNLIKELY(!(rec = page_rec_get_prev_const(rec)))) {
-			goto corruption;
-		}
-	}
-
-	/* Look at the previous page */
-
-	prev_page_no = btr_page_get_prev(page);
-
-	if (prev_page_no == FIL_NULL) {
-
-		goto count_later;
-	}
-
-	if (buf_block_t* block =
-	    buf_page_get(page_id_t(IBUF_SPACE_ID, prev_page_no),
-			 0, RW_X_LATCH, mtr)) {
-		prev_page = buf_block_get_frame(block);
-		ut_ad(page_validate(prev_page, ibuf.index));
-	} else {
-		return srv_page_size;
-	}
-
-	static_assert(FIL_PAGE_NEXT % 4 == 0, "alignment");
-	static_assert(FIL_PAGE_OFFSET % 4 == 0, "alignment");
-
-	if (UNIV_UNLIKELY(memcmp_aligned<4>(prev_page + FIL_PAGE_NEXT,
-					    page + FIL_PAGE_OFFSET, 4))) {
-		return srv_page_size;
-	}
-
-	rec = page_rec_get_prev_const(page_get_supremum_rec(prev_page));
-
-	if (UNIV_UNLIKELY(!rec)) {
-		goto corruption;
-	}
-
-	for (;;) {
-		ut_ad(page_align(rec) == prev_page);
-
-		if (page_rec_is_infimum(rec)) {
-
-			/* We cannot go to yet a previous page, because we
-			do not have the x-latch on it, and cannot acquire one
-			because of the latching order: we have to give up */
-
-			return(srv_page_size);
-		}
-
-		if (page_no != ibuf_rec_get_page_no(mtr, rec)
-		    || space != ibuf_rec_get_space(mtr, rec)) {
-
-			goto count_later;
-		}
-
-		volume += ibuf_get_volume_buffered_count(
-			mtr, rec,
-			hash_bitmap, UT_ARR_SIZE(hash_bitmap), n_recs);
-
-		if (UNIV_UNLIKELY(!(rec = page_rec_get_prev_const(rec)))) {
-			goto corruption;
-		}
-	}
-
-count_later:
-	rec = btr_pcur_get_rec(pcur);
-
-	if (!page_rec_is_supremum(rec)) {
-		rec = page_rec_get_next_const(rec);
-	}
-
-	for (; !page_rec_is_supremum(rec);
-	     rec = page_rec_get_next_const(rec)) {
-		if (UNIV_UNLIKELY(!rec)) {
-			return srv_page_size;
-		}
-		if (page_no != ibuf_rec_get_page_no(mtr, rec)
-		    || space != ibuf_rec_get_space(mtr, rec)) {
-
-			return(volume);
-		}
-
-		volume += ibuf_get_volume_buffered_count(
-			mtr, rec,
-			hash_bitmap, UT_ARR_SIZE(hash_bitmap), n_recs);
-	}
-
-	/* Look at the next page */
-
-	uint32_t next_page_no = btr_page_get_next(page);
-
-	if (next_page_no == FIL_NULL) {
-
-		return(volume);
-	}
-
-	if (buf_block_t* block =
-	    buf_page_get(page_id_t(IBUF_SPACE_ID, next_page_no),
-			 0, RW_X_LATCH, mtr)) {
-		next_page = buf_block_get_frame(block);
-		ut_ad(page_validate(next_page, ibuf.index));
-	} else {
-		return srv_page_size;
-	}
-
-	static_assert(FIL_PAGE_PREV % 4 == 0, "alignment");
-	static_assert(FIL_PAGE_OFFSET % 4 == 0, "alignment");
-
-	if (UNIV_UNLIKELY(memcmp_aligned<4>(next_page + FIL_PAGE_PREV,
-					    page + FIL_PAGE_OFFSET, 4))) {
-		return 0;
-	}
-
-	rec = page_get_infimum_rec(next_page);
-	rec = page_rec_get_next_const(rec);
-
-	for (; ; rec = page_rec_get_next_const(rec)) {
-		if (!rec || page_rec_is_supremum(rec)) {
-			/* We give up */
-			return(srv_page_size);
-		}
-
-		ut_ad(page_align(rec) == next_page);
-
-		if (page_no != ibuf_rec_get_page_no(mtr, rec)
-		    || space != ibuf_rec_get_space(mtr, rec)) {
-
-			return(volume);
-		}
-
-		volume += ibuf_get_volume_buffered_count(
-			mtr, rec,
-			hash_bitmap, UT_ARR_SIZE(hash_bitmap), n_recs);
-	}
-}
-
-/*********************************************************************//**
-Reads the biggest tablespace id from the high end of the insert buffer
-tree and updates the counter in fil_system. */
-void
-ibuf_update_max_tablespace_id(void)
-/*===============================*/
-{
-	const rec_t*	rec;
-	const byte*	field;
-	ulint		len;
-	btr_pcur_t	pcur;
-	mtr_t		mtr;
-
-	ut_a(!dict_table_is_comp(ibuf.index->table));
-
-	ibuf_mtr_start(&mtr);
-
-	if (pcur.open_leaf(false, ibuf.index, BTR_SEARCH_LEAF, &mtr)
-	    != DB_SUCCESS) {
-func_exit:
-		ibuf_mtr_commit(&mtr);
-		return;
-	}
-
-	ut_ad(page_validate(btr_pcur_get_page(&pcur), ibuf.index));
-
-	if (!btr_pcur_move_to_prev(&pcur, &mtr)
-	    || btr_pcur_is_before_first_on_page(&pcur)) {
-		goto func_exit;
-	}
-
-	rec = btr_pcur_get_rec(&pcur);
-
-	field = rec_get_nth_field_old(rec, IBUF_REC_FIELD_SPACE, &len);
-
-	ut_a(len == 4);
-
-	const uint32_t max_space_id = mach_read_from_4(field);
-
-	ibuf_mtr_commit(&mtr);
-
-	/* printf("Maximum space id in insert buffer %lu\n", max_space_id); */
-
-	fil_set_max_space_id_if_bigger(max_space_id);
-}
-
-#ifdef UNIV_DEBUG
-# define ibuf_get_entry_counter_low(mtr,rec,space,page_no)	\
-	ibuf_get_entry_counter_low_func(mtr,rec,space,page_no)
-#else /* UNIV_DEBUG */
-# define ibuf_get_entry_counter_low(mtr,rec,space,page_no)	\
-	ibuf_get_entry_counter_low_func(rec,space,page_no)
-#endif
-/****************************************************************//**
-Helper function for ibuf_get_entry_counter_func. Checks if rec is for
-(space, page_no), and if so, reads counter value from it and returns
-that + 1.
-@retval ULINT_UNDEFINED if the record does not contain any counter
-@retval 0 if the record is not for (space, page_no)
-@retval 1 + previous counter value, otherwise */
-static
-ulint
-ibuf_get_entry_counter_low_func(
-/*============================*/
-#ifdef UNIV_DEBUG
-	mtr_t*		mtr,		/*!< in: mini-transaction of rec */
-#endif /* UNIV_DEBUG */
-	const rec_t*	rec,		/*!< in: insert buffer record */
-	ulint		space,		/*!< in: space id */
-	ulint		page_no)	/*!< in: page number */
-{
-	ulint		counter;
-	const byte*	field;
-	ulint		len;
-
-	ut_ad(ibuf_inside(mtr));
-	ut_ad(mtr->memo_contains_page_flagged(rec, MTR_MEMO_PAGE_X_FIX
-					      | MTR_MEMO_PAGE_S_FIX));
-	ut_ad(rec_get_n_fields_old(rec) > 2);
-
-	field = rec_get_nth_field_old(rec, IBUF_REC_FIELD_MARKER, &len);
-
-	ut_a(len == 1);
-
-	/* Check the tablespace identifier. */
-	field = rec_get_nth_field_old(rec, IBUF_REC_FIELD_SPACE, &len);
-
-	ut_a(len == 4);
-
-	if (mach_read_from_4(field) != space) {
-
-		return(0);
-	}
-
-	/* Check the page offset. */
-	field = rec_get_nth_field_old(rec, IBUF_REC_FIELD_PAGE, &len);
-	ut_a(len == 4);
-
-	if (mach_read_from_4(field) != page_no) {
-
-		return(0);
-	}
-
-	/* Check if the record contains a counter field. */
-	field = rec_get_nth_field_old(rec, IBUF_REC_FIELD_METADATA, &len);
-
-	switch (len % DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE) {
-	default:
-		ut_error;
-	case 0: /* ROW_FORMAT=REDUNDANT */
-	case 1: /* ROW_FORMAT=COMPACT */
-		return(ULINT_UNDEFINED);
-
-	case IBUF_REC_INFO_SIZE:
-		counter = mach_read_from_2(field + IBUF_REC_OFFSET_COUNTER);
-		ut_a(counter < 0xFFFF);
-		return(counter + 1);
-	}
-}
-
-#ifdef UNIV_DEBUG
-# define ibuf_get_entry_counter(space,page_no,rec,mtr,exact_leaf) \
-	ibuf_get_entry_counter_func(space,page_no,rec,mtr,exact_leaf)
-#else /* UNIV_DEBUG */
-# define ibuf_get_entry_counter(space,page_no,rec,mtr,exact_leaf) \
-	ibuf_get_entry_counter_func(space,page_no,rec,exact_leaf)
-#endif /* UNIV_DEBUG */
-
-/****************************************************************//**
-Calculate the counter field for an entry based on the current
-last record in ibuf for (space, page_no).
-@return the counter field, or ULINT_UNDEFINED
-if we should abort this insertion to ibuf */
-static
-ulint
-ibuf_get_entry_counter_func(
-/*========================*/
-	ulint		space,		/*!< in: space id of entry */
-	ulint		page_no,	/*!< in: page number of entry */
-	const rec_t*	rec,		/*!< in: the record preceding the
-					insertion point */
-#ifdef UNIV_DEBUG
-	mtr_t*		mtr,		/*!< in: mini-transaction */
-#endif /* UNIV_DEBUG */
-	ibool		only_leaf)	/*!< in: TRUE if this is the only
-					leaf page that can contain entries
-					for (space,page_no), that is, there
-					was no exact match for (space,page_no)
-					in the node pointer */
-{
-	ut_ad(ibuf_inside(mtr));
-	ut_ad(mtr->memo_contains_page_flagged(rec, MTR_MEMO_PAGE_X_FIX));
-	ut_ad(page_validate(page_align(rec), ibuf.index));
-
-	if (page_rec_is_supremum(rec)) {
-		/* This is just for safety. The record should be a
-		page infimum or a user record. */
-		ut_ad(0);
-		return(ULINT_UNDEFINED);
-	} else if (!page_rec_is_infimum(rec)) {
-		return(ibuf_get_entry_counter_low(mtr, rec, space, page_no));
-	} else if (only_leaf || !page_has_prev(page_align(rec))) {
-		/* The parent node pointer did not contain the
-		searched for (space, page_no), which means that the
-		search ended on the correct page regardless of the
-		counter value, and since we're at the infimum record,
-		there are no existing records. */
-		return(0);
-	} else {
-		/* We used to read the previous page here. It would
-		break the latching order, because the caller has
-		buffer-fixed an insert buffer bitmap page. */
-		return(ULINT_UNDEFINED);
-	}
-}
-
-
-/** Translates the ibuf free bits to the free space on a page in bytes.
-@param[in]	physical_size	page_size
-@param[in]	bits		value for ibuf bitmap bits
-@return maximum insert size after reorganize for the page */
-inline ulint
-ibuf_index_page_calc_free_from_bits(ulint physical_size, ulint bits)
-{
-	ut_ad(bits < 4);
-	ut_ad(physical_size > IBUF_PAGE_SIZE_PER_FREE_SPACE);
-
-	if (bits == 3) {
-		bits = 4;
-	}
-
-	return bits * physical_size / IBUF_PAGE_SIZE_PER_FREE_SPACE;
-}
-
-/** Buffer an operation in the insert/delete buffer, instead of doing it
-directly to the disk page, if this is possible.
-@param[in]	mode		BTR_MODIFY_PREV or BTR_INSERT_TREE
-@param[in]	op		operation type
-@param[in]	no_counter	TRUE=use 5.0.3 format; FALSE=allow delete
-buffering
-@param[in]	entry		index entry to insert
-@param[in]	entry_size	rec_get_converted_size(index, entry)
-@param[in,out]	index		index where to insert; must not be unique
-or clustered
-@param[in]	page_id		page id where to insert
-@param[in]	zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@param[in,out]	thr		query thread
-@return DB_SUCCESS, DB_STRONG_FAIL or other error */
-static TRANSACTIONAL_TARGET MY_ATTRIBUTE((warn_unused_result))
-dberr_t
-ibuf_insert_low(
-	btr_latch_mode		mode,
-	ibuf_op_t		op,
-	ibool			no_counter,
-	const dtuple_t*		entry,
-	ulint			entry_size,
-	dict_index_t*		index,
-	const page_id_t		page_id,
-	ulint			zip_size,
-	que_thr_t*		thr)
-{
-	big_rec_t*	dummy_big_rec;
-	btr_pcur_t	pcur;
-	btr_cur_t*	cursor;
-	dtuple_t*	ibuf_entry;
-	mem_heap_t*	offsets_heap	= NULL;
-	mem_heap_t*	heap;
-	rec_offs*	offsets		= NULL;
-	ulint		buffered;
-	lint		min_n_recs;
-	rec_t*		ins_rec;
-	buf_block_t*	bitmap_page;
-	buf_block_t*	block		= NULL;
-	page_t*		root;
-	dberr_t		err;
-	ibool		do_merge;
-	uint32_t	space_ids[IBUF_MAX_N_PAGES_MERGED];
-	uint32_t	page_nos[IBUF_MAX_N_PAGES_MERGED];
-	ulint		n_stored;
-	mtr_t		mtr;
-	mtr_t		bitmap_mtr;
-
-	ut_a(!dict_index_is_clust(index));
-	ut_ad(!dict_index_is_spatial(index));
-	ut_ad(dtuple_check_typed(entry));
-	ut_ad(!no_counter || op == IBUF_OP_INSERT);
-	ut_ad(page_id.space() == index->table->space_id);
-	ut_a(op < IBUF_OP_COUNT);
-
-	do_merge = FALSE;
-
-	/* Perform dirty comparison of ibuf.max_size and ibuf.size to
-	reduce ibuf_mutex contention. This should be OK; at worst we
-	are doing some excessive ibuf_contract() or occasionally
-	skipping an ibuf_contract(). */
-	const ulint max_size = ibuf.max_size;
-
-	if (max_size == 0) {
-		return(DB_STRONG_FAIL);
-	}
-
-	if (ibuf.size >= max_size + IBUF_CONTRACT_DO_NOT_INSERT) {
-		/* Insert buffer is now too big, contract it but do not try
-		to insert */
-
-
-#ifdef UNIV_IBUF_DEBUG
-		fputs("Ibuf too big\n", stderr);
-#endif
-		ibuf_contract();
-
-		return(DB_STRONG_FAIL);
-	}
-
-	heap = mem_heap_create(1024);
-
-	/* Build the entry which contains the space id and the page number
-	as the first fields and the type information for other fields, and
-	which will be inserted to the insert buffer. Using a counter value
-	of 0xFFFF we find the last record for (space, page_no), from which
-	we can then read the counter value N and use N + 1 in the record we
-	insert. (We patch the ibuf_entry's counter field to the correct
-	value just before actually inserting the entry.) */
-
-	ibuf_entry = ibuf_entry_build(
-		op, index, entry, page_id.space(), page_id.page_no(),
-		no_counter ? ULINT_UNDEFINED : 0xFFFF, heap);
-
-	/* Open a cursor to the insert buffer tree to calculate if we can add
-	the new entry to it without exceeding the free space limit for the
-	page. */
-
-	if (mode == BTR_INSERT_TREE) {
-		for (;;) {
-			mysql_mutex_lock(&ibuf_pessimistic_insert_mutex);
-			mysql_mutex_lock(&ibuf_mutex);
-
-			if (UNIV_LIKELY(ibuf_data_enough_free_for_insert())) {
-
-				break;
-			}
-
-			mysql_mutex_unlock(&ibuf_mutex);
-			mysql_mutex_unlock(&ibuf_pessimistic_insert_mutex);
-
-			if (!ibuf_add_free_page()) {
-
-				mem_heap_free(heap);
-				return(DB_STRONG_FAIL);
-			}
-		}
-	}
-
-	ibuf_mtr_start(&mtr);
-	pcur.btr_cur.page_cur.index = ibuf.index;
-
-	err = btr_pcur_open(ibuf_entry, PAGE_CUR_LE, mode, &pcur, 0, &mtr);
-	if (err != DB_SUCCESS) {
-func_exit:
-		ibuf_mtr_commit(&mtr);
-		ut_free(pcur.old_rec_buf);
-		mem_heap_free(heap);
-
-		if (err == DB_SUCCESS && mode == BTR_INSERT_TREE) {
-			ibuf_contract_after_insert(entry_size);
-		}
-
-		if (do_merge) {
-#ifdef UNIV_IBUF_DEBUG
-			ut_a(n_stored <= IBUF_MAX_N_PAGES_MERGED);
-#endif
-			ibuf_read_merge_pages(space_ids, page_nos, n_stored);
-		}
-		return err;
-	}
-
-	ut_ad(page_validate(btr_pcur_get_page(&pcur), ibuf.index));
-
-	/* Find out the volume of already buffered inserts for the same index
-	page */
-	min_n_recs = 0;
-	buffered = ibuf_get_volume_buffered(&pcur,
-					    page_id.space(),
-					    page_id.page_no(),
-					    op == IBUF_OP_DELETE
-					    ? &min_n_recs
-					    : NULL, &mtr);
-
-	const ulint physical_size = zip_size ? zip_size : srv_page_size;
-
-	if (op == IBUF_OP_DELETE
-	    && (min_n_recs < 2 || buf_pool.watch_occurred(page_id))) {
-		/* The page could become empty after the record is
-		deleted, or the page has been read in to the buffer
-		pool.  Refuse to buffer the operation. */
-
-		/* The buffer pool watch is needed for IBUF_OP_DELETE
-		because of latching order considerations.  We can
-		check buf_pool_watch_occurred() only after latching
-		the insert buffer B-tree pages that contain buffered
-		changes for the page.  We never buffer IBUF_OP_DELETE,
-		unless some IBUF_OP_INSERT or IBUF_OP_DELETE_MARK have
-		been previously buffered for the page.  Because there
-		are buffered operations for the page, the insert
-		buffer B-tree page latches held by mtr will guarantee
-		that no changes for the user page will be merged
-		before mtr_commit(&mtr).  We must not mtr_commit(&mtr)
-		until after the IBUF_OP_DELETE has been buffered. */
-
-fail_exit:
-		if (mode == BTR_INSERT_TREE) {
-			mysql_mutex_unlock(&ibuf_mutex);
-			mysql_mutex_unlock(&ibuf_pessimistic_insert_mutex);
-		}
-
-		err = DB_STRONG_FAIL;
-		goto func_exit;
-	}
-
-	/* After this point, the page could still be loaded to the
-	buffer pool, but we do not have to care about it, since we are
-	holding a latch on the insert buffer leaf page that contains
-	buffered changes for (space, page_no).  If the page enters the
-	buffer pool, buf_page_t::read_complete() for (space, page_no) will
-	have to acquire a latch on the same insert buffer leaf page,
-	which it cannot do until we have buffered the IBUF_OP_DELETE
-	and done mtr_commit(&mtr) to release the latch. */
-
-	ibuf_mtr_start(&bitmap_mtr);
-
-	bitmap_page = ibuf_bitmap_get_map_page(page_id, zip_size, &bitmap_mtr);
-
-	/* We check if the index page is suitable for buffered entries */
-
-	if (!bitmap_page || buf_pool.page_hash_contains(
-		    page_id, buf_pool.page_hash.cell_get(page_id.fold()))) {
-commit_exit:
-		ibuf_mtr_commit(&bitmap_mtr);
-		goto fail_exit;
-	} else if (!lock_sys.rd_lock_try()) {
-		goto commit_exit;
-	} else {
-		hash_cell_t* cell = lock_sys.rec_hash.cell_get(page_id.fold());
-		lock_sys.rec_hash.latch(cell)->acquire();
-		const lock_t* lock = lock_sys_t::get_first(*cell, page_id);
-		lock_sys.rec_hash.latch(cell)->release();
-		lock_sys.rd_unlock();
-		if (lock) {
-			goto commit_exit;
-		}
-	}
-
-	if (op == IBUF_OP_INSERT) {
-		ulint	bits = ibuf_bitmap_page_get_bits(
-			bitmap_page->page.frame, page_id, physical_size,
-			IBUF_BITMAP_FREE, &bitmap_mtr);
-
-		if (buffered + entry_size + page_dir_calc_reserved_space(1)
-		    > ibuf_index_page_calc_free_from_bits(physical_size,
-							  bits)) {
-			/* Release the bitmap page latch early. */
-			ibuf_mtr_commit(&bitmap_mtr);
-
-			/* It may not fit */
-			do_merge = TRUE;
-
-			ibuf_get_merge_page_nos(FALSE,
-						btr_pcur_get_rec(&pcur), &mtr,
-						space_ids,
-						page_nos, &n_stored);
-
-			goto fail_exit;
-		}
-	}
-
-	if (!no_counter) {
-		/* Patch correct counter value to the entry to
-		insert. This can change the insert position, which can
-		result in the need to abort in some cases. */
-		ulint		counter = ibuf_get_entry_counter(
-			page_id.space(), page_id.page_no(),
-			btr_pcur_get_rec(&pcur), &mtr,
-			btr_pcur_get_btr_cur(&pcur)->low_match
-			< IBUF_REC_FIELD_METADATA);
-		dfield_t*	field;
-
-		if (counter == ULINT_UNDEFINED) {
-			goto commit_exit;
-		}
-
-		field = dtuple_get_nth_field(
-			ibuf_entry, IBUF_REC_FIELD_METADATA);
-		mach_write_to_2(
-			(byte*) dfield_get_data(field)
-			+ IBUF_REC_OFFSET_COUNTER, counter);
-	}
-
-	/* Set the bitmap bit denoting that the insert buffer contains
-	buffered entries for this index page, if the bit is not set yet */
-	index->set_modified(bitmap_mtr);
-	ibuf_bitmap_page_set_bits<IBUF_BITMAP_BUFFERED>(
-		bitmap_page, page_id, physical_size, true, &bitmap_mtr);
-	ibuf_mtr_commit(&bitmap_mtr);
-
-	cursor = btr_pcur_get_btr_cur(&pcur);
-
-	if (mode == BTR_MODIFY_PREV) {
-		err = btr_cur_optimistic_insert(
-			BTR_NO_LOCKING_FLAG | BTR_NO_UNDO_LOG_FLAG,
-			cursor, &offsets, &offsets_heap,
-			ibuf_entry, &ins_rec,
-			&dummy_big_rec, 0, thr, &mtr);
-		block = btr_cur_get_block(cursor);
-		ut_ad(block->page.id().space() == IBUF_SPACE_ID);
-
-		/* If this is the root page, update ibuf.empty. */
-		if (block->page.id().page_no() == FSP_IBUF_TREE_ROOT_PAGE_NO) {
-			const page_t*	root = buf_block_get_frame(block);
-
-			ut_ad(page_get_space_id(root) == IBUF_SPACE_ID);
-			ut_ad(page_get_page_no(root)
-			      == FSP_IBUF_TREE_ROOT_PAGE_NO);
-
-			ibuf.empty = page_is_empty(root);
-		}
-	} else {
-		ut_ad(mode == BTR_INSERT_TREE);
-
-		/* We acquire an sx-latch to the root page before the insert,
-		because a pessimistic insert releases the tree x-latch,
-		which would cause the sx-latching of the root after that to
-		break the latching order. */
-		if (buf_block_t* ibuf_root = ibuf_tree_root_get(&mtr)) {
-			root = ibuf_root->page.frame;
-		} else {
-			err = DB_CORRUPTION;
-			mysql_mutex_unlock(&ibuf_pessimistic_insert_mutex);
-			mysql_mutex_unlock(&ibuf_mutex);
-			goto ibuf_insert_done;
-		}
-
-		err = btr_cur_optimistic_insert(
-			BTR_NO_LOCKING_FLAG | BTR_NO_UNDO_LOG_FLAG,
-			cursor, &offsets, &offsets_heap,
-			ibuf_entry, &ins_rec,
-			&dummy_big_rec, 0, thr, &mtr);
-
-		if (err == DB_FAIL) {
-			err = btr_cur_pessimistic_insert(
-				BTR_NO_LOCKING_FLAG | BTR_NO_UNDO_LOG_FLAG,
-				cursor, &offsets, &offsets_heap,
-				ibuf_entry, &ins_rec,
-				&dummy_big_rec, 0, thr, &mtr);
-		}
-
-		mysql_mutex_unlock(&ibuf_pessimistic_insert_mutex);
-		ibuf_size_update(root);
-		mysql_mutex_unlock(&ibuf_mutex);
-		ibuf.empty = page_is_empty(root);
-
-		block = btr_cur_get_block(cursor);
-		ut_ad(block->page.id().space() == IBUF_SPACE_ID);
-	}
-
-ibuf_insert_done:
-	if (offsets_heap) {
-		mem_heap_free(offsets_heap);
-	}
-
-	if (err == DB_SUCCESS && op != IBUF_OP_DELETE) {
-		/* Update the page max trx id field */
-		page_update_max_trx_id(block, NULL,
-				       thr_get_trx(thr)->id, &mtr);
-	}
-
-	goto func_exit;
-}
-
-/** Buffer an operation in the change buffer, instead of applying it
-directly to the file page, if this is possible. Does not do it if the index
-is clustered or unique.
-@param[in]	op		operation type
-@param[in]	entry		index entry to insert
-@param[in,out]	index		index where to insert
-@param[in]	page_id		page id where to insert
-@param[in]	zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@param[in,out]	thr		query thread
-@return true if success */
-TRANSACTIONAL_TARGET
-bool
-ibuf_insert(
-	ibuf_op_t		op,
-	const dtuple_t*		entry,
-	dict_index_t*		index,
-	const page_id_t		page_id,
-	ulint			zip_size,
-	que_thr_t*		thr)
-{
-	dberr_t		err;
-	ulint		entry_size;
-	ibool		no_counter;
-	/* Read the settable global variable only once in
-	this function, so that we will have a consistent view of it. */
-	ibuf_use_t	use		= ibuf_use_t(innodb_change_buffering);
-	DBUG_ENTER("ibuf_insert");
-
-	DBUG_PRINT("ibuf", ("op: %d, space: " UINT32PF ", page_no: " UINT32PF,
-			    op, page_id.space(), page_id.page_no()));
-
-	ut_ad(dtuple_check_typed(entry));
-	ut_ad(page_id.space() != SRV_TMP_SPACE_ID);
-	ut_ad(index->is_btree());
-	ut_a(!dict_index_is_clust(index));
-	ut_ad(!index->table->is_temporary());
-
-	no_counter = use <= IBUF_USE_INSERT;
-
-	switch (op) {
-	case IBUF_OP_INSERT:
-		switch (use) {
-		case IBUF_USE_NONE:
-		case IBUF_USE_DELETE:
-		case IBUF_USE_DELETE_MARK:
-			DBUG_RETURN(false);
-		case IBUF_USE_INSERT:
-		case IBUF_USE_INSERT_DELETE_MARK:
-		case IBUF_USE_ALL:
-			goto check_watch;
-		}
-		break;
-	case IBUF_OP_DELETE_MARK:
-		switch (use) {
-		case IBUF_USE_NONE:
-		case IBUF_USE_INSERT:
-			DBUG_RETURN(false);
-		case IBUF_USE_DELETE_MARK:
-		case IBUF_USE_DELETE:
-		case IBUF_USE_INSERT_DELETE_MARK:
-		case IBUF_USE_ALL:
-			ut_ad(!no_counter);
-			goto check_watch;
-		}
-		break;
-	case IBUF_OP_DELETE:
-		switch (use) {
-		case IBUF_USE_NONE:
-		case IBUF_USE_INSERT:
-		case IBUF_USE_INSERT_DELETE_MARK:
-			DBUG_RETURN(false);
-		case IBUF_USE_DELETE_MARK:
-		case IBUF_USE_DELETE:
-		case IBUF_USE_ALL:
-			ut_ad(!no_counter);
-			goto skip_watch;
-		}
-		break;
-	case IBUF_OP_COUNT:
-		break;
-	}
 
-	/* unknown op or use */
-	ut_error;
-
-check_watch:
-	/* If a thread attempts to buffer an insert on a page while a
-	purge is in progress on the same page, the purge must not be
-	buffered, because it could remove a record that was
-	re-inserted later.  For simplicity, we block the buffering of
-	all operations on a page that has a purge pending.
-
-	We do not check this in the IBUF_OP_DELETE case, because that
-	would always trigger the buffer pool watch during purge and
-	thus prevent the buffering of delete operations.  We assume
-	that the issuer of IBUF_OP_DELETE has called
-	buf_pool_t::watch_set(). */
-
-	if (buf_pool.page_hash_contains<true>(
-		    page_id, buf_pool.page_hash.cell_get(page_id.fold()))) {
-		/* A buffer pool watch has been set or the
-		page has been read into the buffer pool.
-		Do not buffer the request.  If a purge operation
-		is being buffered, have this request executed
-		directly on the page in the buffer pool after the
-		buffered entries for this page have been merged. */
-		DBUG_RETURN(false);
-	}
+  /* Since pessimistic inserts were prevented, we know that the
+  page is still in the free list. NOTE that also deletes may take
+  pages from the free list, but they take them from the start, and
+  the free list was so long that they cannot have taken the last
+  page from it. */
 
-skip_watch:
-	entry_size = rec_get_converted_size(index, entry, 0);
+  err= fseg_free_page(header->page.frame + PAGE_DATA, fil_system.sys_space,
+                      page_no, &mtr);
 
-	if (entry_size
-	    >= page_get_free_space_of_empty(dict_table_is_comp(index->table))
-	    / 2) {
+  if (err != DB_SUCCESS)
+    goto func_exit;
 
-		DBUG_RETURN(false);
-	}
+  if (page_no != flst_get_last(PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST +
+                               root->page.frame).page)
+  {
+    err= DB_CORRUPTION;
+    goto func_exit;
+  }
 
-	err = ibuf_insert_low(BTR_MODIFY_PREV, op, no_counter,
-			      entry, entry_size,
-			      index, page_id, zip_size, thr);
-	if (err == DB_FAIL) {
-		err = ibuf_insert_low(BTR_INSERT_TREE,
-				      op, no_counter, entry, entry_size,
-				      index, page_id, zip_size, thr);
-	}
+  /* Remove the page from the free list and update the ibuf size data */
+  if (buf_block_t *block=
+      buf_page_get_gen(page_id_t{0, page_no}, 0, RW_X_LATCH, nullptr, BUF_GET,
+                       &mtr, &err))
+    err= flst_remove(root, PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST,
+                     block, PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST_NODE, &mtr);
 
-	ut_a(err == DB_SUCCESS || err == DB_STRONG_FAIL
-	     || err == DB_TOO_BIG_RECORD);
+  if (err == DB_SUCCESS)
+    buf_page_free(fil_system.sys_space, page_no, &mtr);
 
-	DBUG_RETURN(err == DB_SUCCESS);
+  goto func_exit;
 }
 
 MY_ATTRIBUTE((nonnull, warn_unused_result))
@@ -3616,9 +316,7 @@ ibuf_insert_to_index_page_low(
     return DB_SUCCESS;
 
   /* Page reorganization or recompression should already have been
-  attempted by page_cur_tuple_insert(). Besides, per
-  ibuf_index_page_calc_free_zip() the page should not have been
-  recompressed or reorganized. */
+  attempted by page_cur_tuple_insert(). */
   ut_ad(!is_buf_block_get_page_zip(page_cur->block));
 
   /* If the record did not fit, reorganize */
@@ -3656,19 +354,16 @@ ibuf_insert_to_index_page(
 			    block->page.id().page_no()));
 
 	ut_ad(!dict_index_is_online_ddl(index));// this is an ibuf_dummy index
-	ut_ad(ibuf_inside(mtr));
 	ut_ad(dtuple_check_typed(entry));
 #ifdef BTR_CUR_HASH_ADAPT
-	/* A change buffer merge must occur before users are granted
-	any access to the page. No adaptive hash index entries may
-	point to a freshly read page. */
+	/* ibuf_cleanup() must finish before the adaptive hash index
+	can be inserted into. */
 	ut_ad(!block->index);
-	assert_block_ahi_empty(block);
 #endif /* BTR_CUR_HASH_ADAPT */
 	ut_ad(mtr->is_named_space(block->page.id().space()));
 
-	if (UNIV_UNLIKELY(dict_table_is_comp(index->table)
-			  != (ibool)!!page_is_comp(page))) {
+	if (UNIV_UNLIKELY(index->table->not_redundant()
+			  != !!page_is_comp(page))) {
 		return DB_CORRUPTION;
 	}
 
@@ -3808,7 +503,6 @@ ibuf_set_del_mark(
 	page_cur.index = index;
 	ulint		up_match = 0, low_match = 0;
 
-	ut_ad(ibuf_inside(mtr));
 	ut_ad(dtuple_check_typed(entry));
 
 	if (!page_cur_search_with_match(entry, PAGE_CUR_LE,
@@ -3867,7 +561,6 @@ ibuf_delete(
 	page_cur.index = index;
 	ulint		up_match = 0, low_match = 0;
 
-	ut_ad(ibuf_inside(mtr));
 	ut_ad(dtuple_check_typed(entry));
 	ut_ad(!index->is_spatial());
 	ut_ad(!index->is_clust());
@@ -3876,7 +569,6 @@ ibuf_delete(
 					&up_match, &low_match, &page_cur,
 					nullptr)
 	    && low_match == dtuple_get_n_fields(entry)) {
-		page_zip_des_t*	page_zip= buf_block_get_page_zip(block);
 		page_t*		page	= buf_block_get_frame(block);
 		rec_t*		rec	= page_cur_get_rec(&page_cur);
 
@@ -3886,7 +578,6 @@ ibuf_delete(
 		rec_offs	offsets_[REC_OFFS_NORMAL_SIZE];
 		rec_offs*	offsets	= offsets_;
 		mem_heap_t*	heap = NULL;
-		ulint		max_ins_size = 0;
 
 		rec_offs_init(offsets_);
 
@@ -3917,12 +608,8 @@ ibuf_delete(
 			return;
 		}
 
-		if (!page_zip) {
-			max_ins_size
-				= page_get_max_insert_size_after_reorganize(
-					page, 1);
-		}
 #ifdef UNIV_ZIP_DEBUG
+		page_zip_des_t*	page_zip= buf_block_get_page_zip(block);
 		ut_a(!page_zip || page_zip_validate(page_zip, page, index));
 #endif /* UNIV_ZIP_DEBUG */
 		page_cur_delete_rec(&page_cur, offsets, mtr);
@@ -3930,774 +617,370 @@ ibuf_delete(
 		ut_a(!page_zip || page_zip_validate(page_zip, page, index));
 #endif /* UNIV_ZIP_DEBUG */
 
-		if (page_zip) {
-			ibuf_update_free_bits_zip(block, mtr);
-		} else {
-			ibuf_update_free_bits_low(block, max_ins_size, mtr);
-		}
-
 		if (UNIV_LIKELY_NULL(heap)) {
 			mem_heap_free(heap);
 		}
 	}
 }
 
-/*********************************************************************//**
-Restores insert buffer tree cursor position
-@return whether the position was restored */
-static MY_ATTRIBUTE((nonnull))
-bool
-ibuf_restore_pos(
-/*=============*/
-	const page_id_t	page_id,/*!< in: page identifier */
-	const dtuple_t*	search_tuple,
-				/*!< in: search tuple for entries of page_no */
-	btr_latch_mode	mode,	/*!< in: BTR_MODIFY_LEAF or BTR_PURGE_TREE */
-	btr_pcur_t*	pcur,	/*!< in/out: persistent cursor whose
-				position is to be restored */
-	mtr_t*		mtr)	/*!< in/out: mini-transaction */
+/** Reset the bits in the bitmap page for the given page number.
+@param bitmap   change buffer bitmap page
+@param offset   page number
+@param mtr      mini-transaction */
+static void ibuf_reset(buf_block_t &bitmap, uint32_t offset, mtr_t *mtr)
 {
-	ut_ad(mode == BTR_MODIFY_LEAF || mode == BTR_PURGE_TREE);
-
-	if (UNIV_LIKELY(pcur->restore_position(mode, mtr) ==
-	      btr_pcur_t::SAME_ALL)) {
-		return true;
-	}
-
-	if (fil_space_t* s = fil_space_t::get(page_id.space())) {
-		ib::error() << "ibuf cursor restoration fails!"
-			" ibuf record inserted to page "
-			<< page_id
-			<< " in file " << s->chain.start->name;
-		s->release();
-
-		ib::error() << BUG_REPORT_MSG;
-
-		rec_print_old(stderr, btr_pcur_get_rec(pcur));
-		rec_print_old(stderr, pcur->old_rec);
-		dtuple_print(stderr, search_tuple);
-	}
-
-	ibuf_btr_pcur_commit_specify_mtr(pcur, mtr);
-	return false;
+  offset&= uint32_t(bitmap.physical_size() - 1);
+  byte *map_byte= &bitmap.page.frame[PAGE_DATA + offset / 2];
+  /* We must reset IBUF_BITMAP_BUFFERED, but at the same time we will also
+  reset IBUF_BITMAP_FREE (and IBUF_BITMAP_IBUF, which should be clear). */
+  byte b= byte(*map_byte & ((offset & 1) ? byte{0xf} : byte{0xf0}));
+  mtr->write<1,mtr_t::MAYBE_NOP>(bitmap, map_byte, b);
 }
 
-/**
-Delete a change buffer record.
-@param[in]	page_id		page identifier
-@param[in,out]	pcur		persistent cursor positioned on the record
-@param[in]	search_tuple	search key for (space,page_no)
-@param[in,out]	mtr		mini-transaction
-@return whether mtr was committed (due to pessimistic operation) */
-static MY_ATTRIBUTE((warn_unused_result, nonnull))
-bool ibuf_delete_rec(const page_id_t page_id, btr_pcur_t* pcur,
-		     const dtuple_t* search_tuple, mtr_t* mtr)
+/** Move to the next change buffer record. */
+ATTRIBUTE_COLD static dberr_t ibuf_move_to_next(btr_cur_t *cur, mtr_t *mtr)
 {
-	dberr_t		err;
-
-	ut_ad(ibuf_inside(mtr));
-	ut_ad(page_rec_is_user_rec(btr_pcur_get_rec(pcur)));
-	ut_ad(ibuf_rec_get_page_no(mtr, btr_pcur_get_rec(pcur))
-	      == page_id.page_no());
-	ut_ad(ibuf_rec_get_space(mtr, btr_pcur_get_rec(pcur))
-	      == page_id.space());
-
-	switch (btr_cur_optimistic_delete(btr_pcur_get_btr_cur(pcur),
-					  BTR_CREATE_FLAG, mtr)) {
-	case DB_FAIL:
-		break;
-	case DB_SUCCESS:
-		if (page_is_empty(btr_pcur_get_page(pcur))) {
-			/* If a B-tree page is empty, it must be the root page
-			and the whole B-tree must be empty. InnoDB does not
-			allow empty B-tree pages other than the root. */
-			ut_d(const page_t* root = btr_pcur_get_page(pcur));
-
-			ut_ad(page_get_space_id(root) == IBUF_SPACE_ID);
-			ut_ad(page_get_page_no(root)
-			      == FSP_IBUF_TREE_ROOT_PAGE_NO);
-
-			/* ibuf.empty is protected by the root page latch.
-			Before the deletion, it had to be FALSE. */
-			ut_ad(!ibuf.empty);
-			ibuf.empty = true;
-		}
-		/* fall through */
-	default:
-		return(FALSE);
-	}
-
-	/* We have to resort to a pessimistic delete from ibuf.
-	Delete-mark the record so that it will not be applied again,
-	in case the server crashes before the pessimistic delete is
-	made persistent. */
-	btr_rec_set_deleted<true>(btr_pcur_get_block(pcur),
-				  btr_pcur_get_rec(pcur), mtr);
-
-	btr_pcur_store_position(pcur, mtr);
-	ibuf_btr_pcur_commit_specify_mtr(pcur, mtr);
-
-	ibuf_mtr_start(mtr);
-	mysql_mutex_lock(&ibuf_mutex);
-
-	if (!ibuf_restore_pos(page_id, search_tuple, BTR_PURGE_TREE,
-			      pcur, mtr)) {
-
-		mysql_mutex_unlock(&ibuf_mutex);
-		ut_ad(mtr->has_committed());
-		goto func_exit;
-	}
-
-	if (buf_block_t* ibuf_root = ibuf_tree_root_get(mtr)) {
-		btr_cur_pessimistic_delete(&err, TRUE,
-					   btr_pcur_get_btr_cur(pcur),
-					   BTR_CREATE_FLAG, false, mtr);
-		ut_a(err == DB_SUCCESS);
-
-		ibuf_size_update(ibuf_root->page.frame);
-		mysql_mutex_unlock(&ibuf_mutex);
-
-		ibuf.empty = page_is_empty(ibuf_root->page.frame);
-	} else {
-		mysql_mutex_unlock(&ibuf_mutex);
-	}
-
-	ibuf_btr_pcur_commit_specify_mtr(pcur, mtr);
-
-func_exit:
-	ut_ad(mtr->has_committed());
-	btr_pcur_close(pcur);
-
-	return(TRUE);
-}
+  if (!page_cur_move_to_next(&cur->page_cur))
+    return DB_CORRUPTION;
+  if (!page_cur_is_after_last(&cur->page_cur))
+    return DB_SUCCESS;
 
-/** Check whether buffered changes exist for a page.
-@param[in]	id		page identifier
-@param[in]	zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@return whether buffered changes exist */
-bool ibuf_page_exists(const page_id_t id, ulint zip_size)
-{
-	ut_ad(!fsp_is_system_temporary(id.space()));
+  /* The following is adapted from btr_pcur_move_to_next_page(),
+  but we will not release any latches. */
 
-	const ulint physical_size = zip_size ? zip_size : srv_page_size;
+  const buf_block_t &block= *cur->page_cur.block;
+  const uint32_t next_page_no= btr_page_get_next(block.page.frame);
+  switch (next_page_no) {
+  case 0:
+  case 1:
+    return DB_CORRUPTION;
+  case FIL_NULL:
+    return DB_SUCCESS;
+  }
 
-	if (ibuf_fixed_addr_page(id, physical_size)
-	    || fsp_descr_page(id, physical_size)) {
-		return false;
-	}
+  if (UNIV_UNLIKELY(next_page_no == block.page.id().page_no()))
+    return DB_CORRUPTION;
 
-	mtr_t mtr;
-	bool bitmap_bits = false;
+  dberr_t err;
+  buf_block_t *next=
+    btr_block_get(*cur->index(), next_page_no, BTR_MODIFY_LEAF, mtr, &err);
+  if (!next)
+    return err;
 
-	ibuf_mtr_start(&mtr);
-	if (const buf_block_t* bitmap_page = ibuf_bitmap_get_map_page(
-		    id, zip_size, &mtr)) {
-		bitmap_bits = ibuf_bitmap_page_get_bits(
-			bitmap_page->page.frame, id, zip_size,
-			IBUF_BITMAP_BUFFERED, &mtr) != 0;
-	}
-	ibuf_mtr_commit(&mtr);
-	return bitmap_bits;
-}
+  if (UNIV_UNLIKELY(memcmp_aligned<4>(next->page.frame + FIL_PAGE_PREV,
+                                      block.page.frame + FIL_PAGE_OFFSET, 4)))
+    return DB_CORRUPTION;
 
-/** Reset the bits in the bitmap page for the given block and page id.
-@param b        X-latched secondary index page (nullptr to discard changes)
-@param page_id  page identifier
-@param zip_size ROW_FORMAT=COMPRESSED page size, or 0
-@param mtr      mini-transaction */
-static void ibuf_reset_bitmap(buf_block_t *b, page_id_t page_id,
-                              ulint zip_size, mtr_t *mtr)
-{
- buf_block_t *bitmap= ibuf_bitmap_get_map_page(page_id, zip_size, mtr);
- if (!bitmap)
-   return;
-
- const ulint physical_size = zip_size ? zip_size : srv_page_size;
- /* FIXME: update the bitmap byte only once! */
- ibuf_bitmap_page_set_bits<IBUF_BITMAP_BUFFERED>(bitmap, page_id,
-                                                 physical_size, false, mtr);
-
- if (b)
-   ibuf_bitmap_page_set_bits<IBUF_BITMAP_FREE>(bitmap, page_id, physical_size,
-                                               ibuf_index_page_calc_free(b),
-                                               mtr);
+  page_cur_set_before_first(next, &cur->page_cur);
+  return page_cur_move_to_next(&cur->page_cur) ? DB_SUCCESS : DB_CORRUPTION;
 }
 
-/** When an index page is read from a disk to the buffer pool, this function
-applies any buffered operations to the page and deletes the entries from the
-insert buffer. If the page is not read, but created in the buffer pool, this
-function deletes its buffered entries from the insert buffer; there can
-exist entries for such a page if the page belonged to an index which
-subsequently was dropped.
-@param block    X-latched page to try to apply changes to, or NULL to discard
-@param page_id  page identifier
-@param zip_size ROW_FORMAT=COMPRESSED page size, or 0
-@return error code */
-dberr_t ibuf_merge_or_delete_for_page(buf_block_t *block,
-                                      const page_id_t page_id,
-                                      ulint zip_size)
+/** Apply changes to a block. */
+ATTRIBUTE_COLD
+static dberr_t ibuf_merge(fil_space_t *space, btr_cur_t *cur, mtr_t *mtr)
 {
-	if (trx_sys_hdr_page(page_id)) {
-		return DB_SUCCESS;
-	}
-
-	ut_ad(!block || page_id == block->page.id());
-	ut_ad(!block || block->page.frame);
-	ut_ad(!block || !block->page.is_ibuf_exist());
-	ut_ad(!block || !block->page.is_reinit());
-	ut_ad(!trx_sys_hdr_page(page_id));
-	ut_ad(page_id < page_id_t(SRV_SPACE_ID_UPPER_BOUND, 0));
-
-	const ulint physical_size = zip_size ? zip_size : srv_page_size;
-
-	if (ibuf_fixed_addr_page(page_id, physical_size)
-	    || fsp_descr_page(page_id, physical_size)) {
-		return DB_SUCCESS;
-	}
-
-	btr_pcur_t	pcur;
-#ifdef UNIV_IBUF_DEBUG
-	ulint		volume			= 0;
-#endif /* UNIV_IBUF_DEBUG */
-	dberr_t		err = DB_SUCCESS;
-	mtr_t		mtr;
-
-	fil_space_t* space = fil_space_t::get(page_id.space());
-
-	if (UNIV_UNLIKELY(!space)) {
-		block = nullptr;
-	} else {
-		ulint	bitmap_bits = 0;
-
-		ibuf_mtr_start(&mtr);
-
-		buf_block_t* bitmap_page = ibuf_bitmap_get_map_page(
-			page_id, zip_size, &mtr);
-
-		if (bitmap_page
-		    && fil_page_get_type(bitmap_page->page.frame)
-		    != FIL_PAGE_TYPE_ALLOCATED) {
-			bitmap_bits = ibuf_bitmap_page_get_bits(
-				bitmap_page->page.frame, page_id, zip_size,
-				IBUF_BITMAP_BUFFERED, &mtr);
-		}
-
-		ibuf_mtr_commit(&mtr);
-
-		if (bitmap_bits
-		    && DB_SUCCESS
-		    == fseg_page_is_allocated(space, page_id.page_no())) {
-			ibuf_mtr_start(&mtr);
-			mtr.set_named_space(space);
-			ibuf_reset_bitmap(block, page_id, zip_size, &mtr);
-			ibuf_mtr_commit(&mtr);
-			bitmap_bits = 0;
-			if (!block
-			    || btr_page_get_index_id(block->page.frame)
-			    != DICT_IBUF_ID_MIN + IBUF_SPACE_ID) {
-				ibuf_delete_recs(page_id);
-			}
-		}
-
-		if (!bitmap_bits) {
-			/* No changes are buffered for this page. */
-			space->release();
-			return DB_SUCCESS;
-		}
-	}
+  if (btr_cur_get_rec(cur)[4])
+    return DB_CORRUPTION;
 
-	if (!block) {
-	} else if (!fil_page_index_page_check(block->page.frame)
-		   || !page_is_leaf(block->page.frame)) {
-		space->set_corrupted();
-		err = DB_CORRUPTION;
-		block = nullptr;
-	} else {
-		/* Move the ownership of the x-latch on the page to this OS
-		thread, so that we can acquire a second x-latch on it. This
-		is needed for the insert operations to the index page to pass
-		the debug checks. */
-
-		block->page.lock.claim_ownership();
-	}
-
-	mem_heap_t* heap = mem_heap_create(512);
-
-	const dtuple_t* search_tuple = ibuf_search_tuple_build(
-		page_id.space(), page_id.page_no(), heap);
-
-	/* Counts for merged & discarded operations. */
-	ulint mops[IBUF_OP_COUNT];
-	ulint dops[IBUF_OP_COUNT];
-
-	memset(mops, 0, sizeof(mops));
-	memset(dops, 0, sizeof(dops));
-	pcur.btr_cur.page_cur.index = ibuf.index;
-
-loop:
-	ibuf_mtr_start(&mtr);
+  const uint32_t space_id= mach_read_from_4(btr_cur_get_rec(cur));
+  const uint32_t page_no= mach_read_from_4(btr_cur_get_rec(cur) + 5);
 
-	/* Position pcur in the insert buffer at the first entry for this
-	index page */
-	if (btr_pcur_open_on_user_rec(search_tuple, PAGE_CUR_GE,
-				      BTR_MODIFY_LEAF, &pcur, &mtr)
-	    != DB_SUCCESS) {
-		err = DB_CORRUPTION;
-		goto reset_bit;
-	}
-
-	if (block) {
-		block->page.fix();
-		block->page.lock.x_lock_recursive();
-		mtr.memo_push(block, MTR_MEMO_PAGE_X_FIX);
-	}
-
-	if (space) {
-		mtr.set_named_space(space);
-	}
+  buf_block_t *block= space && page_no < space->size
+    ? buf_page_get_gen(page_id_t{space_id, page_no}, space->zip_size(),
+                       RW_X_LATCH, nullptr, BUF_GET_POSSIBLY_FREED, mtr)
+    : nullptr;
 
-	if (!btr_pcur_is_on_user_rec(&pcur)) {
-		ut_ad(btr_pcur_is_after_last_on_page(&pcur));
-		goto reset_bit;
-	}
+  buf_block_t *bitmap= block
+    ? buf_page_get_gen(page_id_t(space_id,
+                                 uint32_t(page_no &
+                                          ~(block->physical_size() - 1)) + 1),
+                       block->zip_size(), RW_X_LATCH, nullptr,
+                       BUF_GET_POSSIBLY_FREED, mtr)
+    : nullptr;
 
-	for (;;) {
-		rec_t*	rec;
+  if (!block);
+  else if (fil_page_get_type(block->page.frame) != FIL_PAGE_INDEX ||
+           !page_is_leaf(block->page.frame) ||
+           DB_SUCCESS == fseg_page_is_allocated(space, page_no))
+    block= nullptr;
 
-		ut_ad(btr_pcur_is_on_user_rec(&pcur));
+  do
+  {
+    rec_t *rec= cur->page_cur.rec;
+    ulint n_fields= rec_get_n_fields_old(rec);
 
-		rec = btr_pcur_get_rec(&pcur);
+    if (n_fields <= IBUF_REC_FIELD_USER + 1 || rec[4])
+      return DB_CORRUPTION;
 
-		/* Check if the entry is for this index page */
-		if (ibuf_rec_get_page_no(&mtr, rec) != page_id.page_no()
-		    || ibuf_rec_get_space(&mtr, rec) != page_id.space()) {
+    n_fields-= IBUF_REC_FIELD_USER;
 
-			if (block != NULL) {
-				page_header_reset_last_insert(block, &mtr);
-			}
+    ulint types_len, not_redundant;
 
-			goto reset_bit;
-		}
+    if (rec_get_1byte_offs_flag(rec))
+    {
+      if (rec_1_get_field_end_info(rec, 0) != 4 ||
+          rec_1_get_field_end_info(rec, 1) != 5 ||
+          rec_1_get_field_end_info(rec, 2) != 9)
+        return DB_CORRUPTION;
+      types_len= rec_1_get_field_end_info(rec, 3);
+    }
+    else
+    {
+      if (rec_2_get_field_end_info(rec, 0) != 4 ||
+          rec_2_get_field_end_info(rec, 1) != 5 ||
+          rec_2_get_field_end_info(rec, 2) != 9)
+        return DB_CORRUPTION;
+      types_len= rec_2_get_field_end_info(rec, 3);
+    }
 
-		if (err) {
-			fputs("InnoDB: Discarding record\n ", stderr);
-			rec_print_old(stderr, rec);
-			fputs("\nInnoDB: from the insert buffer!\n\n", stderr);
-		} else if (block != NULL && !rec_get_deleted_flag(rec, 0)) {
-			/* Now we have at pcur a record which should be
-			applied on the index page; NOTE that the call below
-			copies pointers to fields in rec, and we must
-			keep the latch to the rec page until the
-			insertion is finished! */
-			dtuple_t*	entry;
-			trx_id_t	max_trx_id;
-			dict_index_t*	dummy_index;
-			ibuf_op_t	op = ibuf_rec_get_op_type(&mtr, rec);
-
-			max_trx_id = page_get_max_trx_id(page_align(rec));
-			page_update_max_trx_id(block,
-					       buf_block_get_page_zip(block),
-					       max_trx_id, &mtr);
-
-			ut_ad(page_validate(page_align(rec), ibuf.index));
-
-			entry = ibuf_build_entry_from_ibuf_rec(
-				&mtr, rec, heap, &dummy_index);
-			ut_ad(!dummy_index->table->space);
-			dummy_index->table->space = space;
-			dummy_index->table->space_id = space->id;
-
-			ut_ad(page_validate(block->page.frame, dummy_index));
-
-			switch (op) {
-			case IBUF_OP_INSERT:
-#ifdef UNIV_IBUF_DEBUG
-				volume += rec_get_converted_size(
-					dummy_index, entry, 0);
-
-				volume += page_dir_calc_reserved_space(1);
-
-				ut_a(volume <= (4U << srv_page_size_shift)
-				     / IBUF_PAGE_SIZE_PER_FREE_SPACE);
-#endif
-				ibuf_insert_to_index_page(
-					entry, block, dummy_index, &mtr);
-				break;
-
-			case IBUF_OP_DELETE_MARK:
-				ibuf_set_del_mark(
-					entry, block, dummy_index, &mtr);
-				break;
-
-			case IBUF_OP_DELETE:
-				ibuf_delete(entry, block, dummy_index, &mtr);
-				/* Because ibuf_delete() will latch an
-				insert buffer bitmap page, commit mtr
-				before latching any further pages.
-				Store and restore the cursor position. */
-				ut_ad(rec == btr_pcur_get_rec(&pcur));
-				ut_ad(page_rec_is_user_rec(rec));
-				ut_ad(ibuf_rec_get_page_no(&mtr, rec)
-				      == page_id.page_no());
-				ut_ad(ibuf_rec_get_space(&mtr, rec)
-				      == page_id.space());
-
-				/* Mark the change buffer record processed,
-				so that it will not be merged again in case
-				the server crashes between the following
-				mtr_commit() and the subsequent mtr_commit()
-				of deleting the change buffer record. */
-				btr_rec_set_deleted<true>(
-					btr_pcur_get_block(&pcur),
-					btr_pcur_get_rec(&pcur), &mtr);
-
-				btr_pcur_store_position(&pcur, &mtr);
-				ibuf_btr_pcur_commit_specify_mtr(&pcur, &mtr);
-
-				ibuf_mtr_start(&mtr);
-				mtr.set_named_space(space);
-
-				block->page.lock.x_lock_recursive();
-				block->fix();
-				mtr.memo_push(block, MTR_MEMO_PAGE_X_FIX);
-
-				if (!ibuf_restore_pos(page_id, search_tuple,
-						      BTR_MODIFY_LEAF,
-						      &pcur, &mtr)) {
-
-					ut_ad(mtr.has_committed());
-					mops[op]++;
-					ibuf_dummy_index_free(dummy_index);
-					goto loop;
-				}
-
-				break;
-			default:
-				ut_error;
-			}
-
-			mops[op]++;
-
-			ibuf_dummy_index_free(dummy_index);
-		} else {
-			dops[ibuf_rec_get_op_type(&mtr, rec)]++;
-		}
+    if (types_len < 9 || (types_len - 9) / 6 != n_fields)
+      return DB_CORRUPTION;
 
-		/* Delete the record from ibuf */
-		if (ibuf_delete_rec(page_id, &pcur, search_tuple, &mtr)) {
-			/* Deletion was pessimistic and mtr was committed:
-			we start from the beginning again */
+    ibuf_op op= IBUF_OP_INSERT;
+    const ulint info_len= (types_len - 9) % 6;
 
-			ut_ad(mtr.has_committed());
-			goto loop;
-		} else if (btr_pcur_is_after_last_on_page(&pcur)) {
-			ibuf_mtr_commit(&mtr);
-			goto loop;
-		}
-	}
+    switch (info_len) {
+    default:
+      return DB_CORRUPTION;
+    case 0: case 1:
+      not_redundant= info_len;
+      break;
+    case 4:
+      not_redundant= rec[9 + 3];
+      if (rec[9 + 2] > IBUF_OP_DELETE || not_redundant > 1)
+        return DB_CORRUPTION;
+      op= static_cast<ibuf_op>(rec[9 + 2]);
+    }
 
-reset_bit:
-	if (space) {
-		ibuf_reset_bitmap(block, page_id, zip_size, &mtr);
-	}
+    const byte *const types= rec + 9 + info_len;
 
-	ibuf_mtr_commit(&mtr);
-	ut_free(pcur.old_rec_buf);
+    if (ibuf_rec_get_space(rec) != space_id ||
+        ibuf_rec_get_page_no(rec) != page_no)
+      break;
 
-	if (space) {
-		space->release();
-	}
+    if (!rec_get_deleted_flag(rec, 0))
+    {
+      /* Delete-mark the record so that it will not be applied again if
+      the server is killed before the completion of ibuf_upgrade(). */
+      btr_rec_set_deleted<true>(cur->page_cur.block, rec, mtr);
+
+      if (block)
+      {
+        page_header_reset_last_insert(block, mtr);
+        page_update_max_trx_id(block, buf_block_get_page_zip(block),
+                               page_get_max_trx_id(page_align(rec)), mtr);
+        dict_index_t *index;
+        mem_heap_t *heap = mem_heap_create(512);
+        dtuple_t *entry= ibuf_entry_build(rec, not_redundant, n_fields,
+                                          types, heap, index);
+        dict_table_t *table= index->table;
+        ut_ad(!table->space);
+        table->space= space;
+        table->space_id= space_id;
+
+        switch (op) {
+        case IBUF_OP_INSERT:
+          ibuf_insert_to_index_page(entry, block, index, mtr);
+          break;
+        case IBUF_OP_DELETE_MARK:
+          ibuf_set_del_mark(entry, block, index, mtr);
+          break;
+        case IBUF_OP_DELETE:
+          ibuf_delete(entry, block, index, mtr);
+          break;
+        }
+
+        mem_heap_free(heap);
+        dict_mem_index_free(index);
+        dict_mem_table_free(table);
+      }
+    }
 
-	mem_heap_free(heap);
+    if (dberr_t err= ibuf_move_to_next(cur, mtr))
+      return err;
+  }
+  while (!page_cur_is_after_last(&cur->page_cur));
 
-	ibuf.n_merges++;
-	ibuf_add_ops(ibuf.n_merged_ops, mops);
-	ibuf_add_ops(ibuf.n_discarded_ops, dops);
+  if (bitmap)
+    ibuf_reset(*bitmap, page_no, mtr);
 
-	return err;
+  return DB_SUCCESS;
 }
 
-/** Delete all change buffer entries for a tablespace,
-in DISCARD TABLESPACE, IMPORT TABLESPACE, or read-ahead.
-@param[in]	space		missing or to-be-discarded tablespace */
-void ibuf_delete_for_discarded_space(uint32_t space)
+ATTRIBUTE_COLD dberr_t ibuf_upgrade()
 {
-	btr_pcur_t	pcur;
-	const rec_t*	ibuf_rec;
-	mtr_t		mtr;
-
-	/* Counts for discarded operations. */
-	ulint		dops[IBUF_OP_COUNT];
-
-	dfield_t	dfield[IBUF_REC_FIELD_METADATA];
-	dtuple_t	search_tuple {0,IBUF_REC_FIELD_METADATA,
-				      IBUF_REC_FIELD_METADATA,dfield,0
-				      ,nullptr
-#ifdef UNIV_DEBUG
-				      ,DATA_TUPLE_MAGIC_N
-#endif /* UNIV_DEBUG */
-	};
-	byte space_id[4];
-	mach_write_to_4(space_id, space);
-
-	dfield_set_data(&dfield[0], space_id, 4);
-	dfield_set_data(&dfield[1], field_ref_zero, 1);
-	dfield_set_data(&dfield[2], field_ref_zero, 4);
-	dtuple_set_types_binary(&search_tuple, IBUF_REC_FIELD_METADATA);
-	/* Use page number 0 to build the search tuple so that we get the
-	cursor positioned at the first entry for this space id */
-
-	memset(dops, 0, sizeof(dops));
-	pcur.btr_cur.page_cur.index = ibuf.index;
-
-loop:
-	log_free_check();
-	ibuf_mtr_start(&mtr);
-
-	/* Position pcur in the insert buffer at the first entry for the
-	space */
-	if (btr_pcur_open_on_user_rec(&search_tuple, PAGE_CUR_GE,
-				      BTR_MODIFY_LEAF, &pcur, &mtr)
-	    != DB_SUCCESS) {
-		goto leave_loop;
-	}
-
-	if (!btr_pcur_is_on_user_rec(&pcur)) {
-		ut_ad(btr_pcur_is_after_last_on_page(&pcur));
-		goto leave_loop;
-	}
-
-	for (;;) {
-		ut_ad(btr_pcur_is_on_user_rec(&pcur));
-
-		ibuf_rec = btr_pcur_get_rec(&pcur);
+  if (srv_read_only_mode)
+  {
+    sql_print_error("InnoDB: innodb_read_only_mode prevents an upgrade");
+    return DB_READ_ONLY;
+  }
 
-		/* Check if the entry is for this space */
-		if (ibuf_rec_get_space(&mtr, ibuf_rec) != space) {
+  sql_print_information("InnoDB: Upgrading the change buffer");
 
-			goto leave_loop;
-		}
+#ifdef BTR_CUR_HASH_ADAPT
+  const bool ahi= btr_search_enabled;
+  if (ahi)
+    btr_search_disable();
+#endif
 
-		uint32_t page_no = ibuf_rec_get_page_no(&mtr, ibuf_rec);
+  dict_table_t *ibuf_table= dict_table_t::create({C_STRING_WITH_LEN("ibuf")},
+                                                 fil_system.sys_space,
+                                                 1, 0, 0, 0);
+  dict_index_t *ibuf_index=
+    dict_mem_index_create(ibuf_table, "CLUST_IND", DICT_CLUSTERED, 1);
+  ibuf_index->id= ibuf_index_id;
+  ibuf_index->n_uniq= REC_MAX_N_FIELDS;
+  ibuf_index->lock.SRW_LOCK_INIT(index_tree_rw_lock_key);
+  ibuf_index->page= FSP_IBUF_TREE_ROOT_PAGE_NO;
+  ut_d(ibuf_index->is_dummy= true);
+  ut_d(ibuf_index->cached= true);
+
+  size_t spaces=0, pages= 0;
+  dberr_t err;
+  mtr_t mtr;
+  {
+    btr_cur_t cur;
+    uint32_t prev_space_id= ~0U;
+    fil_space_t *space= nullptr;
 
-		dops[ibuf_rec_get_op_type(&mtr, ibuf_rec)]++;
+    log_free_check();
+    mtr.start();
+    err= cur.open_leaf(true, ibuf_index, BTR_CONT_MODIFY_TREE, &mtr);
 
-		/* Delete the record from ibuf */
-		if (ibuf_delete_rec(page_id_t(space, page_no),
-				    &pcur, &search_tuple, &mtr)) {
-			/* Deletion was pessimistic and mtr was committed:
-			we start from the beginning again */
+    if (err == DB_SUCCESS)
+    {
+      cur.page_cur.block->fix();
+      mtr.page_lock(cur.page_cur.block, RW_X_LATCH);
+      err= ibuf_move_to_next(&cur, &mtr);
+    }
 
-			ut_ad(mtr.has_committed());
-clear:
-			ut_free(pcur.old_rec_buf);
-			goto loop;
-		}
+    while (err == DB_SUCCESS && !page_cur_is_after_last(&cur.page_cur))
+    {
+      const uint32_t space_id= ibuf_rec_get_space(cur.page_cur.rec);
+      if (space_id != prev_space_id)
+      {
+        if (space)
+          space->release();
+        prev_space_id= space_id;
+        space= fil_space_t::get(space_id);
+        if (space)
+          mtr.set_named_space(space);
+        spaces++;
+      }
+      pages++;
+      err= ibuf_merge(space, &cur, &mtr);
+      if (err == DB_SUCCESS)
+      {
+        /* Move to the next user index page. We buffer-fix the current
+        change buffer leaf page to prevent it from being evicted
+        before we have started a new mini-transaction. */
+        cur.page_cur.block->fix();
+        mtr.commit();
+
+        if (recv_sys.report(time(nullptr)))
+        {
+          sql_print_information("InnoDB: merged changes to"
+                                " %zu tablespaces, %zu pages", spaces, pages);
+          service_manager_extend_timeout(INNODB_EXTEND_TIMEOUT_INTERVAL,
+                                         "merged changes to"
+                                         " %zu tablespaces, %zu pages",
+                                         spaces, pages);
+        }
+
+        log_free_check();
+        mtr.start();
+        mtr.page_lock(cur.page_cur.block, RW_X_LATCH);
+        if (space)
+          mtr.set_named_space(space);
+      }
+    }
+    mtr.commit();
+    if (space)
+      space->release();
+  }
 
-		if (btr_pcur_is_after_last_on_page(&pcur)) {
-			ibuf_mtr_commit(&mtr);
-			goto clear;
-		}
-	}
+  if (err == DB_SUCCESS)
+  {
+    mtr.start();
+    if (buf_block_t *root= buf_page_get_gen(ibuf_root, 0, RW_X_LATCH,
+                                            nullptr, BUF_GET, &mtr, &err))
+    {
+      page_create(root, &mtr, false);
+      mtr.write<2,mtr_t::MAYBE_NOP>(*root, PAGE_HEADER + PAGE_LEVEL +
+                                    root->page.frame, 0U);
+    }
+    mtr.commit();
 
-leave_loop:
-	ibuf_mtr_commit(&mtr);
-	ut_free(pcur.old_rec_buf);
+    while (err == DB_SUCCESS)
+      err= ibuf_remove_free_page(mtr);
 
-	ibuf_add_ops(ibuf.n_discarded_ops, dops);
-}
+    if (err == DB_SUCCESS_LOCKED_REC)
+      err= DB_SUCCESS;
+  }
 
-/******************************************************************//**
-Looks if the insert buffer is empty.
-@return true if empty */
-bool
-ibuf_is_empty(void)
-/*===============*/
-{
-	mtr_t		mtr;
+#ifdef BTR_CUR_HASH_ADAPT
+  if (ahi)
+    btr_search_enable();
+#endif
 
-	ibuf_mtr_start(&mtr);
+  ibuf_index->lock.free();
+  dict_mem_index_free(ibuf_index);
+  dict_mem_table_free(ibuf_table);
 
-	ut_d(mysql_mutex_lock(&ibuf_mutex));
-	const buf_block_t* root = ibuf_tree_root_get(&mtr);
-	bool is_empty = root && page_is_empty(root->page.frame);
-	ut_ad(!root || is_empty == ibuf.empty);
-	ut_d(mysql_mutex_unlock(&ibuf_mutex));
-	ibuf_mtr_commit(&mtr);
+  if (err)
+    sql_print_error("InnoDB: Unable to upgrade the change buffer");
+  else
+    sql_print_information("InnoDB: Upgraded the change buffer: "
+                          "%zu tablespaces, %zu pages", spaces, pages);
 
-	return(is_empty);
+  return err;
 }
 
-/******************************************************************//**
-Prints info of ibuf. */
-void
-ibuf_print(
-/*=======*/
-	FILE*	file)	/*!< in: file where to print */
+dberr_t ibuf_upgrade_needed()
 {
+  mtr_t mtr;
+  mtr.start();
+  mtr.x_lock_space(fil_system.sys_space);
+  dberr_t err;
+  const buf_block_t *header_page=
+    buf_page_get_gen(ibuf_header, 0, RW_S_LATCH, nullptr, BUF_GET, &mtr, &err);
 
-  mysql_mutex_lock(&ibuf_mutex);
-  if (ibuf.empty)
+  if (!header_page)
   {
-    mysql_mutex_unlock(&ibuf_mutex);
-    return;
+  err_exit:
+    sql_print_error("InnoDB: The change buffer is corrupted");
+    if (srv_force_recovery == SRV_FORCE_NO_LOG_REDO)
+      err= DB_SUCCESS;
+  func_exit:
+    mtr.commit();
+    return err;
   }
 
-  const ulint size= ibuf.size;
-  const ulint free_list_len= ibuf.free_list_len;
-  const ulint seg_size= ibuf.seg_size;
-  mysql_mutex_unlock(&ibuf_mutex);
-
-  fprintf(file,
-          "-------------\n"
-          "INSERT BUFFER\n"
-          "-------------\n"
-          "size " ULINTPF ", free list len " ULINTPF ","
-          " seg size " ULINTPF ", " ULINTPF " merges\n",
-          size, free_list_len, seg_size, ulint{ibuf.n_merges});
-  ibuf_print_ops("merged operations:\n", ibuf.n_merged_ops, file);
-  ibuf_print_ops("discarded operations:\n", ibuf.n_discarded_ops, file);
-}
-
-/** Check the insert buffer bitmaps on IMPORT TABLESPACE.
-@param[in]	trx	transaction
-@param[in,out]	space	tablespace being imported
-@return DB_SUCCESS or error code */
-dberr_t ibuf_check_bitmap_on_import(const trx_t* trx, fil_space_t* space)
-{
-	ut_ad(trx->mysql_thd);
-	ut_ad(space->purpose == FIL_TYPE_IMPORT);
-
-	const unsigned zip_size = space->zip_size();
-	const unsigned physical_size = space->physical_size();
-
-	uint32_t size= std::min(space->free_limit, space->size);
-
-	if (size == 0) {
-		return(DB_TABLE_NOT_FOUND);
-	}
-
-	mtr_t mtr;
-
-	mysql_mutex_lock(&ibuf_mutex);
-
-	/* The two bitmap pages (allocation bitmap and ibuf bitmap) repeat
-	every page_size pages. For example if page_size is 16 KiB, then the
-	two bitmap pages repeat every 16 KiB * 16384 = 256 MiB. In the loop
-	below page_no is measured in number of pages since the beginning of
-	the space, as usual. */
-
-	for (uint32_t page_no = 0; page_no < size; page_no += physical_size) {
-		if (trx_is_interrupted(trx)) {
-			mysql_mutex_unlock(&ibuf_mutex);
-			return(DB_INTERRUPTED);
-		}
-
-		mtr_start(&mtr);
-		ibuf_enter(&mtr);
-
-		buf_block_t* bitmap_page = ibuf_bitmap_get_map_page(
-			page_id_t(space->id, page_no), zip_size, &mtr);
-		if (!bitmap_page) {
-			mysql_mutex_unlock(&ibuf_mutex);
-			ibuf_exit(&mtr);
-			mtr.commit();
-			return DB_CORRUPTION;
-		}
-
-		if (buf_is_zeroes(span<const byte>(bitmap_page->page.frame,
-						   physical_size))) {
-			/* This means we got all-zero page instead of
-			ibuf bitmap page. The subsequent page should be
-			all-zero pages. */
-#ifdef UNIV_DEBUG
-			for (uint32_t curr_page = page_no + 1;
-			     curr_page < physical_size; curr_page++) {
-
-				buf_block_t* block = buf_page_get(
-					page_id_t(space->id, curr_page),
-					zip_size, RW_S_LATCH, &mtr);
-				page_t*	page = buf_block_get_frame(block);
-				ut_ad(buf_is_zeroes(span<const byte>(
-							    page,
-							    physical_size)));
-			}
-#endif /* UNIV_DEBUG */
-			ibuf_exit(&mtr);
-			mtr_commit(&mtr);
-			continue;
-		}
-
-		for (uint32_t i = FSP_IBUF_BITMAP_OFFSET + 1; i < physical_size;
-		     i++) {
-			const uint32_t offset = page_no + i;
-			const page_id_t	cur_page_id(space->id, offset);
-
-			if (ibuf_bitmap_page_get_bits(
-				    bitmap_page->page.frame,
-				    cur_page_id, zip_size,
-				    IBUF_BITMAP_IBUF, &mtr)) {
-
-				mysql_mutex_unlock(&ibuf_mutex);
-				ibuf_exit(&mtr);
-				mtr_commit(&mtr);
-
-				ib_errf(trx->mysql_thd,
-					IB_LOG_LEVEL_ERROR,
-					 ER_INNODB_INDEX_CORRUPT,
-					 "File %s page %u"
-					 " is wrongly flagged to belong to the"
-					 " insert buffer",
-					space->chain.start->name, offset);
-				return(DB_CORRUPTION);
-			}
-
-			if (ibuf_bitmap_page_get_bits(
-				    bitmap_page->page.frame,
-				    cur_page_id, zip_size,
-				    IBUF_BITMAP_BUFFERED, &mtr)) {
-
-				ib_errf(trx->mysql_thd,
-					IB_LOG_LEVEL_WARN,
-					ER_INNODB_INDEX_CORRUPT,
-					"Buffered changes"
-					" for file %s page %u are lost",
-					space->chain.start->name, offset);
-
-				/* Tolerate this error, so that
-				slightly corrupted tables can be
-				imported and dumped.  Clear the bit. */
-				ibuf_bitmap_page_set_bits<IBUF_BITMAP_BUFFERED>(
-					bitmap_page, cur_page_id,
-					physical_size, false, &mtr);
-			}
-		}
-
-		ibuf_exit(&mtr);
-		mtr_commit(&mtr);
-	}
-
-	mysql_mutex_unlock(&ibuf_mutex);
-	return(DB_SUCCESS);
-}
-
-void ibuf_set_bitmap_for_bulk_load(buf_block_t *block, mtr_t *mtr, bool reset)
-{
-  ut_a(page_is_leaf(block->page.frame));
-  const page_id_t id{block->page.id()};
-  const auto zip_size= block->zip_size();
-
-  if (buf_block_t *bitmap_page= ibuf_bitmap_get_map_page(id, zip_size, mtr))
+  const buf_block_t *root= buf_page_get_gen(ibuf_root, 0, RW_S_LATCH, nullptr,
+                                            BUF_GET, &mtr, &err);
+  if (!root)
+    goto err_exit;
+
+  if (UNIV_LIKELY(!page_has_siblings(root->page.frame)) &&
+      UNIV_LIKELY(!memcmp(root->page.frame + FIL_PAGE_TYPE, field_ref_zero,
+                          srv_page_size -
+                          (FIL_PAGE_DATA_END + FIL_PAGE_TYPE))))
+    /* the change buffer was removed; no need to upgrade */;
+  else if (page_is_comp(root->page.frame) ||
+           btr_page_get_index_id(root->page.frame) != ibuf_index_id ||
+           fil_page_get_type(root->page.frame) != FIL_PAGE_INDEX)
   {
-    if (ibuf_bitmap_page_get_bits(bitmap_page->page.frame, id, zip_size,
-                                  IBUF_BITMAP_BUFFERED, mtr))
-      ibuf_delete_recs(id);
-
-    ulint free_val= reset ? 0 : ibuf_index_page_calc_free(block);
-    /* FIXME: update the bitmap byte only once! */
-    ibuf_bitmap_page_set_bits<IBUF_BITMAP_FREE>
-      (bitmap_page, id, block->physical_size(), free_val, mtr);
-    ibuf_bitmap_page_set_bits<IBUF_BITMAP_BUFFERED>
-      (bitmap_page, id, block->physical_size(), false, mtr);
+    err= DB_CORRUPTION;
+    goto err_exit;
   }
+  else if (srv_read_only_mode)
+  {
+    sql_print_error("InnoDB: innodb_read_only=ON prevents an upgrade"
+                    " of the change buffer");
+    err= DB_READ_ONLY;
+  }
+  else if (srv_force_recovery != SRV_FORCE_NO_LOG_REDO)
+    err= DB_FAIL;
+
+  goto func_exit;
 }
diff --git a/storage/innobase/include/btr0btr.h b/storage/innobase/include/btr0btr.h
index a2aa46b62da..a397aa6b7f1 100644
--- a/storage/innobase/include/btr0btr.h
+++ b/storage/innobase/include/btr0btr.h
@@ -2,7 +2,7 @@
 
 Copyright (c) 1994, 2016, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2012, Facebook Inc.
-Copyright (c) 2014, 2022, MariaDB Corporation.
+Copyright (c) 2014, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -56,12 +56,8 @@ is acceptable for the program to die with a clear assert failure. */
 #define BTR_MAX_LEVELS		100
 
 #define BTR_LATCH_MODE_WITHOUT_FLAGS(latch_mode)		\
-	btr_latch_mode((latch_mode) & ~(BTR_INSERT	\
-				| BTR_DELETE_MARK		\
-				| BTR_RTREE_UNDO_INS		\
+	btr_latch_mode((latch_mode) & ~(BTR_RTREE_UNDO_INS	\
 				| BTR_RTREE_DELETE_MARK		\
-				| BTR_DELETE			\
-				| BTR_IGNORE_SEC_UNIQUE		\
 				| BTR_ALREADY_S_LATCHED		\
 				| BTR_LATCH_FOR_INSERT		\
 				| BTR_LATCH_FOR_DELETE))
@@ -79,6 +75,14 @@ btr_root_adjust_on_import(
 	const dict_index_t*	index)	/*!< in: index tree */
 	MY_ATTRIBUTE((warn_unused_result));
 
+/** Check a file segment header within a B-tree root page.
+@param offset      file segment header offset
+@param block       B-tree root page
+@param space       tablespace
+@return whether the segment header is valid */
+bool btr_root_fseg_validate(ulint offset, const buf_block_t &block,
+                            const fil_space_t &space);
+
 /** Report a decryption failure. */
 ATTRIBUTE_COLD void btr_decryption_failed(const dict_index_t &index);
 
@@ -86,12 +90,11 @@ ATTRIBUTE_COLD void btr_decryption_failed(const dict_index_t &index);
 @param[in]	index	index tree
 @param[in]	page	page number
 @param[in]	mode	latch mode
-@param[in]	merge	whether change buffer merge should be attempted
 @param[in,out]	mtr	mini-transaction
 @param[out]	err	error code
 @return block */
 buf_block_t *btr_block_get(const dict_index_t &index,
-                           uint32_t page, ulint mode, bool merge,
+                           uint32_t page, ulint mode,
                            mtr_t *mtr, dberr_t *err= nullptr);
 
 /**************************************************************//**
@@ -242,15 +245,7 @@ btr_root_raise_and_insert(
 	mtr_t*		mtr,	/*!< in: mtr */
 	dberr_t*	err)	/*!< out: error code */
 	MY_ATTRIBUTE((warn_unused_result));
-/*************************************************************//**
-Reorganizes an index page.
-
-IMPORTANT: On success, the caller will have to update IBUF_BITMAP_FREE
-if this is a compressed leaf page in a secondary index. This has to
-be done either within the same mini-transaction, or by invoking
-ibuf_reset_free_bits() before mtr_commit(). On uncompressed pages,
-IBUF_BITMAP_FREE is unaffected by reorganization.
-
+/** Reorganize an index page.
 @param cursor  page cursor
 @param mtr     mini-transaction
 @return error code
@@ -348,6 +343,7 @@ btr_check_node_ptr(
 /*===============*/
 	dict_index_t*	index,	/*!< in: index tree */
 	buf_block_t*	block,	/*!< in: index page */
+	que_thr_t*	thr,	/*!< in/out: query thread */
 	mtr_t*		mtr)	/*!< in: mtr */
 	MY_ATTRIBUTE((warn_unused_result));
 #endif /* UNIV_DEBUG */
@@ -451,15 +447,8 @@ btr_root_block_get(
 					or RW_X_LATCH */
 	mtr_t*			mtr,	/*!< in: mtr */
 	dberr_t*		err);	/*!< out: error code */
-/*************************************************************//**
-Reorganizes an index page.
-
-IMPORTANT: On success, the caller will have to update IBUF_BITMAP_FREE
-if this is a compressed leaf page in a secondary index. This has to
-be done either within the same mini-transaction, or by invoking
-ibuf_reset_free_bits() before mtr_commit(). On uncompressed pages,
-IBUF_BITMAP_FREE is unaffected by reorganization.
 
+/** Reorganize an index page.
 @return error code
 @retval DB_FAIL if reorganizing a ROW_FORMAT=COMPRESSED page failed */
 dberr_t btr_page_reorganize_block(
@@ -530,9 +519,10 @@ btr_lift_page_up(
 				must not be empty: use
 				btr_discard_only_page_on_level if the last
 				record from the page should be removed */
+	que_thr_t*	thr,	/*!< in/out: query thread for SPATIAL INDEX */
 	mtr_t*		mtr,	/*!< in/out: mini-transaction */
 	dberr_t*	err)	/*!< out: error code */
-	__attribute__((nonnull));
+	__attribute__((nonnull(1,2,4,5)));
 
 #define BTR_N_LEAF_PAGES	1
 #define BTR_TOTAL_SIZE		2
diff --git a/storage/innobase/include/btr0cur.h b/storage/innobase/include/btr0cur.h
index 49bc8a4ff1b..b317b3abbc3 100644
--- a/storage/innobase/include/btr0cur.h
+++ b/storage/innobase/include/btr0cur.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1994, 2019, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -56,11 +56,7 @@ enum {
 	BTR_KEEP_POS_FLAG = 8,
 	/** the caller is creating the index or wants to bypass the
 	index->info.online creation log */
-	BTR_CREATE_FLAG = 16,
-	/** the caller of btr_cur_optimistic_update() or
-	btr_cur_update_in_place() will take care of
-	updating IBUF_BITMAP_FREE */
-	BTR_KEEP_IBUF_BITMAP = 32
+	BTR_CREATE_FLAG = 16
 };
 
 /* btr_cur_latch_leaves() returns latched blocks and savepoints. */
@@ -156,8 +152,7 @@ If mode is PAGE_CUR_GE, then up_match will a have a sensible value.
                   PAGE_CUR_GE, as the latter may end up on the previous page of
                   the record! Inserts should always be made using PAGE_CUR_LE
                   to search the position!
-@param latch_mode BTR_SEARCH_LEAF, ..., ORed with at most one of BTR_INSERT,
-                  BTR_DELETE_MARK, or BTR_DELETE;
+@param latch_mode BTR_SEARCH_LEAF, ...
                   cursor->left_block is used to store a pointer to the left
                   neighbor page
 @param cursor     tree cursor; the cursor page is s- or x-latched, but see also
@@ -242,14 +237,8 @@ btr_cur_pessimistic_insert(
 See if there is enough place in the page modification log to log
 an update-in-place.
 
-@retval false if out of space; IBUF_BITMAP_FREE will be reset
-outside mtr if the page was recompressed
-@retval true if enough place;
-
-IMPORTANT: The caller will have to update IBUF_BITMAP_FREE if this is
-a secondary index leaf page. This has to be done either within the
-same mini-transaction, or by invoking ibuf_reset_free_bits() before
-mtr_commit(mtr). */
+@retval false if out of space
+@retval true if enough place */
 bool
 btr_cur_update_alloc_zip_func(
 /*==========================*/
@@ -291,7 +280,7 @@ Updates a record when the update causes no size changes in its fields.
 @return locking or undo log related error code, or
 @retval DB_SUCCESS on success
 @retval DB_ZIP_OVERFLOW if there is not enough space left
-on the compressed page (IBUF_BITMAP_FREE was reset outside mtr) */
+on a ROW_FORMAT=COMPRESSED page */
 dberr_t
 btr_cur_update_in_place(
 /*====================*/
@@ -712,34 +701,19 @@ enum btr_cur_method {
 				reference is stored in the field
 				hash_node, and might be necessary to
 				update */
-	BTR_CUR_BINARY,		/*!< success using the binary search */
-	BTR_CUR_INSERT_TO_IBUF,	/*!< performed the intended insert to
-				the insert buffer */
-	BTR_CUR_DEL_MARK_IBUF,	/*!< performed the intended delete
-				mark in the insert/delete buffer */
-	BTR_CUR_DELETE_IBUF,	/*!< performed the intended delete in
-				the insert/delete buffer */
-	BTR_CUR_DELETE_REF	/*!< row_purge_poss_sec() failed */
+	BTR_CUR_BINARY		/*!< success using the binary search */
 };
 
 /** The tree cursor: the definition appears here only for the compiler
 to know struct size! */
 struct btr_cur_t {
 	page_cur_t	page_cur;	/*!< page cursor */
-	purge_node_t*	purge_node;	/*!< purge node, for BTR_DELETE */
 	buf_block_t*	left_block;	/*!< this field is used to store
 					a pointer to the left neighbor
 					page, in the cases
 					BTR_SEARCH_PREV and
 					BTR_MODIFY_PREV */
 	/*------------------------------*/
-	que_thr_t*	thr;		/*!< this field is only used
-					when btr_cur_search_to_nth_level
-					is called for an index entry
-					insertion: the calling query
-					thread is passed here to be
-					used in the insert buffer */
-	/*------------------------------*/
 	/** The following fields are used in
 	btr_cur_search_to_nth_level to pass information: */
 	/* @{ */
diff --git a/storage/innobase/include/btr0types.h b/storage/innobase/include/btr0types.h
index 6118bfbc128..0c0f4a9cc79 100644
--- a/storage/innobase/include/btr0types.h
+++ b/storage/innobase/include/btr0types.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2015, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2018, 2022, MariaDB Corporation.
+Copyright (c) 2018, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -76,24 +76,8 @@ enum btr_latch_mode {
 	/** Continue modifying the entire B-tree. */
 	BTR_CONT_MODIFY_TREE = 4 | BTR_MODIFY_TREE,
 
-	/* BTR_INSERT, BTR_DELETE and BTR_DELETE_MARK are mutually
-	exclusive. */
-	/** The search tuple will be inserted to the secondary index
-	at the searched position.  When the leaf page is not in the
-	buffer pool, try to use the change buffer. */
-	BTR_INSERT = 64,
-
-	/** Try to delete mark a secondary index leaf page record at
-	the searched position using the change buffer when the page is
-	not in the buffer pool. */
-	BTR_DELETE_MARK	= 128,
-
-	/** Try to purge the record using the change buffer when the
-	secondary index leaf page is not in the buffer pool. */
-	BTR_DELETE = BTR_INSERT | BTR_DELETE_MARK,
-
 	/** The caller is already holding dict_index_t::lock S-latch. */
-	BTR_ALREADY_S_LATCHED = 256,
+	BTR_ALREADY_S_LATCHED = 16,
 	/** Search and S-latch a leaf page, assuming that the
 	dict_index_t::lock S-latch is being held. */
 	BTR_SEARCH_LEAF_ALREADY_S_LATCHED = BTR_SEARCH_LEAF
@@ -107,28 +91,15 @@ enum btr_latch_mode {
 	BTR_MODIFY_LEAF_ALREADY_LATCHED = BTR_MODIFY_LEAF
 	| BTR_ALREADY_S_LATCHED,
 
-	/** Attempt to delete-mark a secondary index record. */
-	BTR_DELETE_MARK_LEAF = BTR_MODIFY_LEAF | BTR_DELETE_MARK,
-	/** Attempt to delete-mark a secondary index record
-	while holding the dict_index_t::lock S-latch. */
-	BTR_DELETE_MARK_LEAF_ALREADY_S_LATCHED = BTR_DELETE_MARK_LEAF
-	| BTR_ALREADY_S_LATCHED,
-	/** Attempt to purge a secondary index record. */
-	BTR_PURGE_LEAF = BTR_MODIFY_LEAF | BTR_DELETE,
-	/** Attempt to purge a secondary index record
-	while holding the dict_index_t::lock S-latch. */
-	BTR_PURGE_LEAF_ALREADY_S_LATCHED = BTR_PURGE_LEAF
-	| BTR_ALREADY_S_LATCHED,
-
 	/** In the case of BTR_MODIFY_TREE, the caller specifies
 	the intention to delete record only. It is used to optimize
 	block->lock range.*/
-	BTR_LATCH_FOR_DELETE = 512,
+	BTR_LATCH_FOR_DELETE = 32,
 
 	/** In the case of BTR_MODIFY_TREE, the caller specifies
 	the intention to delete record only. It is used to optimize
 	block->lock range.*/
-	BTR_LATCH_FOR_INSERT = 1024,
+	BTR_LATCH_FOR_INSERT = 64,
 
 	/** Attempt to delete a record in the tree. */
 	BTR_PURGE_TREE = BTR_MODIFY_TREE | BTR_LATCH_FOR_DELETE,
@@ -136,12 +107,8 @@ enum btr_latch_mode {
 	/** Attempt to insert a record into the tree. */
 	BTR_INSERT_TREE = BTR_MODIFY_TREE | BTR_LATCH_FOR_INSERT,
 
-	/** This flag ORed to BTR_INSERT says that we can ignore possible
-	UNIQUE definition on secondary indexes when we decide if we can use
-	the insert buffer to speed up inserts */
-	BTR_IGNORE_SEC_UNIQUE = 2048,
 	/** Rollback in spatial index */
-	BTR_RTREE_UNDO_INS = 4096,
+	BTR_RTREE_UNDO_INS = 128,
 	/** Try to delete mark a spatial index record */
-	BTR_RTREE_DELETE_MARK = 8192
+	BTR_RTREE_DELETE_MARK = 256
 };
diff --git a/storage/innobase/include/buf0buf.h b/storage/innobase/include/buf0buf.h
index eb84aff8354..5fc8789f365 100644
--- a/storage/innobase/include/buf0buf.h
+++ b/storage/innobase/include/buf0buf.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1995, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2013, 2022, MariaDB Corporation.
+Copyright (c) 2013, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -48,10 +48,6 @@ Created 11/5/1995 Heikki Tuuri
 #define	BUF_GET_IF_IN_POOL	11	/*!< get if in pool */
 #define BUF_PEEK_IF_IN_POOL	12	/*!< get if in pool, do not make
 					the block young in the LRU list */
-#define BUF_GET_IF_IN_POOL_OR_WATCH	15
-					/*!< Get the page only if it's in the
-					buffer pool, if not then set a watch
-					on the page. */
 #define BUF_GET_POSSIBLY_FREED		16
 					/*!< Like BUF_GET, but do not mind
 					if the file page has been freed. */
@@ -194,11 +190,9 @@ buf_page_t *buf_page_get_zip(const page_id_t page_id, ulint zip_size);
 @param[in]	rw_latch		RW_S_LATCH, RW_X_LATCH, RW_NO_LATCH
 @param[in]	guess			guessed block or NULL
 @param[in]	mode			BUF_GET, BUF_GET_IF_IN_POOL,
-BUF_PEEK_IF_IN_POOL, or BUF_GET_IF_IN_POOL_OR_WATCH
+or BUF_PEEK_IF_IN_POOL
 @param[in,out]	mtr			mini-transaction
 @param[out]	err			DB_SUCCESS or error code
-@param[in]	allow_ibuf_merge	Allow change buffer merge while
-reading the pages from file.
 @return pointer to the block or NULL */
 buf_block_t*
 buf_page_get_gen(
@@ -208,9 +202,8 @@ buf_page_get_gen(
 	buf_block_t*		guess,
 	ulint			mode,
 	mtr_t*			mtr,
-	dberr_t*		err = NULL,
-	bool			allow_ibuf_merge = false)
-	MY_ATTRIBUTE((nonnull(6), warn_unused_result));
+	dberr_t*		err = NULL)
+	MY_ATTRIBUTE((nonnull(6)));
 
 /** This is the low level function used to get access to a database page.
 @param[in]	page_id			page id
@@ -218,14 +211,10 @@ buf_page_get_gen(
 @param[in]	rw_latch		RW_S_LATCH, RW_X_LATCH, RW_NO_LATCH
 @param[in]	guess			guessed block or NULL
 @param[in]	mode			BUF_GET, BUF_GET_IF_IN_POOL,
-BUF_PEEK_IF_IN_POOL, or BUF_GET_IF_IN_POOL_OR_WATCH
+or BUF_PEEK_IF_IN_POOL
 @param[in,out]	mtr			mini-transaction, or NULL if a
 					block with page_id is to be evicted
 @param[out]	err			DB_SUCCESS or error code
-@param[in]	allow_ibuf_merge	Allow change buffer merge to happen
-while reading the page from file
-then it makes sure that it does merging of change buffer changes while
-reading the page from file.
 @return pointer to the block or NULL */
 buf_block_t*
 buf_page_get_low(
@@ -235,8 +224,7 @@ buf_page_get_low(
 	buf_block_t*		guess,
 	ulint			mode,
 	mtr_t*			mtr,
-	dberr_t*		err,
-	bool			allow_ibuf_merge);
+	dberr_t*		err);
 
 /** Initialize a page in the buffer pool. The page is usually not read
 from a file even if it cannot be found in the buffer buf_pool. This is one
@@ -539,18 +527,16 @@ public:
   static constexpr uint32_t REMOVE_HASH= 2;
   /** smallest state() of a buffer page that is freed in the tablespace */
   static constexpr uint32_t FREED= 3;
+  /* unused state: 1U<<29 */
   /** smallest state() for a block that belongs to buf_pool.LRU */
-  static constexpr uint32_t UNFIXED= 1U << 29;
-  /** smallest state() of a block for which buffered changes may exist */
-  static constexpr uint32_t IBUF_EXIST= 2U << 29;
+  static constexpr uint32_t UNFIXED= 2U << 29;
   /** smallest state() of a (re)initialized page (no doublewrite needed) */
   static constexpr uint32_t REINIT= 3U << 29;
   /** smallest state() for an io-fixed block */
   static constexpr uint32_t READ_FIX= 4U << 29;
+  /* unused state: 5U<<29 */
   /** smallest state() for a write-fixed block */
-  static constexpr uint32_t WRITE_FIX= 5U << 29;
-  /** smallest state() for a write-fixed block with buffered changes */
-  static constexpr uint32_t WRITE_FIX_IBUF= 6U << 29;
+  static constexpr uint32_t WRITE_FIX= 6U << 29;
   /** smallest state() for a write-fixed block (no doublewrite was used) */
   static constexpr uint32_t WRITE_FIX_REINIT= 7U << 29;
   /** buf_pool.LRU status mask in state() */
@@ -562,8 +548,7 @@ public:
   byte *frame;
   /* @} */
   /** ROW_FORMAT=COMPRESSED page; zip.data (but not the data it points to)
-  is also protected by buf_pool.mutex;
-  !frame && !zip.data means an active buf_pool.watch */
+  is also protected by buf_pool.mutex */
   page_zip_des_t zip;
 #ifdef UNIV_DEBUG
   /** whether this->list is in buf_pool.zip_hash; protected by buf_pool.mutex */
@@ -696,13 +681,6 @@ public:
 
   bool is_freed() const
   { const auto s= state(); ut_ad(s >= FREED); return s < UNFIXED; }
-  bool is_ibuf_exist() const
-  {
-    const auto s= state();
-    ut_ad(s >= UNFIXED);
-    ut_ad(s < READ_FIX);
-    return (s & LRU_MASK) == IBUF_EXIST;
-  }
   bool is_reinit() const { return !(~state() & REINIT); }
 
   void set_reinit(uint32_t prev_state)
@@ -713,29 +691,10 @@ public:
     ut_ad(s < prev_state + UNFIXED);
   }
 
-  void set_ibuf_exist()
-  {
-    ut_ad(lock.is_write_locked());
-    ut_ad(id() < page_id_t(SRV_SPACE_ID_UPPER_BOUND, 0));
-    const auto s= state();
-    ut_ad(s >= UNFIXED);
-    ut_ad(s < READ_FIX);
-    ut_ad(s < IBUF_EXIST || s >= REINIT);
-    zip.fix.fetch_add(IBUF_EXIST - (LRU_MASK & s));
-  }
-  void clear_ibuf_exist()
-  {
-    ut_ad(lock.is_write_locked());
-    ut_ad(id() < page_id_t(SRV_SPACE_ID_UPPER_BOUND, 0));
-    ut_d(const auto s=) zip.fix.fetch_sub(IBUF_EXIST - UNFIXED);
-    ut_ad(s >= IBUF_EXIST);
-    ut_ad(s < REINIT);
-  }
-
   void read_unfix(uint32_t s)
   {
     ut_ad(lock.is_write_locked());
-    ut_ad(s == UNFIXED + 1 || s == IBUF_EXIST + 1 || s == REINIT + 1);
+    ut_ad(s == UNFIXED + 1 || s == REINIT + 1);
     ut_d(auto old_state=) zip.fix.fetch_add(s - READ_FIX);
     ut_ad(old_state >= READ_FIX);
     ut_ad(old_state < WRITE_FIX);
@@ -822,7 +781,7 @@ public:
   uint32_t fix(uint32_t count= 1)
   {
     ut_ad(count);
-    ut_ad(count < IBUF_EXIST);
+    ut_ad(count < REINIT);
     uint32_t f= zip.fix.fetch_add(count);
     ut_ad(f >= FREED);
     ut_ad(!((f ^ (f + 1)) & LRU_MASK));
@@ -1426,82 +1385,6 @@ public:
   }
 
 public:
-  /** @return whether the buffer pool contains a page
-  @tparam allow_watch  whether to allow watch_is_sentinel()
-  @param page_id       page identifier
-  @param chain         hash table chain for page_id.fold() */
-  template<bool allow_watch= false>
-  TRANSACTIONAL_INLINE
-  bool page_hash_contains(const page_id_t page_id, hash_chain &chain)
-  {
-    transactional_shared_lock_guard<page_hash_latch> g
-      {page_hash.lock_get(chain)};
-    buf_page_t *bpage= page_hash.get(page_id, chain);
-    if (bpage >= &watch[0] && bpage < &watch[UT_ARR_SIZE(watch)])
-    {
-      ut_ad(!bpage->in_zip_hash);
-      ut_ad(!bpage->zip.data);
-      if (!allow_watch)
-        bpage= nullptr;
-    }
-    return bpage;
-  }
-
-  /** Determine if a block is a sentinel for a buffer pool watch.
-  @param bpage page descriptor
-  @return whether bpage a sentinel for a buffer pool watch */
-  bool watch_is_sentinel(const buf_page_t &bpage)
-  {
-#ifdef SAFE_MUTEX
-    DBUG_ASSERT(mysql_mutex_is_owner(&mutex) ||
-                page_hash.lock_get(page_hash.cell_get(bpage.id().fold())).
-                is_locked());
-#endif /* SAFE_MUTEX */
-    ut_ad(bpage.in_file());
-    if (&bpage < &watch[0] || &bpage >= &watch[array_elements(watch)])
-      return false;
-    ut_ad(!bpage.in_zip_hash);
-    ut_ad(!bpage.zip.data);
-    return true;
-  }
-
-  /** Check if a watched page has been read.
-  This may only be called after !watch_set() and before invoking watch_unset().
-  @param id   page identifier
-  @return whether the page was read to the buffer pool */
-  TRANSACTIONAL_INLINE
-  bool watch_occurred(const page_id_t id)
-  {
-    hash_chain &chain= page_hash.cell_get(id.fold());
-    transactional_shared_lock_guard<page_hash_latch> g
-      {page_hash.lock_get(chain)};
-    /* The page must exist because watch_set() increments buf_fix_count. */
-    return !watch_is_sentinel(*page_hash.get(id, chain));
-  }
-
-  /** Register a watch for a page identifier. The caller must hold an
-  exclusive page hash latch. The *hash_lock may be released,
-  relocated, and reacquired.
-  @param id         page identifier
-  @param chain      hash table chain with exclusively held page_hash
-  @return a buffer pool block corresponding to id
-  @retval nullptr   if the block was not present, and a watch was installed */
-  inline buf_page_t *watch_set(const page_id_t id, hash_chain &chain);
-
-  /** Stop watching whether a page has been read in.
-  watch_set(id) must have returned nullptr before.
-  @param id         page identifier
-  @param chain      unlocked hash table chain */
-  void watch_unset(const page_id_t id, hash_chain &chain);
-
-  /** Remove the sentinel block for the watch before replacing it with a
-  real block. watch_unset() or watch_occurred() will notice
-  that the block has been replaced with the real block.
-  @param w          sentinel
-  @param chain      locked hash table chain
-  @return           w->state() */
-  inline uint32_t watch_remove(buf_page_t *w, hash_chain &chain);
-
   /** @return whether less than 1/4 of the buffer pool is available */
   TPOOL_SUPPRESS_TSAN
   bool running_out() const
@@ -1851,9 +1734,6 @@ public:
 # error "BUF_BUDDY_LOW > UNIV_ZIP_SIZE_MIN"
 #endif
 
-  /** Sentinels to detect if pages are read into the buffer pool while
-  a delete-buffering operation is pending. Protected by mutex. */
-  buf_page_t watch[innodb_purge_threads_MAX + 1];
   /** Reserve a buffer. */
   buf_tmp_buffer_t *io_buf_reserve() { return io_buf.reserve(); }
 
diff --git a/storage/innobase/include/buf0rea.h b/storage/innobase/include/buf0rea.h
index 986a792b97e..af72c544ebf 100644
--- a/storage/innobase/include/buf0rea.h
+++ b/storage/innobase/include/buf0rea.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1995, 2015, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2015, 2021, MariaDB Corporation.
+Copyright (c) 2015, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -24,8 +24,7 @@ The database buffer read
 Created 11/5/1995 Heikki Tuuri
 *******************************************************/
 
-#ifndef buf0rea_h
-#define buf0rea_h
+#pragma once
 
 #include "buf0buf.h"
 
@@ -56,21 +55,14 @@ void buf_read_page_background(fil_space_t *space, const page_id_t page_id,
 /** Applies a random read-ahead in buf_pool if there are at least a threshold
 value of accessed pages from the random read-ahead area. Does not read any
 page, not even the one at the position (space, offset), if the read-ahead
-mechanism is not activated. NOTE 1: the calling thread may own latches on
+mechanism is not activated. NOTE: the calling thread may own latches on
 pages: to avoid deadlocks this function must be written such that it cannot
-end up waiting for these latches! NOTE 2: the calling thread must want
-access to the page given: this rule is set to prevent unintended read-aheads
-performed by ibuf routines, a situation which could result in a deadlock if
-the OS does not support asynchronous i/o.
+end up waiting for these latches!
 @param[in]	page_id		page id of a page which the current thread
 wants to access
 @param[in]	zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@param[in]	ibuf		whether we are inside ibuf routine
-@return number of page read requests issued; NOTE that if we read ibuf
-pages, it may happen that the page at the given page number does not
-get read even if we return a positive value! */
-ulint
-buf_read_ahead_random(const page_id_t page_id, ulint zip_size, bool ibuf);
+@return number of page read requests issued */
+ulint buf_read_ahead_random(const page_id_t page_id, ulint zip_size);
 
 /** Applies linear read-ahead if in the buf_pool the page is a border page of
 a linear read-ahead area and all the pages in the area have been accessed.
@@ -91,26 +83,12 @@ only very improbably.
 NOTE 2: the calling thread may own latches on pages: to avoid deadlocks this
 function must be written such that it cannot end up waiting for these
 latches!
-NOTE 3: the calling thread must want access to the page given: this rule is
-set to prevent unintended read-aheads performed by ibuf routines, a situation
-which could result in a deadlock if the OS does not support asynchronous io.
 @param[in]	page_id		page id; see NOTE 3 above
 @param[in]	zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@param[in]	ibuf		whether if we are inside ibuf routine
 @return number of page read requests issued */
-ulint
-buf_read_ahead_linear(const page_id_t page_id, ulint zip_size, bool ibuf);
+ulint buf_read_ahead_linear(const page_id_t page_id, ulint zip_size);
 
 /** Issue read requests for pages that need to be recovered.
 @param space_id	tablespace identifier
 @param page_nos	page numbers to read, in ascending order */
 void buf_read_recv_pages(uint32_t space_id, st_::span<uint32_t> page_nos);
-
-/** @name Modes used in read-ahead @{ */
-/** read only pages belonging to the insert buffer tree */
-#define BUF_READ_IBUF_PAGES_ONLY	131
-/** read any page */
-#define BUF_READ_ANY_PAGE		132
-/* @} */
-
-#endif
diff --git a/storage/innobase/include/data0type.h b/storage/innobase/include/data0type.h
index 3d63ddb767c..d4885186087 100644
--- a/storage/innobase/include/data0type.h
+++ b/storage/innobase/include/data0type.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -33,7 +33,6 @@ Created 1/16/1996 Heikki Tuuri
 /** @return whether a length is actually stored in a field */
 #define len_is_stored(len) (len != UNIV_SQL_NULL && len != UNIV_SQL_DEFAULT)
 
-extern ulint	data_mysql_default_charset_coll;
 #define DATA_MYSQL_BINARY_CHARSET_COLL 63
 
 /* SQL data type struct */
@@ -196,14 +195,6 @@ constexpr uint8_t DATA_MBR_LEN= uint8_t(SPDIMS * 2 * sizeof(double));
 
 /*-------------------------------------------*/
 
-/* This many bytes we need to store the type information affecting the
-alphabetical order for a single field and decide the storage size of an
-SQL null*/
-#define DATA_ORDER_NULL_TYPE_BUF_SIZE		4
-/* In the >= 4.1.x storage format we add 2 bytes more so that we can also
-store the charset-collation number; one byte is left unused, though */
-#define DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE	6
-
 /* Maximum multi-byte character length in bytes, plus 1 */
 #define DATA_MBMAX	8
 
@@ -344,13 +335,11 @@ charset-collation code.
 				DATA_BINARY_TYPE etc.
 @param[in]	charset_coll	character-set collation code
 @return precise type, including the charset-collation code */
-UNIV_INLINE
-uint32_t
-dtype_form_prtype(ulint old_prtype, ulint charset_coll)
+inline uint32_t dtype_form_prtype(ulint old_prtype, ulint charset_coll)
 {
-	ut_ad(old_prtype < 256 * 256);
-	ut_ad(charset_coll <= MAX_CHAR_COLL_NUM);
-	return(uint32_t(old_prtype + (charset_coll << 16)));
+  ut_ad(old_prtype <= 0xffff);
+  ut_ad(charset_coll <= MAX_CHAR_COLL_NUM);
+  return uint32_t(old_prtype | (charset_coll << 16));
 }
 
 /*********************************************************************//**
@@ -439,40 +428,6 @@ dtype_get_sql_null_size(
 	const dtype_t*	type,	/*!< in: type */
 	ulint		comp);	/*!< in: nonzero=ROW_FORMAT=COMPACT  */
 
-/**********************************************************************//**
-Reads to a type the stored information which determines its alphabetical
-ordering and the storage size of an SQL NULL value. */
-UNIV_INLINE
-void
-dtype_read_for_order_and_null_size(
-/*===============================*/
-	dtype_t*	type,	/*!< in: type struct */
-	const byte*	buf);	/*!< in: buffer for the stored order info */
-/**********************************************************************//**
-Stores for a type the information which determines its alphabetical ordering
-and the storage size of an SQL NULL value. This is the >= 4.1.x storage
-format. */
-UNIV_INLINE
-void
-dtype_new_store_for_order_and_null_size(
-/*====================================*/
-	byte*		buf,	/*!< in: buffer for
-				DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE
-				bytes where we store the info */
-	const dtype_t*	type,	/*!< in: type struct */
-	ulint		prefix_len);/*!< in: prefix length to
-				replace type->len, or 0 */
-/**********************************************************************//**
-Reads to a type the stored information which determines its alphabetical
-ordering and the storage size of an SQL NULL value. This is the 4.1.x storage
-format. */
-UNIV_INLINE
-void
-dtype_new_read_for_order_and_null_size(
-/*===================================*/
-	dtype_t*	type,	/*!< in: type struct */
-	const byte*	buf);	/*!< in: buffer for stored type order info */
-
 /*********************************************************************//**
 Validates a data type structure.
 @return TRUE if ok */
@@ -494,8 +449,6 @@ struct dict_col_t;
 If you add fields to this structure, be sure to initialize them everywhere.
 This structure is initialized in the following functions:
 dtype_set()
-dtype_read_for_order_and_null_size()
-dtype_new_read_for_order_and_null_size()
 sym_tab_add_null_lit() */
 
 struct dtype_t{
diff --git a/storage/innobase/include/data0type.inl b/storage/innobase/include/data0type.inl
index 329cee5d190..add6c211bb9 100644
--- a/storage/innobase/include/data0type.inl
+++ b/storage/innobase/include/data0type.inl
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2014, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2020, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -183,126 +183,6 @@ dtype_get_mbmaxlen(
 	return type->mbmaxlen;
 }
 
-/**********************************************************************//**
-Stores for a type the information which determines its alphabetical ordering
-and the storage size of an SQL NULL value. This is the >= 4.1.x storage
-format. */
-UNIV_INLINE
-void
-dtype_new_store_for_order_and_null_size(
-/*====================================*/
-	byte*		buf,	/*!< in: buffer for
-				DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE
-				bytes where we store the info */
-	const dtype_t*	type,	/*!< in: type struct */
-	ulint		prefix_len)/*!< in: prefix length to
-				replace type->len, or 0 */
-{
-	compile_time_assert(6 == DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE);
-
-	ulint	len;
-
-	ut_ad(type);
-	ut_ad(type->mtype >= DATA_VARCHAR);
-	ut_ad(type->mtype <= DATA_MTYPE_MAX);
-
-	buf[0] = (byte)(type->mtype & 0xFFUL);
-
-	if (type->prtype & DATA_BINARY_TYPE) {
-		buf[0] |= 128;
-	}
-
-	/* In versions < 4.1.2 we had:	if (type->prtype & DATA_NONLATIN1) {
-	buf[0] |= 64;
-	}
-	*/
-
-	buf[1] = (byte)(type->prtype & 0xFFUL);
-
-	len = prefix_len ? prefix_len : type->len;
-
-	mach_write_to_2(buf + 2, len & 0xFFFFUL);
-
-	ut_ad(dtype_get_charset_coll(type->prtype) <= MAX_CHAR_COLL_NUM);
-	mach_write_to_2(buf + 4, dtype_get_charset_coll(type->prtype));
-
-	if (type->prtype & DATA_NOT_NULL) {
-		buf[4] |= 128;
-	}
-}
-
-/**********************************************************************//**
-Reads to a type the stored information which determines its alphabetical
-ordering and the storage size of an SQL NULL value. This is the < 4.1.x
-storage format. */
-UNIV_INLINE
-void
-dtype_read_for_order_and_null_size(
-/*===============================*/
-	dtype_t*	type,	/*!< in: type struct */
-	const byte*	buf)	/*!< in: buffer for stored type order info */
-{
-	compile_time_assert(4 == DATA_ORDER_NULL_TYPE_BUF_SIZE);
-	type->mtype = buf[0] & 63;
-	type->prtype = buf[1];
-
-	if (buf[0] & 128) {
-		type->prtype |= DATA_BINARY_TYPE;
-	}
-
-	type->len = mach_read_from_2(buf + 2);
-
-	type->prtype = dtype_form_prtype(type->prtype,
-					 data_mysql_default_charset_coll);
-	dtype_set_mblen(type);
-}
-
-/**********************************************************************//**
-Reads to a type the stored information which determines its alphabetical
-ordering and the storage size of an SQL NULL value. This is the >= 4.1.x
-storage format. */
-UNIV_INLINE
-void
-dtype_new_read_for_order_and_null_size(
-/*===================================*/
-	dtype_t*	type,	/*!< in: type struct */
-	const byte*	buf)	/*!< in: buffer for stored type order info */
-{
-	compile_time_assert(6 == DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE);
-
-	type->mtype = buf[0] & 63;
-	type->prtype = buf[1];
-
-	if (buf[0] & 128) {
-		type->prtype |= DATA_BINARY_TYPE;
-	}
-
-	if (buf[4] & 128) {
-		type->prtype |= DATA_NOT_NULL;
-	}
-
-	type->len = mach_read_from_2(buf + 2);
-
-	ulint charset_coll = mach_read_from_2(buf + 4) & CHAR_COLL_MASK;
-
-	if (dtype_is_string_type(type->mtype)) {
-		ut_a(charset_coll <= MAX_CHAR_COLL_NUM);
-
-		if (charset_coll == 0) {
-			/* This insert buffer record was inserted with MySQL
-			version < 4.1.2, and the charset-collation code was not
-			explicitly stored to dtype->prtype at that time. It
-			must be the default charset-collation of this MySQL
-			installation. */
-
-			charset_coll = data_mysql_default_charset_coll;
-		}
-
-		type->prtype = dtype_form_prtype(type->prtype, charset_coll);
-	}
-	dtype_set_mblen(type);
-}
-
 /***********************************************************************//**
 Returns the size of a fixed size data type, 0 if not a fixed size type.
 @return fixed size, or 0 */
diff --git a/storage/innobase/include/dict0dict.h b/storage/innobase/include/dict0dict.h
index 8daa07160a3..1002213e61c 100644
--- a/storage/innobase/include/dict0dict.h
+++ b/storage/innobase/include/dict0dict.h
@@ -2,7 +2,7 @@
 
 Copyright (c) 1996, 2018, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2012, Facebook Inc.
-Copyright (c) 2013, 2022, MariaDB Corporation.
+Copyright (c) 2013, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -634,8 +634,6 @@ dict_table_get_next_index(
 #define dict_index_is_auto_gen_clust(index) (index)->is_gen_clust()
 #define dict_index_is_unique(index) (index)->is_unique()
 #define dict_index_is_spatial(index) (index)->is_spatial()
-#define dict_index_is_ibuf(index) (index)->is_ibuf()
-#define dict_index_is_sec_or_ibuf(index) !(index)->is_primary()
 #define dict_index_has_virtual(index) (index)->has_virtual()
 
 /** Get all the FTS indexes on a table.
diff --git a/storage/innobase/include/dict0load.h b/storage/innobase/include/dict0load.h
index f7d33d5b43b..bd55848a776 100644
--- a/storage/innobase/include/dict0load.h
+++ b/storage/innobase/include/dict0load.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -39,9 +39,7 @@ Created 4/24/1996 Heikki Tuuri
 /** A stack of table names related through foreign key constraints */
 typedef std::deque<const char*, ut_allocator<const char*> >	dict_names_t;
 
-/** Check each tablespace found in the data dictionary.
-Then look at each table defined in SYS_TABLES that has a space_id > 0
-to find all the file-per-table tablespaces.
+/** Open each tablespace found in the data dictionary.
 
 In a crash recovery we already have some tablespace objects created from
 processing the REDO log. We will compare the
@@ -50,7 +48,7 @@ tablespace file. In addition, more validation will be done if recovery
 was needed and force_recovery is not set.
 
 We also scan the biggest space id, and store it to fil_system. */
-void dict_check_tablespaces_and_store_max_id();
+void dict_load_tablespaces();
 
 /** Make sure the data_file_name is saved in dict_table_t if needed.
 @param[in,out]	table		Table object */
diff --git a/storage/innobase/include/dict0mem.h b/storage/innobase/include/dict0mem.h
index c76262ff5be..d9ef949ac13 100644
--- a/storage/innobase/include/dict0mem.h
+++ b/storage/innobase/include/dict0mem.h
@@ -64,7 +64,6 @@ combination of types */
 				auto-generated clustered indexes,
 				also DICT_UNIQUE will be set */
 #define DICT_UNIQUE	2	/*!< unique index */
-#define	DICT_IBUF	8	/*!< insert buffer tree */
 #define	DICT_CORRUPT	16	/*!< bit to store the corrupted flag
 				in SYS_INDEXES.TYPE */
 #define	DICT_FTS	32	/* FTS index; can't be combined with the
@@ -995,7 +994,7 @@ struct dict_index_t {
 # define DICT_INDEX_MERGE_THRESHOLD_DEFAULT 50
 	unsigned	type:DICT_IT_BITS;
 				/*!< index type (DICT_CLUSTERED, DICT_UNIQUE,
-				DICT_IBUF, DICT_CORRUPT) */
+				DICT_CORRUPT) */
 #define MAX_KEY_LENGTH_BITS 12
 	unsigned	trx_id_offset:MAX_KEY_LENGTH_BITS;
 				/*!< position of the trx id column
@@ -1184,12 +1183,8 @@ public:
 	/** @return whether instant ALTER TABLE is in effect */
 	inline bool is_instant() const;
 
-	/** @return whether the index is the primary key index
-	(not the clustered index of the change buffer) */
-	bool is_primary() const
-	{
-		return DICT_CLUSTERED == (type & (DICT_CLUSTERED | DICT_IBUF));
-	}
+	/** @return whether the index is the primary key index */
+	bool is_primary() const { return is_clust(); }
 
 	/** @return whether this is a generated clustered index */
 	bool is_gen_clust() const { return type == DICT_CLUSTERED; }
@@ -1203,16 +1198,13 @@ public:
 	/** @return whether this is a spatial index */
 	bool is_spatial() const { return UNIV_UNLIKELY(type & DICT_SPATIAL); }
 
-	/** @return whether this is the change buffer */
-	bool is_ibuf() const { return UNIV_UNLIKELY(type & DICT_IBUF); }
-
 	/** @return whether this index requires locking */
-	bool has_locking() const { return !is_ibuf(); }
+	static constexpr bool has_locking() { return true; }
 
 	/** @return whether this is a normal B-tree index
         (not the change buffer, not SPATIAL or FULLTEXT) */
 	bool is_btree() const {
-		return UNIV_LIKELY(!(type & (DICT_IBUF | DICT_SPATIAL
+		return UNIV_LIKELY(!(type & (DICT_SPATIAL
 					     | DICT_FTS | DICT_CORRUPT)));
 	}
 
diff --git a/storage/innobase/include/dict0types.h b/storage/innobase/include/dict0types.h
index 271e4e1fb76..82a0f780723 100644
--- a/storage/innobase/include/dict0types.h
+++ b/storage/innobase/include/dict0types.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2015, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2013, 2022, MariaDB Corporation.
+Copyright (c) 2013, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -48,10 +48,6 @@ struct dict_add_v_col_t;
 #define	DICT_HDR_SPACE		0	/* the SYSTEM tablespace */
 #define	DICT_HDR_PAGE_NO	FSP_DICT_HDR_PAGE_NO
 
-/* The ibuf table and indexes's ID are assigned as the number
-DICT_IBUF_ID_MIN plus the space id */
-#define DICT_IBUF_ID_MIN	0xFFFFFFFF00000000ULL
-
 typedef ib_id_t		table_id_t;
 typedef ib_id_t		index_id_t;
 
@@ -136,13 +132,6 @@ struct table_name_t
 	inline bool is_temporary() const;
 };
 
-#if defined UNIV_DEBUG || defined UNIV_IBUF_DEBUG
-/** Dump the change buffer at startup */
-extern my_bool		ibuf_dump;
-/** Flag to control insert buffer debugging. */
-extern uint		ibuf_debug;
-#endif /* UNIV_DEBUG || UNIV_IBUF_DEBUG */
-
 /** Shift for spatial status */
 #define SPATIAL_STATUS_SHIFT	12
 
diff --git a/storage/innobase/include/fil0fil.h b/storage/innobase/include/fil0fil.h
index 210f365ddd8..65ca704b6d8 100644
--- a/storage/innobase/include/fil0fil.h
+++ b/storage/innobase/include/fil0fil.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1995, 2017, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2013, 2022, MariaDB Corporation.
+Copyright (c) 2013, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -1247,11 +1247,11 @@ constexpr uint16_t FIL_PAGE_RTREE= 17854;
 constexpr uint16_t FIL_PAGE_UNDO_LOG= 2;
 /** Index node (of file-in-file metadata) */
 constexpr uint16_t FIL_PAGE_INODE= 3;
-/** Insert buffer free list */
+/** Former change buffer free list */
 constexpr uint16_t FIL_PAGE_IBUF_FREE_LIST= 4;
 /** Freshly allocated page */
 constexpr uint16_t FIL_PAGE_TYPE_ALLOCATED= 0;
-/** Change buffer bitmap (pages n*innodb_page_size+1) */
+/** Former change buffer bitmap pages (pages n*innodb_page_size+1) */
 constexpr uint16_t FIL_PAGE_IBUF_BITMAP= 5;
 /** System page */
 constexpr uint16_t FIL_PAGE_TYPE_SYS= 6;
diff --git a/storage/innobase/include/fsp0types.h b/storage/innobase/include/fsp0types.h
index 9a23e840380..757ead55d03 100644
--- a/storage/innobase/include/fsp0types.h
+++ b/storage/innobase/include/fsp0types.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1995, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2014, 2022, MariaDB Corporation.
+Copyright (c) 2014, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -157,28 +157,20 @@ this many file pages */
 /* This has been replaced with either srv_page_size or page_zip->size. */
 
 /** @name The space low address page map
-The pages at FSP_XDES_OFFSET and FSP_IBUF_BITMAP_OFFSET are repeated
+The 2 pages at FSP_XDES_OFFSET are repeated
 every XDES_DESCRIBED_PER_PAGE pages in every tablespace. */
 /* @{ */
 /*--------------------------------------*/
 #define FSP_XDES_OFFSET			0U	/* !< extent descriptor */
-#define FSP_IBUF_BITMAP_OFFSET		1U	/* !< insert buffer bitmap */
-				/* The ibuf bitmap pages are the ones whose
-				page number is the number above plus a
-				multiple of XDES_DESCRIBED_PER_PAGE */
-
 #define FSP_FIRST_INODE_PAGE_NO		2U	/*!< in every tablespace */
 				/* The following pages exist
 				in the system tablespace (space 0). */
-#define FSP_IBUF_HEADER_PAGE_NO		3U	/*!< insert buffer
+#define FSP_IBUF_HEADER_PAGE_NO		3U	/*!< former change buffer
 						header page, in
 						tablespace 0 */
-#define FSP_IBUF_TREE_ROOT_PAGE_NO	4U	/*!< insert buffer
+#define FSP_IBUF_TREE_ROOT_PAGE_NO	4U	/*!< former change buffer
 						B-tree root page in
 						tablespace 0 */
-				/* The ibuf tree root page number in
-				tablespace 0; its fseg inode is on the page
-				number FSP_FIRST_INODE_PAGE_NO */
 #define FSP_TRX_SYS_PAGE_NO		5U	/*!< transaction
 						system header, in
 						tablespace 0 */
diff --git a/storage/innobase/include/gis0rtree.h b/storage/innobase/include/gis0rtree.h
index 777f2432c93..12b7eb785be 100644
--- a/storage/innobase/include/gis0rtree.h
+++ b/storage/innobase/include/gis0rtree.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2014, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -94,7 +94,29 @@ rtr_page_split_and_insert(
 	const dtuple_t*	tuple,	/*!< in: tuple to insert */
 	ulint		n_ext,	/*!< in: number of externally stored columns */
 	mtr_t*		mtr,	/*!< in: mtr */
-	dberr_t*	err);	/*!< out: error code */
+	dberr_t*	err,	/*!< out: error code */
+	que_thr_t*	thr);	/*!< in: query thread */
+
+/*************************************************************//**
+Makes tree one level higher by splitting the root, and inserts the tuple.
+NOTE that the operation of this function must always succeed,
+we cannot reverse it: therefore enough free disk space must be
+guaranteed to be available before this function is called.
+@return inserted record */
+rec_t*
+rtr_root_raise_and_insert(
+	ulint		flags,	/*!< in: undo logging and locking flags */
+	btr_cur_t*	cursor,	/*!< in: cursor at which to insert: must be
+				on the root page; when the function returns,
+				the cursor is positioned on the predecessor
+				of the inserted record */
+	rec_offs**	offsets,/*!< out: offsets on inserted record */
+	mem_heap_t**	heap,	/*!< in/out: pointer to memory heap, or NULL */
+	const dtuple_t*	tuple,	/*!< in: tuple to insert */
+	ulint		n_ext,	/*!< in: number of externally stored columns */
+	mtr_t*		mtr,	/*!< in: mtr */
+	dberr_t*	err,	/*!< out: error code */
+	que_thr_t*	thr);	/*!< in: query thread */
 
 /**************************************************************//**
 Sets the child node mbr in a node pointer. */
@@ -205,8 +227,8 @@ rtr_create_rtr_info(
 	bool		init_matches,	/*!< in: Whether to initiate the
 					"matches" structure for collecting
 					matched leaf records */
-	btr_cur_t*	cursor,		/*!< in: tree search cursor */
-	dict_index_t*	index);		/*!< in: index struct */
+	que_thr_t*	thr,		/*!< in/out: query thread */
+	btr_cur_t*	cursor);	/*!< in: tree search cursor */
 
 /********************************************************************//**
 Update a btr_cur_t with rtr_info */
@@ -261,8 +283,10 @@ rtr_get_mbr_from_tuple(
 				about parent nodes in search
 @param[in,out]	cursor		cursor on node pointer record,
 				its page x-latched
+@param[in,out]	thr		query thread
 @return whether the cursor was successfully positioned */
-bool rtr_page_get_father(mtr_t *mtr, btr_cur_t *sea_cur, btr_cur_t *cursor)
+bool rtr_page_get_father(mtr_t *mtr, btr_cur_t *sea_cur, btr_cur_t *cursor,
+                         que_thr_t *thr)
   MY_ATTRIBUTE((nonnull(1,3), warn_unused_result));
 
 /************************************************************//**
@@ -274,11 +298,12 @@ rtr_page_get_father_block(
 /*======================*/
 	rec_offs*	offsets,/*!< in: work area for the return value */
 	mem_heap_t*	heap,	/*!< in: memory heap to use */
-	mtr_t*		mtr,	/*!< in: mtr */
 	btr_cur_t*	sea_cur,/*!< in: search cursor, contains information
 				about parent nodes in search */
-	btr_cur_t*	cursor);/*!< out: cursor on node pointer record,
+	btr_cur_t*	cursor,	/*!< out: cursor on node pointer record,
 				its page x-latched */
+	que_thr_t*	thr,	/*!< in/out: query thread */
+	mtr_t*		mtr);	/*!< in/out: mtr */
 /**************************************************************//**
 Store the parent path cursor
 @return number of cursor stored */
@@ -297,10 +322,10 @@ Initializes and opens a persistent cursor to an index tree. It should be
 closed with btr_pcur_close. */
 bool
 rtr_pcur_open(
-	dict_index_t*	index,	/*!< in: index */
 	const dtuple_t*	tuple,	/*!< in: tuple on which search done */
 	btr_latch_mode	latch_mode,/*!< in: BTR_SEARCH_LEAF, ... */
 	btr_pcur_t*	cursor,	/*!< in: memory buffer for persistent cursor */
+	que_thr_t*	thr,	/*!< in/out; query thread */
 	mtr_t*		mtr)	/*!< in: mtr */
 	MY_ATTRIBUTE((warn_unused_result));
 
diff --git a/storage/innobase/include/gis0rtree.inl b/storage/innobase/include/gis0rtree.inl
index 5101eeb6f7a..460496d1978 100644
--- a/storage/innobase/include/gis0rtree.inl
+++ b/storage/innobase/include/gis0rtree.inl
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2014, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2021, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -240,6 +240,9 @@ rtr_info_reinit_in_cursor(
 	bool		need_prdt)	/*!< in: Whether predicate lock is
 					needed */
 {
+	que_thr_t* thr = cursor->rtr_info->thr;
+	ut_ad(thr);
 	rtr_clean_rtr_info(cursor->rtr_info, false);
 	rtr_init_rtr_info(cursor->rtr_info, need_prdt, cursor, index, true);
+	cursor->rtr_info->thr = thr;
 }
diff --git a/storage/innobase/include/ibuf0ibuf.h b/storage/innobase/include/ibuf0ibuf.h
index c246b2ef513..d1ff331fe21 100644
--- a/storage/innobase/include/ibuf0ibuf.h
+++ b/storage/innobase/include/ibuf0ibuf.h
@@ -1,7 +1,6 @@
 /*****************************************************************************
 
-Copyright (c) 1997, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2016, 2022, MariaDB Corporation.
+Copyright (c) 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -17,420 +16,40 @@ this program; if not, write to the Free Software Foundation, Inc.,
 
 *****************************************************************************/
 
-/**************************************************//**
-@file include/ibuf0ibuf.h
-Insert buffer
-
-Created 7/19/1997 Heikki Tuuri
-*******************************************************/
-
-#ifndef ibuf0ibuf_h
-#define ibuf0ibuf_h
-
-#include "mtr0mtr.h"
-#include "dict0mem.h"
-#include "fsp0fsp.h"
-
-/** Default value for maximum on-disk size of change buffer in terms
-of percentage of the buffer pool. */
-#define CHANGE_BUFFER_DEFAULT_SIZE	(25)
-
-/* Possible operations buffered in the insert/whatever buffer. See
-ibuf_insert(). DO NOT CHANGE THE VALUES OF THESE, THEY ARE STORED ON DISK. */
-typedef enum {
-	IBUF_OP_INSERT = 0,
-	IBUF_OP_DELETE_MARK = 1,
-	IBUF_OP_DELETE = 2,
-
-	/* Number of different operation types. */
-	IBUF_OP_COUNT = 3
-} ibuf_op_t;
-
-/** Combinations of operations that can be buffered.
-@see innodb_change_buffering_names */
-enum ibuf_use_t {
-	IBUF_USE_NONE = 0,
-	IBUF_USE_INSERT,	/* insert */
-	IBUF_USE_DELETE_MARK,	/* delete */
-	IBUF_USE_INSERT_DELETE_MARK,	/* insert+delete */
-	IBUF_USE_DELETE,	/* delete+purge */
-	IBUF_USE_ALL		/* insert+delete+purge */
-};
-
-/** Operations that can currently be buffered. */
-extern ulong		innodb_change_buffering;
-
-/** Insert buffer struct */
-struct ibuf_t{
-	Atomic_relaxed<ulint> size;	/*!< current size of the ibuf index
-					tree, in pages */
-	Atomic_relaxed<ulint> max_size;	/*!< recommended maximum size of the
-					ibuf index tree, in pages */
-	ulint		seg_size;	/*!< allocated pages of the file
-					segment containing ibuf header and
-					tree */
-	bool		empty;		/*!< Protected by the page
-					latch of the root page of the
-					insert buffer tree
-					(FSP_IBUF_TREE_ROOT_PAGE_NO). true
-					if and only if the insert
-					buffer tree is empty. */
-	ulint		free_list_len;	/*!< length of the free list */
-	ulint		height;		/*!< tree height */
-	dict_index_t*	index;		/*!< insert buffer index */
-
-	/** number of pages merged */
-	Atomic_counter<ulint> n_merges;
-	Atomic_counter<ulint> n_merged_ops[IBUF_OP_COUNT];
-					/*!< number of operations of each type
-					merged to index pages */
-	Atomic_counter<ulint> n_discarded_ops[IBUF_OP_COUNT];
-					/*!< number of operations of each type
-					discarded without merging due to the
-					tablespace being deleted or the
-					index being dropped */
-};
-
-/** The insert buffer control structure */
-extern ibuf_t		ibuf;
-
-/* The purpose of the insert buffer is to reduce random disk access.
-When we wish to insert a record into a non-unique secondary index and
-the B-tree leaf page where the record belongs to is not in the buffer
-pool, we insert the record into the insert buffer B-tree, indexed by
-(space_id, page_no).  When the page is eventually read into the buffer
-pool, we look up the insert buffer B-tree for any modifications to the
-page, and apply these upon the completion of the read operation.  This
-is called the insert buffer merge. */
-
-/* The insert buffer merge must always succeed.  To guarantee this,
-the insert buffer subsystem keeps track of the free space in pages for
-which it can buffer operations.  Two bits per page in the insert
-buffer bitmap indicate the available space in coarse increments.  The
-free bits in the insert buffer bitmap must never exceed the free space
-on a page.  It is safe to decrement or reset the bits in the bitmap in
-a mini-transaction that is committed before the mini-transaction that
-affects the free space.  It is unsafe to increment the bits in a
-separately committed mini-transaction, because in crash recovery, the
-free bits could momentarily be set too high. */
-
-/******************************************************************//**
-Creates the insert buffer data structure at a database startup.
-@return DB_SUCCESS or failure */
-dberr_t
-ibuf_init_at_db_start(void);
-/*=======================*/
-/*********************************************************************//**
-Updates the max_size value for ibuf. */
-void
-ibuf_max_size_update(
-/*=================*/
-	ulint	new_val);	/*!< in: new value in terms of
-				percentage of the buffer pool size */
-/*********************************************************************//**
-Reads the biggest tablespace id from the high end of the insert buffer
-tree and updates the counter in fil_system. */
-void
-ibuf_update_max_tablespace_id(void);
-/*===============================*/
-/***************************************************************//**
-Starts an insert buffer mini-transaction. */
-UNIV_INLINE
-void
-ibuf_mtr_start(
-/*===========*/
-	mtr_t*	mtr)	/*!< out: mini-transaction */
-	MY_ATTRIBUTE((nonnull));
-/***************************************************************//**
-Commits an insert buffer mini-transaction. */
-UNIV_INLINE
-void
-ibuf_mtr_commit(
-/*============*/
-	mtr_t*	mtr)	/*!< in/out: mini-transaction */
-	MY_ATTRIBUTE((nonnull));
-/************************************************************************//**
-Resets the free bits of the page in the ibuf bitmap. This is done in a
-separate mini-transaction, hence this operation does not restrict
-further work to only ibuf bitmap operations, which would result if the
-latch to the bitmap page were kept.  NOTE: The free bits in the insert
-buffer bitmap must never exceed the free space on a page.  It is safe
-to decrement or reset the bits in the bitmap in a mini-transaction
-that is committed before the mini-transaction that affects the free
-space. */
-void
-ibuf_reset_free_bits(
-/*=================*/
-	buf_block_t*	block);	/*!< in: index page; free bits are set to 0
-				if the index is a non-clustered
-				non-unique, and page level is 0 */
-/************************************************************************//**
-Updates the free bits of an uncompressed page in the ibuf bitmap if
-there is not enough free on the page any more.  This is done in a
-separate mini-transaction, hence this operation does not restrict
-further work to only ibuf bitmap operations, which would result if the
-latch to the bitmap page were kept.  NOTE: The free bits in the insert
-buffer bitmap must never exceed the free space on a page.  It is
-unsafe to increment the bits in a separately committed
-mini-transaction, because in crash recovery, the free bits could
-momentarily be set too high.  It is only safe to use this function for
-decrementing the free bits.  Should more free space become available,
-we must not update the free bits here, because that would break crash
-recovery. */
-UNIV_INLINE
-void
-ibuf_update_free_bits_if_full(
-/*==========================*/
-	buf_block_t*	block,	/*!< in: index page to which we have added new
-				records; the free bits are updated if the
-				index is non-clustered and non-unique and
-				the page level is 0, and the page becomes
-				fuller */
-	ulint		max_ins_size,/*!< in: value of maximum insert size with
-				reorganize before the latest operation
-				performed to the page */
-	ulint		increase);/*!< in: upper limit for the additional space
-				used in the latest operation, if known, or
-				ULINT_UNDEFINED */
-/**********************************************************************//**
-Updates the free bits for an uncompressed page to reflect the present
-state.  Does this in the mtr given, which means that the latching
-order rules virtually prevent any further operations for this OS
-thread until mtr is committed.  NOTE: The free bits in the insert
-buffer bitmap must never exceed the free space on a page.  It is safe
-to set the free bits in the same mini-transaction that updated the
-page. */
-void
-ibuf_update_free_bits_low(
-/*======================*/
-	const buf_block_t*	block,		/*!< in: index page */
-	ulint			max_ins_size,	/*!< in: value of
-						maximum insert size
-						with reorganize before
-						the latest operation
-						performed to the page */
-	mtr_t*			mtr);		/*!< in/out: mtr */
-/**********************************************************************//**
-Updates the free bits for a compressed page to reflect the present
-state.  Does this in the mtr given, which means that the latching
-order rules virtually prevent any further operations for this OS
-thread until mtr is committed.  NOTE: The free bits in the insert
-buffer bitmap must never exceed the free space on a page.  It is safe
-to set the free bits in the same mini-transaction that updated the
-page. */
-void
-ibuf_update_free_bits_zip(
-/*======================*/
-	buf_block_t*	block,	/*!< in/out: index page */
-	mtr_t*		mtr);	/*!< in/out: mtr */
-/**********************************************************************//**
-Updates the free bits for the two pages to reflect the present state.
-Does this in the mtr given, which means that the latching order rules
-virtually prevent any further operations until mtr is committed.
-NOTE: The free bits in the insert buffer bitmap must never exceed the
-free space on a page.  It is safe to set the free bits in the same
-mini-transaction that updated the pages. */
-void
-ibuf_update_free_bits_for_two_pages_low(
-/*====================================*/
-	buf_block_t*	block1,	/*!< in: index page */
-	buf_block_t*	block2,	/*!< in: index page */
-	mtr_t*		mtr);	/*!< in: mtr */
-/**********************************************************************//**
-A basic partial test if an insert to the insert buffer could be possible and
-recommended. */
-UNIV_INLINE
-ibool
-ibuf_should_try(
-/*============*/
-	dict_index_t*	index,			/*!< in: index where to insert */
-	ulint		ignore_sec_unique);	/*!< in: if != 0, we should
-						ignore UNIQUE constraint on
-						a secondary index when we
-						decide */
-/******************************************************************//**
-Returns TRUE if the current OS thread is performing an insert buffer
-routine.
-
-For instance, a read-ahead of non-ibuf pages is forbidden by threads
-that are executing an insert buffer routine.
-@return TRUE if inside an insert buffer routine */
-UNIV_INLINE
-ibool
-ibuf_inside(
-/*========*/
-	const mtr_t*	mtr)	/*!< in: mini-transaction */
-	MY_ATTRIBUTE((warn_unused_result));
-
-/** Checks if a page address is an ibuf bitmap page (level 3 page) address.
-@param[in]	page_id		page id
-@param[in]	zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@return TRUE if a bitmap page */
-inline bool ibuf_bitmap_page(const page_id_t page_id, ulint zip_size)
-{
-	ut_ad(ut_is_2pow(zip_size));
-	ulint size = zip_size ? zip_size : srv_page_size;
-	return (page_id.page_no() & (size - 1)) == FSP_IBUF_BITMAP_OFFSET;
-}
-
-/** Checks if a page is a level 2 or 3 page in the ibuf hierarchy of pages.
-Must not be called when recv_no_ibuf_operations==true.
-@param[in]	page_id		page id
-@param[in]	zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@param[in]	x_latch		FALSE if relaxed check (avoid latching the
-bitmap page)
-@param[in,out]	mtr		mtr which will contain an x-latch to the
-bitmap page if the page is not one of the fixed address ibuf pages, or NULL,
-in which case a new transaction is created.
-@return true if level 2 or level 3 page */
-bool
-ibuf_page_low(
-	const page_id_t		page_id,
-	ulint			zip_size,
-#ifdef UNIV_DEBUG
-	bool			x_latch,
-#endif /* UNIV_DEBUG */
-	mtr_t*			mtr)
-	MY_ATTRIBUTE((warn_unused_result));
-
-#ifdef UNIV_DEBUG
-/** Checks if a page is a level 2 or 3 page in the ibuf hierarchy of pages.
-Must not be called when recv_no_ibuf_operations==true.
-@param[in]	page_id		tablespace/page identifier
-@param[in]	zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@param[in,out]	mtr		mini-transaction or NULL
-@return TRUE if level 2 or level 3 page */
-# define ibuf_page(page_id, zip_size, mtr)	\
-	ibuf_page_low(page_id, zip_size, true, mtr)
-
-#else /* UNIV_DEBUG */
-
-/** Checks if a page is a level 2 or 3 page in the ibuf hierarchy of pages.
-Must not be called when recv_no_ibuf_operations==true.
-@param[in]	page_id		tablespace/page identifier
-@param[in]	zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@param[in,out]	mtr		mini-transaction or NULL
-@return TRUE if level 2 or level 3 page */
-# define ibuf_page(page_id, zip_size, mtr)	\
-	ibuf_page_low(page_id, zip_size, mtr)
-
-#endif /* UNIV_DEBUG */
-/***********************************************************************//**
-Frees excess pages from the ibuf free list. This function is called when an OS
-thread calls fsp services to allocate a new file segment, or a new page to a
-file segment, and the thread did not own the fsp latch before this call. */
-void
-ibuf_free_excess_pages(void);
-/*========================*/
-
-/** Buffer an operation in the change buffer, instead of applying it
-directly to the file page, if this is possible. Does not do it if the index
-is clustered or unique.
-@param[in]	op		operation type
-@param[in]	entry		index entry to insert
-@param[in,out]	index		index where to insert
-@param[in]	page_id		page id where to insert
-@param[in]	zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@param[in,out]	thr		query thread
-@return true if success */
-bool
-ibuf_insert(
-	ibuf_op_t		op,
-	const dtuple_t*		entry,
-	dict_index_t*		index,
-	const page_id_t		page_id,
-	ulint			zip_size,
-	que_thr_t*		thr);
-
-/** Check whether buffered changes exist for a page.
-@param[in]	id		page identifier
-@param[in]	zip_size	ROW_FORMAT=COMPRESSED page size, or 0
-@return whether buffered changes exist */
-bool ibuf_page_exists(const page_id_t id, ulint zip_size);
-
-/** When an index page is read from a disk to the buffer pool, this function
-applies any buffered operations to the page and deletes the entries from the
-insert buffer. If the page is not read, but created in the buffer pool, this
-function deletes its buffered entries from the insert buffer; there can
-exist entries for such a page if the page belonged to an index which
-subsequently was dropped.
-@param block    X-latched page to try to apply changes to, or NULL to discard
-@param page_id  page identifier
-@param zip_size ROW_FORMAT=COMPRESSED page size, or 0
-@return error code */
-dberr_t ibuf_merge_or_delete_for_page(buf_block_t *block,
-                                      const page_id_t page_id,
-                                      ulint zip_size);
-
-/** Delete all change buffer entries for a tablespace,
-in DISCARD TABLESPACE, IMPORT TABLESPACE, or read-ahead.
-@param[in]	space		missing or to-be-discarded tablespace */
-void ibuf_delete_for_discarded_space(uint32_t space);
-
-/** Contract the change buffer by reading pages to the buffer pool.
-@return a lower limit for the combined size in bytes of entries which
-will be merged from ibuf trees to the pages read
-@retval 0 if ibuf.empty */
-ulint ibuf_contract();
-
-/** Contracts insert buffer trees by reading pages referring to space_id
-to the buffer pool.
-@returns number of pages merged.*/
-ulint
-ibuf_merge_space(
-/*=============*/
-	ulint	space);	/*!< in: space id */
-
-/******************************************************************//**
-Looks if the insert buffer is empty.
-@return true if empty */
-bool
-ibuf_is_empty(void);
-/*===============*/
-/******************************************************************//**
-Prints info of ibuf. */
-void
-ibuf_print(
-/*=======*/
-	FILE*	file);	/*!< in: file where to print */
-/********************************************************************
-Read the first two bytes from a record's fourth field (counter field in new
-records; something else in older records).
-@return "counter" field, or ULINT_UNDEFINED if for some reason it can't be read */
-ulint
-ibuf_rec_get_counter(
-/*=================*/
-	const rec_t*	rec);	/*!< in: ibuf record */
-/******************************************************************//**
-Closes insert buffer and frees the data structures. */
-void
-ibuf_close(void);
-/*============*/
-
-/** Check the insert buffer bitmaps on IMPORT TABLESPACE.
-@param[in]	trx	transaction
-@param[in,out]	space	tablespace being imported
-@return DB_SUCCESS or error code */
-dberr_t ibuf_check_bitmap_on_import(const trx_t* trx, fil_space_t* space)
-	MY_ATTRIBUTE((nonnull, warn_unused_result));
-
-/** Update free bits and buffered bits for bulk loaded page.
-@param block   secondary index leaf page
-@param mtr     mini-transaction
-@param reset   whether the page is full */
-void ibuf_set_bitmap_for_bulk_load(buf_block_t *block, mtr_t *mtr, bool reset);
-
-#define IBUF_HEADER_PAGE_NO	FSP_IBUF_HEADER_PAGE_NO
-#define IBUF_TREE_ROOT_PAGE_NO	FSP_IBUF_TREE_ROOT_PAGE_NO
-
-/* The ibuf header page currently contains only the file segment header
-for the file segment from which the pages for the ibuf tree are allocated */
-#define IBUF_HEADER		PAGE_DATA
-#define	IBUF_TREE_SEG_HEADER	0	/* fseg header for ibuf tree */
-
-/* The insert buffer tree itself is always located in space 0. */
-#define IBUF_SPACE_ID		static_cast<ulint>(0)
-
-#include "ibuf0ibuf.inl"
-
-#endif
+#include "db0err.h"
+
+/* The purpose of the change buffer was to reduce random disk access.
+When we wished to
+(1) insert a record into a non-unique secondary index,
+(2) delete-mark a secondary index record,
+(3) delete a secondary index record as part of purge (but not ROLLBACK),
+and the B-tree leaf page where the record belongs to is not in the buffer
+pool, we inserted a record into the change buffer B-tree, indexed by
+the page identifier. When the page was eventually read into the buffer
+pool, we looked up the change buffer B-tree for any modifications to the
+page, applied these upon the completion of the read operation. This
+was called the insert buffer merge.
+
+There was a hash index of the change buffer B-tree, implemented as the
+"change buffer bitmap". Bits in these bitmap pages indicated how full
+the page roughly was, and whether any records for the page identifier
+exist in the change buffer. The "free" bits had to be updated as part of
+operations that modified secondary index leaf pages.
+
+Because the change buffer has been removed, we will no longer update
+any change buffer bitmap pages. Instead, on database startup, we will
+check if an upgrade needs to be performed, and apply any buffered
+changes if that is the case. Finally, the change buffer will be
+transformed to a format that will not be recognized by earlier
+versions of MariaDB Server, to prevent downgrades from causing
+corruption (due to the removed updates of the bitmap pages) when the
+change buffer might be enabled. */
+
+/** Check if ibuf_upgrade() is needed as part of server startup.
+@return error code
+@retval DB_SUCCESS if no upgrade is needed
+@retval DB_FAIL    if the change buffer is not empty (need ibuf_upgrade()) */
+dberr_t ibuf_upgrade_needed();
+
+/** Upgrade the change buffer after all redo log has been applied. */
+dberr_t ibuf_upgrade();
diff --git a/storage/innobase/include/ibuf0ibuf.inl b/storage/innobase/include/ibuf0ibuf.inl
deleted file mode 100644
index 12aa1ca6837..00000000000
--- a/storage/innobase/include/ibuf0ibuf.inl
+++ /dev/null
@@ -1,282 +0,0 @@
-/*****************************************************************************
-
-Copyright (c) 1997, 2015, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2021, MariaDB Corporation.
-
-This program is free software; you can redistribute it and/or modify it under
-the terms of the GNU General Public License as published by the Free Software
-Foundation; version 2 of the License.
-
-This program is distributed in the hope that it will be useful, but WITHOUT
-ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
-FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License along with
-this program; if not, write to the Free Software Foundation, Inc.,
-51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA
-
-*****************************************************************************/
-
-/**************************************************//**
-@file include/ibuf0ibuf.ic
-Insert buffer
-
-Created 7/19/1997 Heikki Tuuri
-*******************************************************/
-
-#include "page0page.h"
-#include "page0zip.h"
-#include "fsp0types.h"
-#include "buf0lru.h"
-
-/** An index page must contain at least srv_page_size /
-IBUF_PAGE_SIZE_PER_FREE_SPACE bytes of free space for ibuf to try to
-buffer inserts to this page.  If there is this much of free space, the
-corresponding bits are set in the ibuf bitmap. */
-#define IBUF_PAGE_SIZE_PER_FREE_SPACE	32
-
-/***************************************************************//**
-Starts an insert buffer mini-transaction. */
-UNIV_INLINE
-void
-ibuf_mtr_start(
-/*===========*/
-	mtr_t*	mtr)	/*!< out: mini-transaction */
-{
-	mtr_start(mtr);
-	mtr->enter_ibuf();
-
-	if (high_level_read_only || srv_read_only_mode) {
-		mtr_set_log_mode(mtr, MTR_LOG_NO_REDO);
-	}
-
-}
-/***************************************************************//**
-Commits an insert buffer mini-transaction. */
-UNIV_INLINE
-void
-ibuf_mtr_commit(
-/*============*/
-	mtr_t*	mtr)	/*!< in/out: mini-transaction */
-{
-	ut_ad(mtr->is_inside_ibuf());
-	ut_d(mtr->exit_ibuf());
-
-	mtr_commit(mtr);
-}
-
-/************************************************************************//**
-Sets the free bit of the page in the ibuf bitmap. This is done in a separate
-mini-transaction, hence this operation does not restrict further work to only
-ibuf bitmap operations, which would result if the latch to the bitmap page
-were kept. */
-void
-ibuf_set_free_bits_func(
-/*====================*/
-	buf_block_t*	block,	/*!< in: index page of a non-clustered index;
-				free bit is reset if page level is 0 */
-#ifdef UNIV_IBUF_DEBUG
-	ulint		max_val,/*!< in: ULINT_UNDEFINED or a maximum
-				value which the bits must have before
-				setting; this is for debugging */
-#endif /* UNIV_IBUF_DEBUG */
-	ulint		val);	/*!< in: value to set: < 4 */
-#ifdef UNIV_IBUF_DEBUG
-# define ibuf_set_free_bits(b,v,max) ibuf_set_free_bits_func(b,max,v)
-#else /* UNIV_IBUF_DEBUG */
-# define ibuf_set_free_bits(b,v,max) ibuf_set_free_bits_func(b,v)
-#endif /* UNIV_IBUF_DEBUG */
-
-/**********************************************************************//**
-A basic partial test if an insert to the insert buffer could be possible and
-recommended. */
-UNIV_INLINE
-ibool
-ibuf_should_try(
-/*============*/
-	dict_index_t*	index,			/*!< in: index where to insert */
-	ulint		ignore_sec_unique)	/*!< in: if != 0, we should
-						ignore UNIQUE constraint on
-						a secondary index when we
-						decide */
-{
-  if (!innodb_change_buffering || !ibuf.max_size || index->is_clust() ||
-      index->is_spatial())
-    return false;
-  if (!ignore_sec_unique && index->is_unique())
-    return false;
-  if (index->table->quiesce != QUIESCE_NONE)
-    return false;
-  for (unsigned i= 0; i < index->n_fields; i++)
-    if (index->fields[i].descending)
-      return false;
-  return true;
-}
-
-/******************************************************************//**
-Returns TRUE if the current OS thread is performing an insert buffer
-routine.
-
-For instance, a read-ahead of non-ibuf pages is forbidden by threads
-that are executing an insert buffer routine.
-@return TRUE if inside an insert buffer routine */
-UNIV_INLINE
-ibool
-ibuf_inside(
-/*========*/
-	const mtr_t*	mtr)	/*!< in: mini-transaction */
-{
-	return(mtr->is_inside_ibuf());
-}
-
-/** Translates the free space on a page to a value in the ibuf bitmap.
-@param[in]	page_size	page size in bytes
-@param[in]	max_ins_size	maximum insert size after reorganize for
-the page
-@return value for ibuf bitmap bits */
-UNIV_INLINE
-ulint
-ibuf_index_page_calc_free_bits(
-	ulint	page_size,
-	ulint	max_ins_size)
-{
-	ulint	n;
-	ut_ad(ut_is_2pow(page_size));
-	ut_ad(page_size > IBUF_PAGE_SIZE_PER_FREE_SPACE);
-
-	n = max_ins_size / (page_size / IBUF_PAGE_SIZE_PER_FREE_SPACE);
-
-	if (n == 3) {
-		n = 2;
-	}
-
-	if (n > 3) {
-		n = 3;
-	}
-
-	return(n);
-}
-
-/*********************************************************************//**
-Translates the free space on a compressed page to a value in the ibuf bitmap.
-@return value for ibuf bitmap bits */
-UNIV_INLINE
-ulint
-ibuf_index_page_calc_free_zip(
-/*==========================*/
-	const buf_block_t*	block)	/*!< in: buffer block */
-{
-	ulint			max_ins_size;
-	const page_zip_des_t*	page_zip;
-	lint			zip_max_ins;
-
-	ut_ad(block->page.zip.data);
-
-	/* Consider the maximum insert size on the uncompressed page
-	without reorganizing the page. We must not assume anything
-	about the compression ratio. If zip_max_ins > max_ins_size and
-	there is 1/4 garbage on the page, recompression after the
-	reorganize could fail, in theory. So, let us guarantee that
-	merging a buffered insert to a compressed page will always
-	succeed without reorganizing or recompressing the page, just
-	by using the page modification log. */
-	max_ins_size = page_get_max_insert_size(
-		buf_block_get_frame(block), 1);
-
-	page_zip = buf_block_get_page_zip(block);
-	zip_max_ins = page_zip_max_ins_size(page_zip,
-					    FALSE/* not clustered */);
-
-	if (zip_max_ins < 0) {
-		return(0);
-	} else if (max_ins_size > (ulint) zip_max_ins) {
-		max_ins_size = (ulint) zip_max_ins;
-	}
-
-	return(ibuf_index_page_calc_free_bits(block->physical_size(),
-					      max_ins_size));
-}
-
-/*********************************************************************//**
-Translates the free space on a page to a value in the ibuf bitmap.
-@return value for ibuf bitmap bits */
-UNIV_INLINE
-ulint
-ibuf_index_page_calc_free(
-/*======================*/
-	const buf_block_t*	block)	/*!< in: buffer block */
-{
-	if (!block->page.zip.data) {
-		ulint	max_ins_size;
-
-		max_ins_size = page_get_max_insert_size_after_reorganize(
-			buf_block_get_frame(block), 1);
-
-		return(ibuf_index_page_calc_free_bits(
-				block->physical_size(), max_ins_size));
-	} else {
-		return(ibuf_index_page_calc_free_zip(block));
-	}
-}
-
-/************************************************************************//**
-Updates the free bits of an uncompressed page in the ibuf bitmap if
-there is not enough free on the page any more.  This is done in a
-separate mini-transaction, hence this operation does not restrict
-further work to only ibuf bitmap operations, which would result if the
-latch to the bitmap page were kept.  NOTE: The free bits in the insert
-buffer bitmap must never exceed the free space on a page.  It is
-unsafe to increment the bits in a separately committed
-mini-transaction, because in crash recovery, the free bits could
-momentarily be set too high.  It is only safe to use this function for
-decrementing the free bits.  Should more free space become available,
-we must not update the free bits here, because that would break crash
-recovery. */
-UNIV_INLINE
-void
-ibuf_update_free_bits_if_full(
-/*==========================*/
-	buf_block_t*	block,	/*!< in: index page to which we have added new
-				records; the free bits are updated if the
-				index is non-clustered and non-unique and
-				the page level is 0, and the page becomes
-				fuller */
-	ulint		max_ins_size,/*!< in: value of maximum insert size with
-				reorganize before the latest operation
-				performed to the page */
-	ulint		increase)/*!< in: upper limit for the additional space
-				used in the latest operation, if known, or
-				ULINT_UNDEFINED */
-{
-	ulint	before;
-	ulint	after;
-
-	ut_ad(buf_block_get_page_zip(block) == NULL);
-
-	before = ibuf_index_page_calc_free_bits(
-		srv_page_size, max_ins_size);
-
-	if (max_ins_size >= increase) {
-		compile_time_assert(ULINT32_UNDEFINED > UNIV_PAGE_SIZE_MAX);
-		after = ibuf_index_page_calc_free_bits(
-			srv_page_size, max_ins_size - increase);
-#ifdef UNIV_IBUF_DEBUG
-		ut_a(after <= ibuf_index_page_calc_free(block));
-#endif
-	} else {
-		after = ibuf_index_page_calc_free(block);
-	}
-
-	if (after == 0) {
-		/* We move the page to the front of the buffer pool LRU list:
-		the purpose of this is to prevent those pages to which we
-		cannot make inserts using the insert buffer from slipping
-		out of the buffer pool */
-
-		buf_page_make_young(&block->page);
-	}
-
-	if (before > after) {
-		ibuf_set_free_bits(block, after, before);
-	}
-}
diff --git a/storage/innobase/include/log0recv.h b/storage/innobase/include/log0recv.h
index e787d81e8c2..c0b79f1a76d 100644
--- a/storage/innobase/include/log0recv.h
+++ b/storage/innobase/include/log0recv.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1997, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -417,16 +417,6 @@ public:
 /** The recovery system */
 extern recv_sys_t	recv_sys;
 
-/** If the following is TRUE, the buffer pool file pages must be invalidated
-after recovery and no ibuf operations are allowed; this will be set if
-recv_sys.pages becomes too full, and log records must be merged
-to file pages already before the recovery is finished: in this case no
-ibuf operations are allowed, as they could modify the pages read in the
-buffer pool before the pages have been recovered to the up-to-date state.
-
-TRUE means that recovery is running and no operations on the log files
-are allowed yet: the variable name is misleading. */
-extern bool		recv_no_ibuf_operations;
 /** TRUE when recv_init_crash_recovery() has been called. */
 extern bool		recv_needed_recovery;
 #ifdef UNIV_DEBUG
diff --git a/storage/innobase/include/mtr0mtr.h b/storage/innobase/include/mtr0mtr.h
index abc1f65e692..debc3a3fc9c 100644
--- a/storage/innobase/include/mtr0mtr.h
+++ b/storage/innobase/include/mtr0mtr.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1995, 2017, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2013, 2022, MariaDB Corporation.
+Copyright (c) 2013, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -381,15 +381,6 @@ public:
   @retval 0 if the transaction only modified temporary tablespaces */
   lsn_t commit_lsn() const { ut_ad(has_committed()); return m_commit_lsn; }
 
-  /** Note that we are inside the change buffer code. */
-  void enter_ibuf() { m_inside_ibuf= true; }
-
-  /** Note that we have exited from the change buffer code. */
-  void exit_ibuf() { m_inside_ibuf= false; }
-
-  /** @return true if we are inside the change buffer code */
-  bool is_inside_ibuf() const { return m_inside_ibuf; }
-
   /** Note that some pages have been freed */
   void set_trim_pages() { m_trim_pages= true; }
 
@@ -792,10 +783,6 @@ private:
   /** whether log_sys.latch is locked exclusively */
   uint16_t m_latch_ex:1;
 
-  /** whether change buffer is latched; only needed in non-debug builds
-  to suppress some read-ahead operations, @see ibuf_inside() */
-  uint16_t m_inside_ibuf:1;
-
   /** whether the pages has been trimmed */
   uint16_t m_trim_pages:1;
 
diff --git a/storage/innobase/include/page0cur.h b/storage/innobase/include/page0cur.h
index 28aa30565e4..279138acd79 100644
--- a/storage/innobase/include/page0cur.h
+++ b/storage/innobase/include/page0cur.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1994, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2018, 2022, MariaDB Corporation.
+Copyright (c) 2018, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -117,11 +117,6 @@ succeed, i.e., enough space available, NULL otherwise. The cursor stays at
 the same logical position, but the physical position may change if it is
 pointing to a compressed page that was reorganized.
 
-IMPORTANT: The caller will have to update IBUF_BITMAP_FREE
-if this is a compressed leaf page in a secondary index.
-This has to be done either within the same mini-transaction,
-or by invoking ibuf_reset_free_bits() before mtr_commit().
-
 @return pointer to record if succeed, NULL otherwise */
 UNIV_INLINE
 rec_t*
@@ -151,11 +146,6 @@ page_cur_insert_rec_low(
 Inserts a record next to page cursor on a compressed and uncompressed
 page.
 
-IMPORTANT: The caller will have to update IBUF_BITMAP_FREE
-if this is a compressed leaf page in a secondary index.
-This has to be done either within the same mini-transaction,
-or by invoking ibuf_reset_free_bits() before mtr_commit().
-
 @return pointer to inserted record
 @return nullptr on failure */
 rec_t*
diff --git a/storage/innobase/include/page0cur.inl b/storage/innobase/include/page0cur.inl
index 7c4eafa266a..a73c31a7bff 100644
--- a/storage/innobase/include/page0cur.inl
+++ b/storage/innobase/include/page0cur.inl
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1994, 2014, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2015, 2022, MariaDB Corporation.
+Copyright (c) 2015, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -155,11 +155,6 @@ succeed, i.e., enough space available, NULL otherwise. The cursor stays at
 the same logical position, but the physical position may change if it is
 pointing to a compressed page that was reorganized.
 
-IMPORTANT: The caller will have to update IBUF_BITMAP_FREE
-if this is a compressed leaf page in a secondary index.
-This has to be done either within the same mini-transaction,
-or by invoking ibuf_reset_free_bits() before mtr_commit().
-
 @return pointer to record if succeed, NULL otherwise */
 UNIV_INLINE
 rec_t*
diff --git a/storage/innobase/include/page0page.h b/storage/innobase/include/page0page.h
index 2978656b508..38373f6bb19 100644
--- a/storage/innobase/include/page0page.h
+++ b/storage/innobase/include/page0page.h
@@ -1,6 +1,6 @@
 /*****************************************************************************
 Copyright (c) 1994, 2019, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2013, 2022, MariaDB Corporation.
+Copyright (c) 2013, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -95,7 +95,7 @@ this byte can be garbage. */
 				direction */
 #define	PAGE_N_RECS	 16	/* number of user records on the page */
 /** The largest DB_TRX_ID that may have modified a record on the page;
-Defined only in secondary index leaf pages and in change buffer leaf pages.
+Defined only in secondary index leaf pages.
 Otherwise written as 0. @see PAGE_ROOT_AUTO_INC */
 #define PAGE_MAX_TRX_ID	 18
 /** The AUTO_INCREMENT value (on persistent clustered index root pages). */
@@ -901,11 +901,6 @@ MY_ATTRIBUTE((nonnull, warn_unused_result))
 Differs from page_copy_rec_list_end, because this function does not
 touch the lock table and max trx id on page or compress the page.
 
-IMPORTANT: The caller will have to update IBUF_BITMAP_FREE
-if new_block is a compressed leaf page in a secondary index.
-This has to be done either within the same mini-transaction,
-or by invoking ibuf_reset_free_bits() before mtr_t::commit().
-
 @return error code */
 dberr_t
 page_copy_rec_list_end_no_locks(
@@ -920,11 +915,6 @@ Copies records from page to new_page, from the given record onward,
 including that record. Infimum and supremum records are not copied.
 The records are copied to the start of the record list on new_page.
 
-IMPORTANT: The caller will have to update IBUF_BITMAP_FREE
-if new_block is a compressed leaf page in a secondary index.
-This has to be done either within the same mini-transaction,
-or by invoking ibuf_reset_free_bits() before mtr_t::commit().
-
 @return pointer to the original successor of the infimum record on new_block
 @retval nullptr on ROW_FORMAT=COMPRESSED page overflow */
 rec_t*
@@ -942,11 +932,6 @@ Copies records from page to new_page, up to the given record, NOT
 including that record. Infimum and supremum records are not copied.
 The records are copied to the end of the record list on new_page.
 
-IMPORTANT: The caller will have to update IBUF_BITMAP_FREE
-if new_block is a compressed leaf page in a secondary index.
-This has to be done either within the same mini-transaction,
-or by invoking ibuf_reset_free_bits() before mtr_commit().
-
 @return pointer to the original predecessor of the supremum record on new_block
 @retval nullptr on ROW_FORMAT=COMPRESSED page overflow */
 rec_t*
diff --git a/storage/innobase/include/page0zip.h b/storage/innobase/include/page0zip.h
index 4332990619e..501ef31a8f9 100644
--- a/storage/innobase/include/page0zip.h
+++ b/storage/innobase/include/page0zip.h
@@ -2,7 +2,7 @@
 
 Copyright (c) 2005, 2016, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2012, Facebook Inc.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -213,9 +213,9 @@ page_zip_max_ins_size(
 
 /**********************************************************************//**
 Determine if enough space is available in the modification log.
-@return TRUE if page_zip_write_rec() will succeed */
+@return true if page_zip_write_rec() will succeed */
 UNIV_INLINE
-ibool
+bool
 page_zip_available(
 /*===============*/
 	const page_zip_des_t*	page_zip,/*!< in: compressed page */
@@ -323,10 +323,6 @@ Reorganize and compress a page.  This is a low-level operation for
 compressed pages, to be used when page_zip_compress() fails.
 On success, redo log will be written.
 The function btr_page_reorganize() should be preferred whenever possible.
-IMPORTANT: if page_zip_reorganize() is invoked on a leaf page of a
-non-clustered index, the caller must update the insert buffer free
-bits in the same mini-transaction in such a way that the modification
-will be redo-logged.
 @return error code
 @retval DB_FAIL on overflow; the block_zip will be left intact */
 dberr_t
diff --git a/storage/innobase/include/page0zip.inl b/storage/innobase/include/page0zip.inl
index afc877c3720..edcd4ab48fa 100644
--- a/storage/innobase/include/page0zip.inl
+++ b/storage/innobase/include/page0zip.inl
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2005, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -269,7 +269,7 @@ page_zip_max_ins_size(
 Determine if enough space is available in the modification log.
 @return TRUE if enough space is available */
 UNIV_INLINE
-ibool
+bool
 page_zip_available(
 /*===============*/
 	const page_zip_des_t*	page_zip,/*!< in: compressed page */
diff --git a/storage/innobase/include/rem0rec.inl b/storage/innobase/include/rem0rec.inl
index 46c209cbdec..da7337a3b82 100644
--- a/storage/innobase/include/rem0rec.inl
+++ b/storage/innobase/include/rem0rec.inl
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1994, 2019, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -1095,9 +1095,7 @@ rec_get_converted_size(
 
 	ut_ad(dtuple_check_typed(dtuple));
 #ifdef UNIV_DEBUG
-	if (dict_index_is_ibuf(index)) {
-		ut_ad(dtuple->n_fields > 1);
-	} else if ((dtuple_get_info_bits(dtuple) & REC_NEW_STATUS_MASK)
+	if ((dtuple_get_info_bits(dtuple) & REC_NEW_STATUS_MASK)
 		   == REC_STATUS_NODE_PTR) {
 		ut_ad(dtuple->n_fields - 1
 		      == dict_index_get_n_unique_in_tree_nonleaf(index));
diff --git a/storage/innobase/include/row0purge.h b/storage/innobase/include/row0purge.h
index b1390fd1ef1..686bbaa7384 100644
--- a/storage/innobase/include/row0purge.h
+++ b/storage/innobase/include/row0purge.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1997, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2019, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -37,39 +37,6 @@ Created 3/14/1997 Heikki Tuuri
 #include <queue>
 
 class MDL_ticket;
-/** Determines if it is possible to remove a secondary index entry.
-Removal is possible if the secondary index entry does not refer to any
-not delete marked version of a clustered index record where DB_TRX_ID
-is newer than the purge view.
-
-NOTE: This function should only be called by the purge thread, only
-while holding a latch on the leaf page of the secondary index entry
-(or keeping the buffer pool watch on the page).  It is possible that
-this function first returns true and then false, if a user transaction
-inserts a record that the secondary index entry would refer to.
-However, in that case, the user transaction would also re-insert the
-secondary index entry after purge has removed it and released the leaf
-page latch.
-@param[in,out]	node		row purge node
-@param[in]	index		secondary index
-@param[in]	entry		secondary index entry
-@param[in,out]	sec_pcur	secondary index cursor or NULL
-				if it is called for purge buffering
-				operation.
-@param[in,out]	sec_mtr		mini-transaction which holds
-				secondary index entry or NULL if it is
-				called for purge buffering operation.
-@param[in]	is_tree		true=pessimistic purge,
-				false=optimistic (leaf-page only)
-@return true if the secondary index record can be purged */
-bool
-row_purge_poss_sec(
-	purge_node_t*	node,
-	dict_index_t*	index,
-	const dtuple_t*	entry,
-	btr_pcur_t*	sec_pcur=NULL,
-	mtr_t*		sec_mtr=NULL,
-	bool		is_tree=false);
 
 /***************************************************************
 Does the purge operation.
diff --git a/storage/innobase/include/row0row.h b/storage/innobase/include/row0row.h
index a1350740e2a..25cadf272dd 100644
--- a/storage/innobase/include/row0row.h
+++ b/storage/innobase/include/row0row.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2016, 2022, MariaDB Corporation.
+Copyright (c) 2016, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -28,7 +28,6 @@ Created 4/20/1996 Heikki Tuuri
 #define row0row_h
 
 #include "que0types.h"
-#include "ibuf0ibuf.h"
 #include "trx0types.h"
 #include "mtr0mtr.h"
 #include "rem0types.h"
@@ -344,31 +343,19 @@ row_parse_int(
 	ulint		mtype,
 	bool		unsigned_type);
 
-/** Result of row_search_index_entry */
-enum row_search_result {
-	ROW_FOUND = 0,		/*!< the record was found */
-	ROW_NOT_FOUND,		/*!< record not found */
-	ROW_BUFFERED,		/*!< one of BTR_INSERT, BTR_DELETE, or
-				BTR_DELETE_MARK was specified, the
-				secondary index leaf page was not in
-				the buffer pool, and the operation was
-				enqueued in the insert/delete buffer */
-	ROW_NOT_DELETED_REF	/*!< BTR_DELETE was specified, and
-				row_purge_poss_sec() failed */
-};
-
 /***************************************************************//**
 Searches an index record.
-@return whether the record was found or buffered */
-enum row_search_result
+@return whether the record was found */
+bool
 row_search_index_entry(
 /*===================*/
 	const dtuple_t*	entry,	/*!< in: index entry */
 	btr_latch_mode	mode,	/*!< in: BTR_MODIFY_LEAF, ... */
 	btr_pcur_t*	pcur,	/*!< in/out: persistent cursor, which must
 				be closed by the caller */
+	que_thr_t*	thr,	/*!< in/out: query thread */
 	mtr_t*		mtr)	/*!< in: mtr */
-	MY_ATTRIBUTE((nonnull, warn_unused_result));
+	MY_ATTRIBUTE((nonnull(1,3,5), warn_unused_result));
 
 #define ROW_COPY_DATA		1
 #define ROW_COPY_POINTERS	2
@@ -398,22 +385,17 @@ row_raw_format(
 						in bytes */
 	MY_ATTRIBUTE((nonnull, warn_unused_result));
 
+#include "dict0mem.h"
+
 /** Prepare to start a mini-transaction to modify an index.
 @param[in,out]	mtr		mini-transaction
-@param[in,out]	index		possibly secondary index
-@param[in]	pessimistic	whether this is a pessimistic operation */
-inline
-void
-row_mtr_start(mtr_t* mtr, dict_index_t* index, bool pessimistic)
+@param[in,out]	index		possibly secondary index */
+inline void row_mtr_start(mtr_t* mtr, dict_index_t* index)
 {
 	mtr->start();
 
 	switch (index->table->space_id) {
-	case IBUF_SPACE_ID:
-		if (pessimistic
-		    && !(index->type & (DICT_UNIQUE | DICT_SPATIAL))) {
-			ibuf_free_excess_pages();
-		}
+	case 0:
 		break;
 	case SRV_TMP_SPACE_ID:
 		mtr->set_log_mode(MTR_LOG_NO_REDO);
diff --git a/storage/innobase/include/srv0mon.h b/storage/innobase/include/srv0mon.h
index 51f3049b81a..4672ce00a36 100644
--- a/storage/innobase/include/srv0mon.h
+++ b/storage/innobase/include/srv0mon.h
@@ -2,7 +2,7 @@
 
 Copyright (c) 2010, 2015, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2012, Facebook Inc.
-Copyright (c) 2013, 2022, MariaDB Corporation.
+Copyright (c) 2013, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it
 under the terms of the GNU General Public License as published by the
@@ -228,12 +228,8 @@ enum monitor_id_t {
 	MONITOR_MODULE_BUF_PAGE,
 	MONITOR_INDEX_LEAF_PAGE_READ,
 	MONITOR_INDEX_NON_LEAF_PAGE_READ,
-	MONITOR_INDEX_IBUF_LEAF_PAGE_READ,
-	MONITOR_INDEX_IBUF_NON_LEAF_PAGE_READ,
 	MONITOR_UNDO_LOG_PAGE_READ,
 	MONITOR_INODE_PAGE_READ,
-	MONITOR_IBUF_FREELIST_PAGE_READ,
-	MONITOR_IBUF_BITMAP_PAGE_READ,
 	MONITOR_SYSTEM_PAGE_READ,
 	MONITOR_TRX_SYSTEM_PAGE_READ,
 	MONITOR_FSP_HDR_PAGE_READ,
@@ -244,12 +240,8 @@ enum monitor_id_t {
 	MONITOR_OTHER_PAGE_READ,
 	MONITOR_INDEX_LEAF_PAGE_WRITTEN,
 	MONITOR_INDEX_NON_LEAF_PAGE_WRITTEN,
-	MONITOR_INDEX_IBUF_LEAF_PAGE_WRITTEN,
-	MONITOR_INDEX_IBUF_NON_LEAF_PAGE_WRITTEN,
 	MONITOR_UNDO_LOG_PAGE_WRITTEN,
 	MONITOR_INODE_PAGE_WRITTEN,
-	MONITOR_IBUF_FREELIST_PAGE_WRITTEN,
-	MONITOR_IBUF_BITMAP_PAGE_WRITTEN,
 	MONITOR_SYSTEM_PAGE_WRITTEN,
 	MONITOR_TRX_SYSTEM_PAGE_WRITTEN,
 	MONITOR_FSP_HDR_PAGE_WRITTEN,
@@ -347,17 +339,6 @@ enum monitor_id_t {
 	MONITOR_MODULE_FIL_SYSTEM,
 	MONITOR_OVLD_N_FILE_OPENED,
 
-	/* InnoDB Change Buffer related counters */
-	MONITOR_MODULE_IBUF_SYSTEM,
-	MONITOR_OVLD_IBUF_MERGE_INSERT,
-	MONITOR_OVLD_IBUF_MERGE_DELETE,
-	MONITOR_OVLD_IBUF_MERGE_PURGE,
-	MONITOR_OVLD_IBUF_MERGE_DISCARD_INSERT,
-	MONITOR_OVLD_IBUF_MERGE_DISCARD_DELETE,
-	MONITOR_OVLD_IBUF_MERGE_DISCARD_PURGE,
-	MONITOR_OVLD_IBUF_MERGES,
-	MONITOR_OVLD_IBUF_SIZE,
-
 	/* Counters for server operations */
 	MONITOR_MODULE_SERVER,
 	MONITOR_MASTER_THREAD_SLEEP,
diff --git a/storage/innobase/include/srv0srv.h b/storage/innobase/include/srv0srv.h
index 606d94818cf..f94c52c2d97 100644
--- a/storage/innobase/include/srv0srv.h
+++ b/storage/innobase/include/srv0srv.h
@@ -170,9 +170,9 @@ extern char*	srv_data_home;
 recovery and open all tables in RO mode instead of RW mode. We don't
 sync the max trx id to disk either. */
 extern my_bool	srv_read_only_mode;
-/** Set if InnoDB operates in read-only mode or innodb-force-recovery
-is greater than SRV_FORCE_NO_IBUF_MERGE. */
-extern my_bool	high_level_read_only;
+/** Set if innodb_read_only is set or innodb_force_recovery
+is SRV_FORCE_NO_UNDO_LOG_SCAN or greater. */
+extern bool high_level_read_only;
 /** store to its own file each table created by an user; data
 dictionary tables are in the system tablespace 0 */
 extern my_bool	srv_file_per_table;
@@ -585,11 +585,6 @@ void srv_monitor_task(void*);
 void srv_master_callback(void*);
 
 
-/**
-Complete the shutdown tasks such as background DROP TABLE,
-and optionally change buffer merge (on innodb_fast_shutdown=0). */
-void srv_shutdown(bool ibuf_merge);
-
 } /* extern "C" */
 
 #ifdef UNIV_DEBUG
diff --git a/storage/innobase/include/sux_lock.h b/storage/innobase/include/sux_lock.h
index 2c0167ac651..7a7f93b6787 100644
--- a/storage/innobase/include/sux_lock.h
+++ b/storage/innobase/include/sux_lock.h
@@ -1,6 +1,6 @@
 /*****************************************************************************
 
-Copyright (c) 2020, 2022, MariaDB Corporation.
+Copyright (c) 2020, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -149,7 +149,7 @@ private:
 #endif
 
 public:
-  /** In crash recovery or the change buffer, claim the ownership
+  /** In crash recovery, claim the ownership
   of the exclusive block lock to the current thread */
   void claim_ownership() { set_new_owner(pthread_self()); }
 
diff --git a/storage/innobase/include/trx0trx.h b/storage/innobase/include/trx0trx.h
index 0450be89cfb..a571de04f2f 100644
--- a/storage/innobase/include/trx0trx.h
+++ b/storage/innobase/include/trx0trx.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2015, 2022, MariaDB Corporation.
+Copyright (c) 2015, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -774,13 +774,17 @@ public:
 	const char*	op_info;	/*!< English text describing the
 					current operation, or an empty
 					string */
-	uint		isolation_level;/*!< TRX_ISO_REPEATABLE_READ, ... */
-	bool		check_foreigns;	/*!< normally TRUE, but if the user
-					wants to suppress foreign key checks,
-					(in table imports, for example) we
-					set this FALSE */
+  /** TRX_ISO_REPEATABLE_READ, ... */
+  unsigned isolation_level:2;
+  /** normally set; "SET foreign_key_checks=0" can be issued to suppress
+  foreign key checks, in table imports, for example */
+  unsigned check_foreigns:1;
+  /** normally set; "SET unique_checks=0, foreign_key_checks=0"
+  enables bulk insert into an empty table */
+  unsigned check_unique_secondary:1;
+
   /** whether an insert into an empty table is active */
-  bool bulk_insert;
+  unsigned bulk_insert:1;
 	/*------------------------------*/
 	/* MySQL has a transaction coordinator to coordinate two phase
 	commit between multiple storage engines and the binary log. When
@@ -794,13 +798,6 @@ public:
 	/** whether this is holding the prepare mutex */
 	bool		active_commit_ordered;
 	/*------------------------------*/
-	bool		check_unique_secondary;
-					/*!< normally TRUE, but if the user
-					wants to speed up inserts by
-					suppressing unique key checks
-					for secondary indexes when we decide
-					if we can use the insert buffer for
-					them, we set this FALSE */
 	bool		flush_log_later;/* In 2PC, we hold the
 					prepare_commit mutex across
 					both phases. In that case, we
diff --git a/storage/innobase/include/univ.i b/storage/innobase/include/univ.i
index d06343fcabe..93352b279b1 100644
--- a/storage/innobase/include/univ.i
+++ b/storage/innobase/include/univ.i
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1994, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2013, 2022, MariaDB Corporation.
+Copyright (c) 2013, 2023, MariaDB Corporation.
 Copyright (c) 2008, Google Inc.
 
 Portions of this file contain modifications contributed and copyrighted by
@@ -142,7 +142,6 @@ using the call command. */
 						assertions. */
 #define UNIV_LRU_DEBUG				/* debug the buffer pool LRU */
 #define UNIV_HASH_DEBUG				/* debug HASH_ macros */
-#define UNIV_IBUF_DEBUG				/* debug the insert buffer */
 #define UNIV_PERF_DEBUG                         /* debug flag that enables
                                                 light weight performance
                                                 related stuff. */
@@ -475,9 +474,6 @@ extern mysql_pfs_key_t fts_cache_mutex_key;
 extern mysql_pfs_key_t fts_cache_init_mutex_key;
 extern mysql_pfs_key_t fts_delete_mutex_key;
 extern mysql_pfs_key_t fts_doc_id_mutex_key;
-extern mysql_pfs_key_t ibuf_bitmap_mutex_key;
-extern mysql_pfs_key_t ibuf_mutex_key;
-extern mysql_pfs_key_t ibuf_pessimistic_insert_mutex_key;
 extern mysql_pfs_key_t recalc_pool_mutex_key;
 extern mysql_pfs_key_t purge_sys_pq_mutex_key;
 extern mysql_pfs_key_t recv_sys_mutex_key;
diff --git a/storage/innobase/log/log0log.cc b/storage/innobase/log/log0log.cc
index 4e9ed1263f6..e144b9fea38 100644
--- a/storage/innobase/log/log0log.cc
+++ b/storage/innobase/log/log0log.cc
@@ -2,7 +2,7 @@
 
 Copyright (c) 1995, 2017, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2009, Google Inc.
-Copyright (c) 2014, 2022, MariaDB Corporation.
+Copyright (c) 2014, 2023, MariaDB Corporation.
 
 Portions of this file contain modifications contributed and copyrighted by
 Google, Inc. Those modifications are gratefully acknowledged and are described
@@ -913,15 +913,6 @@ void log_write_up_to(lsn_t lsn, bool durable,
 {
   ut_ad(!srv_read_only_mode);
   ut_ad(lsn != LSN_MAX);
-
-  if (UNIV_UNLIKELY(recv_no_ibuf_operations))
-  {
-    /* A non-final batch of recovery is active no writes to the log
-    are allowed yet. */
-    ut_a(!callback);
-    return;
-  }
-
   ut_ad(lsn <= log_sys.get_lsn());
 
 #ifdef HAVE_PMEM
@@ -947,6 +938,7 @@ repeat:
   if (write_lock.acquire(lsn, durable ? nullptr : callback) ==
       group_commit_lock::ACQUIRED)
   {
+    ut_ad(!recv_no_log_write || srv_operation != SRV_OPERATION_NORMAL);
     log_sys.latch.wr_lock(SRW_LOCK_CALL);
     pending_write_lsn= write_lock.release(log_sys.write_buf<true>());
   }
@@ -1079,11 +1071,9 @@ ATTRIBUTE_COLD void logs_empty_and_mark_files_at_shutdown()
 
 	ib::info() << "Starting shutdown...";
 
-	/* Wait until the master thread and all other operations are idle: our
+	/* Wait until the master task and all other operations are idle: our
 	algorithm only works if the server is idle at shutdown */
-	bool do_srv_shutdown = false;
 	if (srv_master_timer) {
-		do_srv_shutdown = srv_fast_shutdown < 2;
 		srv_master_timer.reset();
 	}
 
@@ -1100,11 +1090,6 @@ ATTRIBUTE_COLD void logs_empty_and_mark_files_at_shutdown()
 	}
 	srv_monitor_timer.reset();
 
-	if (do_srv_shutdown) {
-		srv_shutdown(srv_fast_shutdown == 0);
-	}
-
-
 loop:
 	ut_ad(lock_sys.is_initialised() || !srv_was_started);
 	ut_ad(log_sys.is_initialised() || !srv_was_started);
diff --git a/storage/innobase/log/log0recv.cc b/storage/innobase/log/log0recv.cc
index 7d23001962b..1f96fbcc9d6 100644
--- a/storage/innobase/log/log0recv.cc
+++ b/storage/innobase/log/log0recv.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1997, 2017, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2013, 2022, MariaDB Corporation.
+Copyright (c) 2013, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -46,7 +46,6 @@ Created 9/20/1997 Heikki Tuuri
 #include "page0page.h"
 #include "page0cur.h"
 #include "trx0undo.h"
-#include "ibuf0ibuf.h"
 #include "trx0undo.h"
 #include "trx0rec.h"
 #include "fil0fil.h"
@@ -71,17 +70,6 @@ number (FIL_PAGE_LSN) is in the future.  Initially FALSE, and set by
 recv_recovery_from_checkpoint_start(). */
 bool	recv_lsn_checks_on;
 
-/** If the following is TRUE, the buffer pool file pages must be invalidated
-after recovery and no ibuf operations are allowed; this becomes TRUE if
-the log record hash table becomes too full, and log records must be merged
-to file pages already before the recovery is finished: in this case no
-ibuf operations are allowed, as they could modify the pages read in the
-buffer pool before the pages have been recovered to the up-to-date state.
-
-true means that recovery is running and no operations on the log file
-are allowed yet: the variable name is misleading. */
-bool	recv_no_ibuf_operations;
-
 /** The maximum lsn we see for a page during the recovery process. If this
 is bigger than the lsn we are able to scan up to, that is an indication that
 the recovery failed and the database may be corrupt. */
@@ -1089,64 +1077,11 @@ public:
 	void reset()
 	{
 		mysql_mutex_assert_owner(&recv_sys.mutex);
-		ut_ad(recv_no_ibuf_operations);
 		for (map::value_type& i : inits) {
 			i.second.created = false;
 		}
 	}
 
-	/** On the last recovery batch, mark whether there exist
-	buffered changes for the pages that were initialized
-	by buf_page_create() and still reside in the buffer pool.
-	@param[in,out]	mtr	dummy mini-transaction */
-	void mark_ibuf_exist(mtr_t& mtr)
-	{
-		mysql_mutex_assert_owner(&recv_sys.mutex);
-		mtr.start();
-
-		for (const map::value_type& i : inits) {
-			if (!i.second.created) {
-				continue;
-			}
-			if (buf_block_t* block = buf_page_get_low(
-				    i.first, 0, RW_X_LATCH, nullptr,
-				    BUF_GET_IF_IN_POOL,
-				    &mtr, nullptr, false)) {
-				if (UNIV_LIKELY_NULL(block->page.zip.data)) {
-					switch (fil_page_get_type(
-							block->page.zip.data)) {
-					case FIL_PAGE_INDEX:
-					case FIL_PAGE_RTREE:
-						if (page_zip_decompress(
-							    &block->page.zip,
-							    block->page.frame,
-							    true)) {
-							break;
-						}
-						ib::error() << "corrupted "
-							    << block->page.id();
-					}
-				}
-				if (recv_no_ibuf_operations) {
-					mtr.commit();
-					mtr.start();
-					continue;
-				}
-				mysql_mutex_unlock(&recv_sys.mutex);
-				if (ibuf_page_exists(block->page.id(),
-						     block->zip_size())) {
-					block->page.set_ibuf_exist();
-				}
-				mtr.commit();
-				mtr.start();
-				mysql_mutex_lock(&recv_sys.mutex);
-			}
-		}
-
-		mtr.commit();
-		clear();
-	}
-
 	/** Clear the data structure */
 	void clear() { inits.clear(); }
 };
@@ -3436,10 +3371,6 @@ void recv_sys_t::apply(bool last_batch)
     }
   }
 
-  recv_no_ibuf_operations = !last_batch ||
-    srv_operation == SRV_OPERATION_RESTORE ||
-    srv_operation == SRV_OPERATION_RESTORE_EXPORT;
-
   mtr_t mtr;
 
   if (!pages.empty())
@@ -3580,10 +3511,7 @@ next_free_block:
     }
   }
 
-  if (last_batch)
-    /* We skipped this in buf_page_create(). */
-    mlog_init.mark_ibuf_exist(mtr);
-  else
+  if (!last_batch)
   {
     mlog_init.reset();
     log_sys.latch.wr_unlock();
@@ -4298,7 +4226,6 @@ err_exit:
 
 	mysql_mutex_lock(&recv_sys.mutex);
 	recv_sys.apply_log_recs = true;
-	recv_no_ibuf_operations = false;
 	ut_d(recv_no_log_write = srv_operation == SRV_OPERATION_RESTORE
 	     || srv_operation == SRV_OPERATION_RESTORE_EXPORT);
 	if (srv_operation == SRV_OPERATION_NORMAL) {
diff --git a/storage/innobase/mtr/mtr0mtr.cc b/storage/innobase/mtr/mtr0mtr.cc
index 3eacd3ab7e1..04b20de8e96 100644
--- a/storage/innobase/mtr/mtr0mtr.cc
+++ b/storage/innobase/mtr/mtr0mtr.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1995, 2017, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -175,7 +175,6 @@ void mtr_t::start()
 
   m_made_dirty= false;
   m_latch_ex= false;
-  m_inside_ibuf= false;
   m_modifications= false;
   m_log_mode= MTR_LOG_ALL;
   ut_d(m_user_space_id= TRX_SYS_SPACE);
@@ -323,7 +322,6 @@ void mtr_t::release()
 void mtr_t::commit()
 {
   ut_ad(is_active());
-  ut_ad(!is_inside_ibuf());
 
   /* This is a dirty read, for debugging. */
   ut_ad(!m_modifications || !recv_no_log_write);
@@ -506,7 +504,6 @@ void mtr_t::rollback_to_savepoint(ulint begin, ulint end)
 void mtr_t::commit_shrink(fil_space_t &space)
 {
   ut_ad(is_active());
-  ut_ad(!is_inside_ibuf());
   ut_ad(!high_level_read_only);
   ut_ad(m_modifications);
   ut_ad(m_made_dirty);
@@ -613,7 +610,6 @@ void mtr_t::commit_shrink(fil_space_t &space)
 bool mtr_t::commit_file(fil_space_t &space, const char *name)
 {
   ut_ad(is_active());
-  ut_ad(!is_inside_ibuf());
   ut_ad(!high_level_read_only);
   ut_ad(m_modifications);
   ut_ad(!m_made_dirty);
@@ -724,7 +720,6 @@ lsn_t mtr_t::commit_files(lsn_t checkpoint_lsn)
   ut_ad(log_sys.latch.is_write_locked());
 #endif
   ut_ad(is_active());
-  ut_ad(!is_inside_ibuf());
   ut_ad(m_log_mode == MTR_LOG_ALL);
   ut_ad(!m_made_dirty);
   ut_ad(!m_memo);
diff --git a/storage/innobase/page/page0cur.cc b/storage/innobase/page/page0cur.cc
index b019694b9f6..8d3a44d630d 100644
--- a/storage/innobase/page/page0cur.cc
+++ b/storage/innobase/page/page0cur.cc
@@ -2,7 +2,7 @@
 
 Copyright (c) 1994, 2016, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2012, Facebook Inc.
-Copyright (c) 2018, 2022, MariaDB Corporation.
+Copyright (c) 2018, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -1369,8 +1369,7 @@ page_cur_insert_rec_low(
   ut_ad(!!page_is_comp(block->page.frame) == !!rec_offs_comp(offsets));
   ut_ad(fil_page_index_page_check(block->page.frame));
   ut_ad(mach_read_from_8(PAGE_HEADER + PAGE_INDEX_ID + block->page.frame) ==
-        index->id ||
-        mtr->is_inside_ibuf());
+        index->id || index->is_dummy);
   ut_ad(page_dir_get_n_slots(block->page.frame) >= 2);
 
   ut_ad(!page_rec_is_supremum(cur->rec));
@@ -1769,11 +1768,6 @@ static inline void page_zip_dir_add_slot(buf_block_t *block,
 Inserts a record next to page cursor on a compressed and uncompressed
 page.
 
-IMPORTANT: The caller will have to update IBUF_BITMAP_FREE
-if this is a compressed leaf page in a secondary index.
-This has to be done either within the same mini-transaction,
-or by invoking ibuf_reset_free_bits() before mtr_commit().
-
 @return pointer to inserted record
 @return nullptr on failure */
 rec_t*
@@ -1797,8 +1791,7 @@ page_cur_insert_rec_zip(
   ut_ad(rec_offs_comp(offsets));
   ut_ad(fil_page_get_type(page) == FIL_PAGE_INDEX ||
         fil_page_get_type(page) == FIL_PAGE_RTREE);
-  ut_ad(mach_read_from_8(PAGE_HEADER + PAGE_INDEX_ID + page) ==
-        index->id || mtr->is_inside_ibuf());
+  ut_ad(mach_read_from_8(PAGE_HEADER + PAGE_INDEX_ID + page) == index->id);
   ut_ad(!page_get_instant(page));
   ut_ad(!page_cur_is_after_last(cursor));
 #ifdef UNIV_ZIP_DEBUG
@@ -2265,8 +2258,7 @@ page_cur_delete_rec(
 	      == index->table->not_redundant());
 	ut_ad(fil_page_index_page_check(block->page.frame));
 	ut_ad(mach_read_from_8(PAGE_HEADER + PAGE_INDEX_ID + block->page.frame)
-	      == index->id
-	      || mtr->is_inside_ibuf());
+	      == index->id);
 	ut_ad(mtr->is_named_space(index->table->space));
 
 	/* The record must not be the supremum or infimum record. */
diff --git a/storage/innobase/page/page0page.cc b/storage/innobase/page/page0page.cc
index 127eb11f939..63bd39feb4d 100644
--- a/storage/innobase/page/page0page.cc
+++ b/storage/innobase/page/page0page.cc
@@ -2,7 +2,7 @@
 
 Copyright (c) 1994, 2016, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2012, Facebook Inc.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -336,17 +336,13 @@ page_create_zip(
 	/* PAGE_MAX_TRX_ID or PAGE_ROOT_AUTO_INC are always 0 for
 	temporary tables. */
 	ut_ad(max_trx_id == 0 || !index->table->is_temporary());
-	/* In secondary indexes and the change buffer, PAGE_MAX_TRX_ID
+	/* In secondary indexes, PAGE_MAX_TRX_ID
 	must be zero on non-leaf pages. max_trx_id can be 0 when the
-	index consists of an empty root (leaf) page. */
-	ut_ad(max_trx_id == 0
-	      || level == 0
-	      || !dict_index_is_sec_or_ibuf(index)
-	      || index->table->is_temporary());
-	/* In the clustered index, PAGE_ROOT_AUTOINC or
+	index consists of an empty root (leaf) page.
+
+	the clustered index, PAGE_ROOT_AUTOINC or
 	PAGE_MAX_TRX_ID must be 0 on other pages than the root. */
-	ut_ad(level == 0 || max_trx_id == 0
-	      || !dict_index_is_sec_or_ibuf(index)
+	ut_ad(max_trx_id == 0 || level == 0 || index->is_primary()
 	      || index->table->is_temporary());
 
 	buf_block_modify_clock_inc(block);
@@ -390,8 +386,7 @@ page_create_empty(
 	same temp-table in parallel.
 	max_trx_id is ignored for temp tables because it not required
 	for MVCC. */
-	if (dict_index_is_sec_or_ibuf(index)
-	    && !index->table->is_temporary()
+	if (!index->is_primary() && !index->table->is_temporary()
 	    && page_is_leaf(block->page.frame)) {
 		max_trx_id = page_get_max_trx_id(block->page.frame);
 		ut_ad(max_trx_id);
@@ -435,11 +430,6 @@ page_create_empty(
 Differs from page_copy_rec_list_end, because this function does not
 touch the lock table and max trx id on page or compress the page.
 
-IMPORTANT: The caller will have to update IBUF_BITMAP_FREE
-if new_block is a compressed leaf page in a secondary index.
-This has to be done either within the same mini-transaction,
-or by invoking ibuf_reset_free_bits() before mtr_commit().
-
 @return error code */
 dberr_t
 page_copy_rec_list_end_no_locks(
@@ -507,11 +497,6 @@ Copies records from page to new_page, from a given record onward,
 including that record. Infimum and supremum records are not copied.
 The records are copied to the start of the record list on new_page.
 
-IMPORTANT: The caller will have to update IBUF_BITMAP_FREE
-if new_block is a compressed leaf page in a secondary index.
-This has to be done either within the same mini-transaction,
-or by invoking ibuf_reset_free_bits() before mtr_t::commit().
-
 @return pointer to the original successor of the infimum record on new_block
 @retval nullptr on ROW_FORMAT=COMPRESSED page overflow */
 rec_t*
@@ -603,8 +588,7 @@ err_exit:
 	same temp-table in parallel.
 	max_trx_id is ignored for temp tables because it not required
 	for MVCC. */
-	if (dict_index_is_sec_or_ibuf(index)
-	    && page_is_leaf(page)
+	if (!index->is_primary() && page_is_leaf(page)
 	    && !index->table->is_temporary()) {
 		ut_ad(!was_empty || page_dir_get_n_heap(new_page)
 		      == PAGE_HEAP_NO_USER_LOW
@@ -677,11 +661,6 @@ Copies records from page to new_page, up to the given record,
 NOT including that record. Infimum and supremum records are not copied.
 The records are copied to the end of the record list on new_page.
 
-IMPORTANT: The caller will have to update IBUF_BITMAP_FREE
-if new_block is a compressed leaf page in a secondary index.
-This has to be done either within the same mini-transaction,
-or by invoking ibuf_reset_free_bits() before mtr_commit().
-
 @return pointer to the original predecessor of the supremum record on new_block
 @retval nullptr on ROW_FORMAT=COMPRESSED page overflow */
 rec_t*
@@ -786,8 +765,7 @@ corrupted:
 	same temp-table in parallel.
 	max_trx_id is ignored for temp tables because it not required
 	for MVCC. */
-	if (n_core && dict_index_is_sec_or_ibuf(index)
-	    && !index->table->is_temporary()) {
+	if (n_core && !index->is_primary() && !index->table->is_temporary()) {
 		page_update_max_trx_id(new_block,
 				       new_page_zip,
 				       page_get_max_trx_id(block->page.frame),
@@ -2059,7 +2037,7 @@ func_exit2:
 	max_trx_id is ignored for temp tables because it not required
 	for MVCC. */
 	if (!page_is_leaf(page) || page_is_empty(page)
-	    || !dict_index_is_sec_or_ibuf(index)
+	    || index->is_primary()
 	    || index->table->is_temporary()) {
 	} else if (trx_id_t sys_max_trx_id = trx_sys.get_max_trx_id()) {
 		trx_id_t	max_trx_id	= page_get_max_trx_id(page);
diff --git a/storage/innobase/page/page0zip.cc b/storage/innobase/page/page0zip.cc
index 56b58dd87d0..aff01764be6 100644
--- a/storage/innobase/page/page0zip.cc
+++ b/storage/innobase/page/page0zip.cc
@@ -2,7 +2,7 @@
 
 Copyright (c) 2005, 2016, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2012, Facebook Inc.
-Copyright (c) 2014, 2022, MariaDB Corporation.
+Copyright (c) 2014, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -408,8 +408,6 @@ inline void mtr_t::zmemcpy(const buf_block_t &b, void *dest, const void *str,
 static void page_zip_compress_write_log(buf_block_t *block,
                                         dict_index_t *index, mtr_t *mtr)
 {
-  ut_ad(!index->is_ibuf());
-
   if (!mtr->is_logged())
     return;
 
@@ -463,8 +461,7 @@ page_zip_get_n_prev_extern(
 	ut_ad(page_is_leaf(page));
 	ut_ad(page_is_comp(page));
 	ut_ad(dict_table_is_comp(index->table));
-	ut_ad(dict_index_is_clust(index));
-	ut_ad(!dict_index_is_ibuf(index));
+	ut_ad(index->is_primary());
 
 	heap_no = rec_get_heap_no_new(rec);
 	ut_ad(heap_no >= PAGE_HEAP_NO_USER_LOW);
@@ -1282,7 +1279,6 @@ page_zip_compress(
 	ut_ad(page_simple_validate_new((page_t*) page));
 	ut_ad(page_zip_simple_validate(page_zip));
 	ut_ad(dict_table_is_comp(index->table));
-	ut_ad(!dict_index_is_ibuf(index));
 
 	MEM_CHECK_DEFINED(page, srv_page_size);
 
@@ -4374,10 +4370,6 @@ Reorganize and compress a page.  This is a low-level operation for
 compressed pages, to be used when page_zip_compress() fails.
 On success, redo log will be written.
 The function btr_page_reorganize() should be preferred whenever possible.
-IMPORTANT: if page_zip_reorganize() is invoked on a leaf page of a
-non-clustered index, the caller must update the insert buffer free
-bits in the same mini-transaction in such a way that the modification
-will be redo-logged.
 @return error code
 @retval DB_FAIL on overflow; the block_zip will be left intact */
 dberr_t
@@ -4398,7 +4390,6 @@ page_zip_reorganize(
 	ut_ad(mtr->memo_contains_flagged(block, MTR_MEMO_PAGE_X_FIX));
 	ut_ad(block->page.zip.data);
 	ut_ad(page_is_comp(page));
-	ut_ad(!dict_index_is_ibuf(index));
 	ut_ad(!index->table->is_temporary());
 	/* Note that page_zip_validate(page_zip, page, index) may fail here. */
 	MEM_CHECK_DEFINED(page, srv_page_size);
@@ -4505,7 +4496,6 @@ page_zip_copy_recs(
 
 	ut_ad(mtr->memo_contains_flagged(block, MTR_MEMO_PAGE_X_FIX));
 	ut_ad(mtr->memo_contains_page_flagged(src, MTR_MEMO_PAGE_X_FIX));
-	ut_ad(!dict_index_is_ibuf(index));
 	ut_ad(!index->table->is_temporary());
 #ifdef UNIV_ZIP_DEBUG
 	/* The B-tree operations that call this function may set
diff --git a/storage/innobase/rem/rem0cmp.cc b/storage/innobase/rem/rem0cmp.cc
index a77ddafd568..92ec8ba0869 100644
--- a/storage/innobase/rem/rem0cmp.cc
+++ b/storage/innobase/rem/rem0cmp.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1994, 2019, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2020, 2022, MariaDB Corporation.
+Copyright (c) 2020, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -401,8 +401,8 @@ int cmp_dtuple_rec_with_match_low(const dtuple_t *dtuple, const rec_t *rec,
 
 		ut_ad(!dfield_is_ext(dtuple_field));
 
-		ret = cmp_data(type->mtype, type->prtype, !index->is_ibuf()
-			       && index->fields[cur_field].descending,
+		ret = cmp_data(type->mtype, type->prtype,
+			       index->fields[cur_field].descending,
 			       dtuple_b_ptr, dtuple_f_len,
 			       rec_b_ptr, rec_f_len);
 		if (ret) {
@@ -480,7 +480,6 @@ cmp_dtuple_rec_with_match_bytes(
 	ut_ad(rec_offs_validate(rec, index, offsets));
 	ut_ad(!(REC_INFO_MIN_REC_FLAG
 		& dtuple_get_info_bits(dtuple)));
-	ut_ad(!index->is_ibuf());
 
 	if (UNIV_UNLIKELY(REC_INFO_MIN_REC_FLAG
 			  & rec_get_info_bits(rec, rec_offs_comp(offsets)))) {
@@ -829,32 +828,21 @@ cmp_rec_rec(
 				   dict_index_get_n_unique_in_tree(index));
 
 	for (; cur_field < n_fields; cur_field++) {
-		ulint	mtype;
-		ulint	prtype;
-		bool	descending;
-
-		if (UNIV_UNLIKELY(dict_index_is_ibuf(index))) {
-			/* This is for the insert buffer B-tree. */
-			mtype = DATA_BINARY;
+		const dict_field_t* field = dict_index_get_nth_field(
+			index, cur_field);
+		bool descending = field->descending;
+		ulint mtype = field->col->mtype;
+		ulint prtype = field->col->prtype;
+
+		if (UNIV_LIKELY(!index->is_spatial())) {
+		} else if (cur_field == 0) {
+			ut_ad(DATA_GEOMETRY_MTYPE(mtype));
+			prtype |= DATA_GIS_MBR;
+		} else if (!page_rec_is_leaf(rec2)) {
+			/* Compare the child page number. */
+			ut_ad(cur_field == 1);
+			mtype = DATA_SYS_CHILD;
 			prtype = 0;
-			descending = false;
-		} else {
-			const dict_field_t* field = dict_index_get_nth_field(
-				index, cur_field);
-			descending = field->descending;
-			mtype = field->col->mtype;
-			prtype = field->col->prtype;
-
-			if (UNIV_LIKELY(!dict_index_is_spatial(index))) {
-			} else if (cur_field == 0) {
-				ut_ad(DATA_GEOMETRY_MTYPE(mtype));
-				prtype |= DATA_GIS_MBR;
-			} else if (!page_rec_is_leaf(rec2)) {
-				/* Compare the child page number. */
-				ut_ad(cur_field == 1);
-				mtype = DATA_SYS_CHILD;
-				prtype = 0;
-			}
 		}
 
 		/* We should never encounter an externally stored field.
diff --git a/storage/innobase/rem/rem0rec.cc b/storage/innobase/rem/rem0rec.cc
index da6447c390e..a84cba01ef0 100644
--- a/storage/innobase/rem/rem0rec.cc
+++ b/storage/innobase/rem/rem0rec.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1994, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -479,7 +479,7 @@ rec_offs_make_valid(
 	const bool is_alter_metadata = leaf
 		&& rec_is_alter_metadata(rec, *index);
 	ut_ad((leaf && rec_is_metadata(rec, *index))
-	      || index->is_dummy || index->is_ibuf()
+	      || index->is_dummy
 	      || (leaf
 		  ? rec_offs_n_fields(offsets)
 		  <= dict_index_get_n_fields(index)
@@ -891,18 +891,15 @@ rec_get_offsets_func(
 		/* The infimum and supremum records carry 1 field. */
 		ut_ad(is_user_rec || n == 1);
 		ut_ad(!is_user_rec || n_core || index->is_dummy
-		      || dict_index_is_ibuf(index)
 		      || n == n_fields /* dict_stats_analyze_index_level() */
 		      || n - 1
 		      == dict_index_get_n_unique_in_tree_nonleaf(index));
 		ut_ad(!is_user_rec || !n_core || index->is_dummy
-		      || dict_index_is_ibuf(index)
 		      || n == n_fields /* btr_pcur_restore_position() */
 		      || (n + (index->id == DICT_INDEXES_ID) >= n_core));
 
 		if (is_user_rec && n_core && n < index->n_fields) {
 			ut_ad(!index->is_dummy);
-			ut_ad(!dict_index_is_ibuf(index));
 			n = index->n_fields;
 		}
 	}
@@ -1993,7 +1990,7 @@ rec_copy_prefix_to_buf(
 						or NULL */
 	ulint*			buf_size)	/*!< in/out: buffer size */
 {
-	ut_ad(n_fields <= index->n_fields || dict_index_is_ibuf(index));
+	ut_ad(n_fields <= index->n_fields);
 	ut_ad(index->n_core_null_bytes <= UT_BITS_IN_BYTES(index->n_nullable));
 	UNIV_PREFETCH_RW(*buf);
 
diff --git a/storage/innobase/row/row0import.cc b/storage/innobase/row/row0import.cc
index c4ee55e79b3..f86b3c8674a 100644
--- a/storage/innobase/row/row0import.cc
+++ b/storage/innobase/row/row0import.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2012, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2015, 2022, MariaDB Corporation.
+Copyright (c) 2015, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -2071,7 +2071,7 @@ dberr_t PageConverter::operator()(buf_block_t* block) UNIV_NOTHROW
 	we no longer evict the pages on DISCARD TABLESPACE. */
 	buf_page_get_low(block->page.id(), get_zip_size(), RW_NO_LATCH,
 			 nullptr, BUF_PEEK_IF_IN_POOL,
-			 nullptr, nullptr, false);
+			 nullptr, nullptr);
 
 	uint16_t page_type;
 
@@ -4256,8 +4256,6 @@ row_import_for_mysql(
 	ut_ad(trx->state == TRX_STATE_ACTIVE);
 	ut_ad(!table->is_readable());
 
-	ibuf_delete_for_discarded_space(table->space_id);
-
 	/* Assign an undo segment for the transaction, so that the
 	transaction will be recovered after a crash. */
 
@@ -4456,12 +4454,6 @@ row_import_for_mysql(
 
 	ut_free(filepath);
 
-	if (err == DB_SUCCESS) {
-		err = ibuf_check_bitmap_on_import(trx, table->space);
-	}
-
-	DBUG_EXECUTE_IF("ib_import_check_bitmap_failure", err = DB_CORRUPTION;);
-
 	if (err != DB_SUCCESS) {
 		return row_import_cleanup(prebuilt, err);
 	}
diff --git a/storage/innobase/row/row0ins.cc b/storage/innobase/row/row0ins.cc
index 590aded1441..52ccce4d0af 100644
--- a/storage/innobase/row/row0ins.cc
+++ b/storage/innobase/row/row0ins.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2016, 2022, MariaDB Corporation.
+Copyright (c) 2016, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -31,7 +31,6 @@ Created 4/20/1996 Heikki Tuuri
 #include "btr0btr.h"
 #include "btr0cur.h"
 #include "mach0data.h"
-#include "ibuf0ibuf.h"
 #include "que0que.h"
 #include "row0upd.h"
 #include "row0sel.h"
@@ -2683,7 +2682,6 @@ commit_exit:
 	}
 
 	cursor = btr_pcur_get_btr_cur(&pcur);
-	cursor->thr = thr;
 
 #ifdef UNIV_DEBUG
 	{
@@ -2949,7 +2947,6 @@ row_ins_sec_index_entry_low(
 	ut_ad(!dict_index_is_clust(index));
 	ut_ad(mode == BTR_MODIFY_LEAF || mode == BTR_INSERT_TREE);
 
-	cursor.thr = thr;
 	cursor.rtr_info = NULL;
 	cursor.page_cur.index = index;
 	ut_ad(thr_get_trx(thr)->id != 0);
@@ -2971,6 +2968,7 @@ row_ins_sec_index_entry_low(
 
 	if (index->is_spatial()) {
 		rtr_init_rtr_info(&rtr_info, false, &cursor, index, false);
+		rtr_info.thr = thr;
 		rtr_info_update_btr(&cursor, &rtr_info);
 
 		err = btr_cur_search_to_nth_level(0, entry,
@@ -2984,6 +2982,7 @@ row_ins_sec_index_entry_low(
 			rtr_clean_rtr_info(&rtr_info, true);
 			rtr_init_rtr_info(&rtr_info, false, &cursor,
 					  index, false);
+			rtr_info.thr = thr;
 			rtr_info_update_btr(&cursor, &rtr_info);
 			mtr.start();
 			if (index->table->is_temporary()) {
@@ -3001,14 +3000,6 @@ row_ins_sec_index_entry_low(
 			goto func_exit;});
 
 	} else {
-		if (!index->table->is_temporary()) {
-			search_mode = btr_latch_mode(
-				search_mode
-				| (thr_get_trx(thr)->check_unique_secondary
-				   ? BTR_INSERT | BTR_IGNORE_SEC_UNIQUE
-				   : BTR_INSERT));
-		}
-
 		err = btr_cur_search_to_nth_level(0, entry, PAGE_CUR_LE,
 						  search_mode, &cursor, &mtr);
 	}
@@ -3020,12 +3011,6 @@ row_ins_sec_index_entry_low(
 		goto func_exit;
 	}
 
-	if (cursor.flag == BTR_CUR_INSERT_TO_IBUF) {
-		ut_ad(!dict_index_is_spatial(index));
-		/* The insert was buffered during the search: we are done */
-		goto func_exit;
-	}
-
 #ifdef UNIV_DEBUG
 	{
 		page_t*	page = btr_cur_get_page(&cursor);
@@ -3085,13 +3070,9 @@ row_ins_sec_index_entry_low(
 		locked with s-locks the necessary records to
 		prevent any insertion of a duplicate by another
 		transaction. Let us now reposition the cursor and
-		continue the insertion (bypassing the change buffer). */
+		continue the insertion. */
 		err = btr_cur_search_to_nth_level(
-			0, entry, PAGE_CUR_LE,
-			btr_latch_mode(search_mode
-				       & ~(BTR_INSERT
-					   | BTR_IGNORE_SEC_UNIQUE)),
-			&cursor, &mtr);
+			0, entry, PAGE_CUR_LE, search_mode, &cursor, &mtr);
 		if (err != DB_SUCCESS) {
 			goto func_exit;
 		}
@@ -3322,11 +3303,6 @@ row_ins_sec_index_entry(
 	if (err == DB_FAIL) {
 		mem_heap_empty(heap);
 
-		if (index->table->space == fil_system.sys_space
-		    && !(index->type & (DICT_UNIQUE | DICT_SPATIAL))) {
-			ibuf_free_excess_pages();
-		}
-
 		/* Try then pessimistic descent to the B-tree */
 		log_free_check();
 
diff --git a/storage/innobase/row/row0log.cc b/storage/innobase/row/row0log.cc
index 64b4d02fa18..958975804b2 100644
--- a/storage/innobase/row/row0log.cc
+++ b/storage/innobase/row/row0log.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2011, 2018, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -1701,22 +1701,6 @@ err_exit:
 		if (error) {
 			goto err_exit;
 		}
-#ifdef UNIV_DEBUG
-		switch (btr_pcur_get_btr_cur(pcur)->flag) {
-		case BTR_CUR_DELETE_REF:
-		case BTR_CUR_DEL_MARK_IBUF:
-		case BTR_CUR_DELETE_IBUF:
-		case BTR_CUR_INSERT_TO_IBUF:
-			/* We did not request buffering. */
-			break;
-		case BTR_CUR_HASH:
-		case BTR_CUR_HASH_FAIL:
-		case BTR_CUR_BINARY:
-			goto flag_ok;
-		}
-		ut_ad(0);
-flag_ok:
-#endif /* UNIV_DEBUG */
 
 		if (page_rec_is_infimum(btr_pcur_get_rec(pcur))
 		    || btr_pcur_get_low_match(pcur) < index->n_uniq) {
@@ -1724,8 +1708,8 @@ flag_ok:
 			found, because new_table is being modified by
 			this thread only, and all indexes should be
 			updated in sync. */
-			mtr->commit();
-			return(DB_INDEX_CORRUPT);
+			error = DB_INDEX_CORRUPT;
+			goto err_exit;
 		}
 
 		btr_cur_pessimistic_delete(&error, FALSE,
@@ -1785,22 +1769,6 @@ row_log_table_apply_delete(
 	if (err != DB_SUCCESS) {
 		goto all_done;
 	}
-#ifdef UNIV_DEBUG
-	switch (btr_pcur_get_btr_cur(&pcur)->flag) {
-	case BTR_CUR_DELETE_REF:
-	case BTR_CUR_DEL_MARK_IBUF:
-	case BTR_CUR_DELETE_IBUF:
-	case BTR_CUR_INSERT_TO_IBUF:
-		/* We did not request buffering. */
-		break;
-	case BTR_CUR_HASH:
-	case BTR_CUR_HASH_FAIL:
-	case BTR_CUR_BINARY:
-		goto flag_ok;
-	}
-	ut_ad(0);
-flag_ok:
-#endif /* UNIV_DEBUG */
 
 	if (page_rec_is_infimum(btr_pcur_get_rec(&pcur))
 	    || btr_pcur_get_low_match(&pcur) < index->n_uniq) {
@@ -1934,19 +1902,6 @@ func_exit_committed:
 
 		return error;
 	}
-#ifdef UNIV_DEBUG
-	switch (btr_pcur_get_btr_cur(&pcur)->flag) {
-	case BTR_CUR_DELETE_REF:
-	case BTR_CUR_DEL_MARK_IBUF:
-	case BTR_CUR_DELETE_IBUF:
-	case BTR_CUR_INSERT_TO_IBUF:
-		ut_ad(0);/* We did not request buffering. */
-	case BTR_CUR_HASH:
-	case BTR_CUR_HASH_FAIL:
-	case BTR_CUR_BINARY:
-		break;
-	}
-#endif /* UNIV_DEBUG */
 
 	ut_ad(!page_rec_is_infimum(btr_pcur_get_rec(&pcur))
 	      && btr_pcur_get_low_match(&pcur) >= index->n_uniq);
@@ -2096,8 +2051,17 @@ func_exit_committed:
 		ut_free(pcur.old_rec_buf);
 		pcur.old_rec_buf = nullptr;
 
-		if (ROW_FOUND != row_search_index_entry(
-			    entry, BTR_MODIFY_TREE, &pcur, &mtr)) {
+		error = btr_pcur_open(entry, PAGE_CUR_LE, BTR_MODIFY_TREE,
+				      &pcur, 0, &mtr);
+
+		if (error != DB_SUCCESS) {
+			ut_ad(0);
+			break;
+		}
+
+		if (btr_pcur_is_before_first_on_page(&pcur)
+		    || btr_pcur_get_low_match(&pcur)
+		    != dtuple_get_n_fields(entry)) {
 			ut_ad(0);
 			error = DB_CORRUPTION;
 			break;
diff --git a/storage/innobase/row/row0merge.cc b/storage/innobase/row/row0merge.cc
index 723b4b1d387..d3215464306 100644
--- a/storage/innobase/row/row0merge.cc
+++ b/storage/innobase/row/row0merge.cc
@@ -2227,7 +2227,7 @@ end_of_index:
 						  next_page_no),
 					old_table->space->zip_size(),
 					RW_S_LATCH, nullptr, BUF_GET, &mtr,
-					&err, false);
+					&err);
 				if (!block) {
 					goto err_exit;
 				}
@@ -3715,8 +3715,6 @@ row_merge_mtuple_to_dtuple(
 	dtuple_t*	dtuple,
 	const mtuple_t* mtuple)
 {
-	ut_ad(!dict_index_is_ibuf(index));
-
 	memcpy(dtuple->fields, mtuple->fields,
 	       dtuple->n_fields * sizeof *mtuple->fields);
 }
diff --git a/storage/innobase/row/row0mysql.cc b/storage/innobase/row/row0mysql.cc
index 549d2745223..81879431096 100644
--- a/storage/innobase/row/row0mysql.cc
+++ b/storage/innobase/row/row0mysql.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2000, 2018, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2015, 2022, MariaDB Corporation.
+Copyright (c) 2015, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -43,7 +43,6 @@ Created 9/17/2000 Heikki Tuuri
 #include "fsp0file.h"
 #include "fts0fts.h"
 #include "fts0types.h"
-#include "ibuf0ibuf.h"
 #include "lock0lock.h"
 #include "log0log.h"
 #include "pars0pars.h"
@@ -2334,12 +2333,7 @@ row_discard_tablespace(
 	2) Purge and rollback: we assign a new table id for the
 	table. Since purge and rollback look for the table based on
 	the table id, they see the table as 'dropped' and discard
-	their operations.
-
-	3) Insert buffer: we remove all entries for the tablespace in
-	the insert buffer tree. */
-
-	ibuf_delete_for_discarded_space(table->space_id);
+	their operations. */
 
 	table_id_t	new_id;
 
@@ -2442,9 +2436,8 @@ rollback:
   /* Note: The following cannot be rolled back. Rollback would see the
   UPDATE of SYS_INDEXES.TABLE_ID as two operations: DELETE and INSERT.
   It would invoke btr_free_if_exists() when rolling back the INSERT,
-  effectively dropping all indexes of the table. Furthermore, calls like
-  ibuf_delete_for_discarded_space() are already discarding data
-  before the transaction is committed.
+  effectively dropping all indexes of the table. Furthermore, we are
+  already discarding data before the transaction is committed.
 
   It would be better to remove the integrity-breaking
   ALTER TABLE...DISCARD TABLESPACE operation altogether. */
diff --git a/storage/innobase/row/row0purge.cc b/storage/innobase/row/row0purge.cc
index df042f66521..81b02fea8a3 100644
--- a/storage/innobase/row/row0purge.cc
+++ b/storage/innobase/row/row0purge.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1997, 2017, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -273,10 +273,10 @@ not delete marked version of a clustered index record where DB_TRX_ID
 is newer than the purge view.
 
 NOTE: This function should only be called by the purge thread, only
-while holding a latch on the leaf page of the secondary index entry
-(or keeping the buffer pool watch on the page).  It is possible that
-this function first returns true and then false, if a user transaction
-inserts a record that the secondary index entry would refer to.
+while holding a latch on the leaf page of the secondary index entry.
+It is possible that this function first returns true and then false,
+if a user transaction inserts a record that the secondary index entry
+would refer to.
 However, in that case, the user transaction would also re-insert the
 secondary index entry after purge has removed it and released the leaf
 page latch.
@@ -292,6 +292,7 @@ page latch.
 @param[in]	is_tree		true=pessimistic purge,
 				false=optimistic (leaf-page only)
 @return true if the secondary index record can be purged */
+static
 bool
 row_purge_poss_sec(
 	purge_node_t*	node,
@@ -342,18 +343,14 @@ row_purge_remove_sec_if_poss_tree(
 	ibool			success	= TRUE;
 	dberr_t			err;
 	mtr_t			mtr;
-	enum row_search_result	search_result;
 
 	log_free_check();
 	mtr.start();
 	index->set_modified(mtr);
 	pcur.btr_cur.page_cur.index = index;
 
-	search_result = row_search_index_entry(entry, BTR_PURGE_TREE,
-					       &pcur, &mtr);
-
-	switch (search_result) {
-	case ROW_NOT_FOUND:
+	if (!row_search_index_entry(entry, BTR_PURGE_TREE, &pcur,
+				    nullptr, &mtr)) {
 		/* Not found.  This is a legitimate condition.  In a
 		rollback, InnoDB will remove secondary recs that would
 		be purged anyway.  Then the actual purge will not find
@@ -363,18 +360,7 @@ row_purge_remove_sec_if_poss_tree(
 		index, it will remove it.  Then if/when the purge
 		comes to consider the secondary index record a second
 		time, it will not exist any more in the index. */
-
-		/* fputs("PURGE:........sec entry not found\n", stderr); */
-		/* dtuple_print(stderr, entry); */
 		goto func_exit;
-	case ROW_FOUND:
-		break;
-	case ROW_BUFFERED:
-	case ROW_NOT_DELETED_REF:
-		/* These are invalid outcomes, because the mode passed
-		to row_search_index_entry() did not include any of the
-		flags BTR_INSERT, BTR_DELETE, or BTR_DELETE_MARK. */
-		ut_error;
 	}
 
 	/* We should remove the index record if no later version of the row,
@@ -439,8 +425,6 @@ row_purge_remove_sec_if_poss_leaf(
 {
 	mtr_t			mtr;
 	btr_pcur_t		pcur;
-	enum btr_latch_mode	mode;
-	enum row_search_result	search_result;
 	bool			success	= true;
 
 	log_free_check();
@@ -449,31 +433,21 @@ row_purge_remove_sec_if_poss_leaf(
 	mtr.start();
 	index->set_modified(mtr);
 
-	/* Change buffering is disabled for spatial index and
-	virtual index. */
-	mode = (index->type & (DICT_SPATIAL | DICT_VIRTUAL))
-		? BTR_MODIFY_LEAF : BTR_PURGE_LEAF;
+	const auto mode = BTR_MODIFY_LEAF;
 	pcur.btr_cur.page_cur.index = index;
 
-	/* Set the purge node for the call to row_purge_poss_sec(). */
-	pcur.btr_cur.purge_node = node;
+	bool found;
 	if (index->is_spatial()) {
-		pcur.btr_cur.thr = NULL;
 		index->lock.u_lock(SRW_LOCK_CALL);
-		search_result = row_search_index_entry(
-			entry, mode, &pcur, &mtr);
+		found = !rtr_pcur_open(entry, mode, &pcur, nullptr, &mtr);
 		index->lock.u_unlock();
 	} else {
-		/* Set the query thread, so that ibuf_insert_low() will be
-		able to invoke thd_get_trx(). */
-		pcur.btr_cur.thr = static_cast<que_thr_t*>(
-			que_node_get_parent(node));
-		search_result = row_search_index_entry(
-			entry, mode, &pcur, &mtr);
+		found = btr_pcur_open(entry, PAGE_CUR_LE, mode, &pcur, 0, &mtr)
+			== DB_SUCCESS;
 	}
 
-	switch (search_result) {
-	case ROW_FOUND:
+	if (found && !btr_pcur_is_before_first_on_page(&pcur)
+            && btr_pcur_get_low_match(&pcur) == dtuple_get_n_fields(entry)) {
 		/* Before attempting to purge a record, check
 		if it is safe to do so. */
 		if (row_purge_poss_sec(node, index, entry, &pcur, &mtr, false)) {
@@ -501,25 +475,18 @@ row_purge_remove_sec_if_poss_leaf(
 			if (index->is_spatial()) {
 				const buf_block_t* block = btr_cur_get_block(
 					btr_cur);
+                                const page_id_t id{block->page.id()};
 
-				if (block->page.id().page_no()
-				    != index->page
+				if (id.page_no() != index->page
 				    && page_get_n_recs(block->page.frame) < 2
-				    && !lock_test_prdt_page_lock(
-					    btr_cur->rtr_info
-					    && btr_cur->rtr_info->thr
-					    ? thr_get_trx(
-						    btr_cur->rtr_info->thr)
-					    : nullptr,
-					    block->page.id())) {
+				    && !lock_test_prdt_page_lock(nullptr, id)){
 					/* this is the last record on page,
 					and it has a "page" lock on it,
 					which mean search is still depending
 					on it, so do not delete */
 					DBUG_LOG("purge",
 						 "skip purging last"
-						 " record on page "
-						 << block->page.id());
+						 " record on page " << id);
 					goto func_exit;
 				}
 			}
@@ -527,25 +494,13 @@ row_purge_remove_sec_if_poss_leaf(
 			success = btr_cur_optimistic_delete(btr_cur, 0, &mtr)
 				!= DB_FAIL;
 		}
+	}
 
-		/* (The index entry is still needed,
-		or the deletion succeeded) */
-		/* fall through */
-	case ROW_NOT_DELETED_REF:
-		/* The index entry is still needed. */
-	case ROW_BUFFERED:
-		/* The deletion was buffered. */
-	case ROW_NOT_FOUND:
-		/* The index entry does not exist, nothing to do. */
 func_exit:
-		mtr.commit();
+	mtr.commit();
 cleanup:
-		btr_pcur_close(&pcur); // FIXME: do we need these? when is btr_cur->rtr_info set?
-		return(success);
-	}
-
-	ut_error;
-	return(false);
+	btr_pcur_close(&pcur);
+	return success;
 }
 
 /***********************************************************//**
@@ -598,10 +553,7 @@ Purges a delete marking of a record.
 @retval false the purge needs to be suspended because of
 running out of file space */
 static MY_ATTRIBUTE((nonnull, warn_unused_result))
-bool
-row_purge_del_mark(
-/*===============*/
-	purge_node_t*	node)	/*!< in/out: row purge node */
+bool row_purge_del_mark(purge_node_t *node)
 {
   if (node->index)
   {
diff --git a/storage/innobase/row/row0quiesce.cc b/storage/innobase/row/row0quiesce.cc
index a4d634f2d14..059aee6f140 100644
--- a/storage/innobase/row/row0quiesce.cc
+++ b/storage/innobase/row/row0quiesce.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2012, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2021, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -26,7 +26,6 @@ Created 2012-02-08 by Sunny Bains.
 
 #include "row0quiesce.h"
 #include "row0mysql.h"
-#include "ibuf0ibuf.h"
 #include "srv0start.h"
 #include "trx0purge.h"
 
@@ -533,18 +532,6 @@ row_quiesce_table_start(
 		purge_sys.stop();
 	}
 
-	for (ulint count = 0;
-	     ibuf_merge_space(table->space_id);
-	     ++count) {
-		if (trx_is_interrupted(trx)) {
-			goto aborted;
-		}
-		if (!(count % 20)) {
-			ib::info() << "Merging change buffer entries for "
-				<< table->name;
-		}
-	}
-
 	while (buf_flush_list_space(table->space)) {
 		if (trx_is_interrupted(trx)) {
 			goto aborted;
diff --git a/storage/innobase/row/row0row.cc b/storage/innobase/row/row0row.cc
index b998d27d836..616423e8a21 100644
--- a/storage/innobase/row/row0row.cc
+++ b/storage/innobase/row/row0row.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2018, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2018, 2022, MariaDB Corporation.
+Copyright (c) 2018, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -215,28 +215,20 @@ row_build_index_entry_low(
 		entry = dtuple_create(heap, entry_len);
 	}
 
-	if (dict_index_is_ibuf(index)) {
-		dtuple_set_n_fields_cmp(entry, entry_len);
-		/* There may only be externally stored columns
-		in a clustered index B-tree of a user table. */
-		ut_a(!ext);
-	} else {
-		dtuple_set_n_fields_cmp(
-			entry, dict_index_get_n_unique_in_tree(index));
-		if (dict_index_is_spatial(index)) {
-			/* Set the MBR field */
-			if (!row_build_spatial_index_key(
-				    index, ext,
-				    dtuple_get_nth_field(entry, 0),
-				    dtuple_get_nth_field(
-					    row,
-					    dict_index_get_nth_field(index, i)
-					    ->col->ind), flag, heap)) {
-				return NULL;
-			}
-
-			i = 1;
+	dtuple_set_n_fields_cmp(entry, dict_index_get_n_unique_in_tree(index));
+	if (index->is_spatial()) {
+		/* Set the MBR field */
+		if (!row_build_spatial_index_key(
+			    index, ext,
+			    dtuple_get_nth_field(entry, 0),
+			    dtuple_get_nth_field(
+				    row,
+				    dict_index_get_nth_field(index, i)
+				    ->col->ind), flag, heap)) {
+			return NULL;
 		}
+
+		i = 1;
 	}
 
 	for (; i < entry_len; i++) {
@@ -1262,65 +1254,32 @@ row_get_clust_rec(
 
 /***************************************************************//**
 Searches an index record.
-@return whether the record was found or buffered */
-enum row_search_result
+@return whether the record was found */
+bool
 row_search_index_entry(
 /*===================*/
 	const dtuple_t*	entry,	/*!< in: index entry */
 	btr_latch_mode	mode,	/*!< in: BTR_MODIFY_LEAF, ... */
 	btr_pcur_t*	pcur,	/*!< in/out: persistent cursor, which must
 				be closed by the caller */
+	que_thr_t*	thr,	/*!< in/out: query thread */
 	mtr_t*		mtr)	/*!< in: mtr */
 {
-	ulint	n_fields;
-	ulint	low_match;
-	rec_t*	rec;
-
 	ut_ad(dtuple_check_typed(entry));
 
 	if (pcur->index()->is_spatial()) {
-		if (rtr_pcur_open(pcur->index(), entry, mode, pcur, mtr)) {
-			return ROW_NOT_FOUND;
+		if (rtr_pcur_open(entry, mode, pcur, thr, mtr)) {
+			return false;
 		}
 	} else {
 		if (btr_pcur_open(entry, PAGE_CUR_LE, mode, pcur, 0, mtr)
 		    != DB_SUCCESS) {
-			return ROW_NOT_FOUND;
+			return false;
 		}
 	}
 
-	switch (btr_pcur_get_btr_cur(pcur)->flag) {
-	case BTR_CUR_DELETE_REF:
-		ut_ad(!(~mode & BTR_DELETE));
-		ut_ad(!pcur->index()->is_spatial());
-		return(ROW_NOT_DELETED_REF);
-
-	case BTR_CUR_DEL_MARK_IBUF:
-	case BTR_CUR_DELETE_IBUF:
-	case BTR_CUR_INSERT_TO_IBUF:
-		return(ROW_BUFFERED);
-
-	case BTR_CUR_HASH:
-	case BTR_CUR_HASH_FAIL:
-	case BTR_CUR_BINARY:
-		break;
-	}
-
-	low_match = btr_pcur_get_low_match(pcur);
-
-	rec = btr_pcur_get_rec(pcur);
-
-	n_fields = dtuple_get_n_fields(entry);
-
-	if (page_rec_is_infimum(rec)) {
-
-		return(ROW_NOT_FOUND);
-	} else if (low_match != n_fields) {
-
-		return(ROW_NOT_FOUND);
-	}
-
-	return(ROW_FOUND);
+	return !btr_pcur_is_before_first_on_page(pcur)
+		&& btr_pcur_get_low_match(pcur) == dtuple_get_n_fields(entry);
 }
 
 /*******************************************************************//**
diff --git a/storage/innobase/row/row0sel.cc b/storage/innobase/row/row0sel.cc
index 9d7259ba20c..5f5c6fe6c44 100644
--- a/storage/innobase/row/row0sel.cc
+++ b/storage/innobase/row/row0sel.cc
@@ -2,7 +2,7 @@
 
 Copyright (c) 1997, 2017, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2008, Google Inc.
-Copyright (c) 2015, 2022, MariaDB Corporation.
+Copyright (c) 2015, 2023, MariaDB Corporation.
 
 Portions of this file contain modifications contributed and copyrighted by
 Google, Inc. Those modifications are gratefully acknowledged and are described
@@ -4768,14 +4768,13 @@ wait_table_again:
 		}
 
 	} else if (dtuple_get_n_fields(search_tuple) > 0) {
-		pcur->btr_cur.thr = thr;
 		pcur->old_rec = nullptr;
 
 		if (dict_index_is_spatial(index)) {
 			if (!prebuilt->rtr_info) {
 				prebuilt->rtr_info = rtr_create_rtr_info(
-					set_also_gap_locks, true,
-					btr_pcur_get_btr_cur(pcur), index);
+					set_also_gap_locks, true, thr,
+					btr_pcur_get_btr_cur(pcur));
 				prebuilt->rtr_info->search_tuple = search_tuple;
 				prebuilt->rtr_info->search_mode = mode;
 				rtr_info_update_btr(btr_pcur_get_btr_cur(pcur),
diff --git a/storage/innobase/row/row0uins.cc b/storage/innobase/row/row0uins.cc
index 6567019a33d..3e20503d39c 100644
--- a/storage/innobase/row/row0uins.cc
+++ b/storage/innobase/row/row0uins.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1997, 2017, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -40,7 +40,6 @@ Created 2/25/1997 Heikki Tuuri
 #include "row0row.h"
 #include "row0upd.h"
 #include "que0que.h"
-#include "ibuf0ibuf.h"
 #include "log0log.h"
 #include "fil0fil.h"
 #include <mysql/service_thd_mdl.h>
@@ -266,7 +265,7 @@ row_undo_ins_remove_sec_low(
 	const bool		modify_leaf = mode == BTR_MODIFY_LEAF;
 
 	pcur.btr_cur.page_cur.index = index;
-	row_mtr_start(&mtr, index, !modify_leaf);
+	row_mtr_start(&mtr, index);
 
 	if (modify_leaf) {
 		mode = BTR_MODIFY_LEAF_ALREADY_LATCHED;
@@ -282,19 +281,9 @@ row_undo_ins_remove_sec_low(
 					 | BTR_RTREE_DELETE_MARK
 					 | BTR_RTREE_UNDO_INS)
 			: btr_latch_mode(BTR_PURGE_TREE | BTR_RTREE_UNDO_INS);
-		btr_pcur_get_btr_cur(&pcur)->thr = thr;
 	}
 
-	switch (row_search_index_entry(entry, mode, &pcur, &mtr)) {
-	case ROW_BUFFERED:
-	case ROW_NOT_DELETED_REF:
-		/* These are invalid outcomes, because the mode passed
-		to row_search_index_entry() did not include any of the
-		flags BTR_INSERT, BTR_DELETE, or BTR_DELETE_MARK. */
-		ut_error;
-	case ROW_NOT_FOUND:
-		break;
-	case ROW_FOUND:
+	if (row_search_index_entry(entry, mode, &pcur, thr, &mtr)) {
 		if (dict_index_is_spatial(index)
 		    && rec_get_deleted_flag(
 			    btr_pcur_get_rec(&pcur),
diff --git a/storage/innobase/row/row0umod.cc b/storage/innobase/row/row0umod.cc
index 2d04dca4003..2eadb05eccc 100644
--- a/storage/innobase/row/row0umod.cc
+++ b/storage/innobase/row/row0umod.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1997, 2017, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -33,7 +33,6 @@ Created 2/27/1997 Heikki Tuuri
 #include "trx0purge.h"
 #include "btr0btr.h"
 #include "mach0data.h"
-#include "ibuf0ibuf.h"
 #include "row0undo.h"
 #include "row0vers.h"
 #include "trx0trx.h"
@@ -490,10 +489,9 @@ row_undo_mod_del_mark_or_remove_sec_low(
 	dberr_t			err	= DB_SUCCESS;
 	mtr_t			mtr;
 	mtr_t			mtr_vers;
-	row_search_result	search_result;
 	const bool		modify_leaf = mode == BTR_MODIFY_LEAF;
 
-	row_mtr_start(&mtr, index, !modify_leaf);
+	row_mtr_start(&mtr, index);
 
 	pcur.btr_cur.page_cur.index = index;
 	btr_cur = btr_pcur_get_btr_cur(&pcur);
@@ -504,7 +502,6 @@ row_undo_mod_del_mark_or_remove_sec_low(
 					 | BTR_RTREE_DELETE_MARK
 					 | BTR_RTREE_UNDO_INS)
 			: btr_latch_mode(BTR_PURGE_TREE | BTR_RTREE_UNDO_INS);
-		btr_cur->thr = thr;
 	} else if (!index->is_committed()) {
 		/* The index->online_status may change if the index is
 		or was being created online, but not committed yet. It
@@ -523,10 +520,7 @@ row_undo_mod_del_mark_or_remove_sec_low(
 		ut_ad(!dict_index_is_online_ddl(index));
 	}
 
-	search_result = row_search_index_entry(entry, mode, &pcur, &mtr);
-
-	switch (UNIV_EXPECT(search_result, ROW_FOUND)) {
-	case ROW_NOT_FOUND:
+	if (!row_search_index_entry(entry, mode, &pcur, thr, &mtr)) {
 		/* In crash recovery, the secondary index record may
 		be missing if the UPDATE did not have time to insert
 		the secondary index records before the crash.  When we
@@ -537,14 +531,6 @@ row_undo_mod_del_mark_or_remove_sec_low(
 		before it has inserted all updated secondary index
 		records, then the undo will not find those records. */
 		goto func_exit;
-	case ROW_FOUND:
-		break;
-	case ROW_BUFFERED:
-	case ROW_NOT_DELETED_REF:
-		/* These are invalid outcomes, because the mode passed
-		to row_search_index_entry() did not include any of the
-		flags BTR_INSERT, BTR_DELETE, or BTR_DELETE_MARK. */
-		ut_error;
 	}
 
 	/* We should remove the index record if no prior version of the row,
@@ -665,7 +651,6 @@ row_undo_mod_del_unmark_sec_and_undo_update(
 	trx_t*			trx		= thr_get_trx(thr);
 	const ulint		flags
 		= BTR_KEEP_SYS_FLAG | BTR_NO_LOCKING_FLAG;
-	row_search_result	search_result;
 	const auto		orig_mode = mode;
 
 	pcur.btr_cur.page_cur.index = index;
@@ -682,23 +667,12 @@ row_undo_mod_del_unmark_sec_and_undo_update(
 	}
 
 try_again:
-	row_mtr_start(&mtr, index, mode & 8);
-
-	btr_cur->thr = thr;
+	row_mtr_start(&mtr, index);
 
-	search_result = row_search_index_entry(entry, mode, &pcur, &mtr);
+	mem_heap_t* offsets_heap = nullptr;
+	rec_offs* offsets = nullptr;
 
-	switch (search_result) {
-		mem_heap_t*	heap;
-		mem_heap_t*	offsets_heap;
-		rec_offs*	offsets;
-	case ROW_BUFFERED:
-	case ROW_NOT_DELETED_REF:
-		/* These are invalid outcomes, because the mode passed
-		to row_search_index_entry() did not include any of the
-		flags BTR_INSERT, BTR_DELETE, or BTR_DELETE_MARK. */
-		ut_error;
-	case ROW_NOT_FOUND:
+	if (!row_search_index_entry(entry, mode, &pcur, thr, &mtr)) {
 		/* For spatial index, if first search didn't find an
 		undel-marked rec, try to find a del-marked rec. */
 		if (dict_index_is_spatial(index) && btr_cur->rtr_info->fd_del) {
@@ -720,7 +694,7 @@ try_again:
 				<< " at: " << rec_index_print(
 					btr_cur_get_rec(btr_cur), index);
 			err = DB_DUPLICATE_KEY;
-			break;
+			goto func_exit;
 		}
 
 		ib::warn() << "Record in index " << index->name
@@ -734,8 +708,6 @@ try_again:
 		delete-unmark. */
 		big_rec_t*	big_rec;
 		rec_t*		insert_rec;
-		offsets = NULL;
-		offsets_heap = NULL;
 
 		err = btr_cur_optimistic_insert(
 			flags, btr_cur, &offsets, &offsets_heap,
@@ -764,15 +736,13 @@ try_again:
 		if (offsets_heap) {
 			mem_heap_free(offsets_heap);
 		}
-
-		break;
-	case ROW_FOUND:
+	} else {
+		mem_heap_t*	heap;
 		btr_rec_set_deleted<false>(btr_cur_get_block(btr_cur),
 					   btr_cur_get_rec(btr_cur), &mtr);
 		heap = mem_heap_create(
 			sizeof(upd_t)
 			+ dtuple_get_n_fields(entry) * sizeof(upd_field_t));
-		offsets_heap = NULL;
 		offsets = rec_get_offsets(
 			btr_cur_get_rec(btr_cur),
 			index, nullptr, index->n_core_fields, ULINT_UNDEFINED,
@@ -811,6 +781,7 @@ try_again:
 		mem_heap_free(offsets_heap);
 	}
 
+func_exit:
 	btr_pcur_close(&pcur);
 	mtr_commit(&mtr);
 
diff --git a/storage/innobase/row/row0upd.cc b/storage/innobase/row/row0upd.cc
index a3f940adff5..3cdc8d1cfb9 100644
--- a/storage/innobase/row/row0upd.cc
+++ b/storage/innobase/row/row0upd.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2017, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2015, 2022, MariaDB Corporation.
+Copyright (c) 2015, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -1842,7 +1842,6 @@ row_upd_sec_index_entry(
 	trx_t*			trx	= thr_get_trx(thr);
 	btr_latch_mode		mode;
 	ulint			flags;
-	enum row_search_result	search_result;
 
 	ut_ad(trx->id != 0);
 
@@ -1884,41 +1883,29 @@ row_upd_sec_index_entry(
 	default:
 		index->set_modified(mtr);
 		/* fall through */
-	case IBUF_SPACE_ID:
+	case 0:
 		flags = index->table->no_rollback() ? BTR_NO_ROLLBACK : 0;
 		/* We can only buffer delete-mark operations if there
 		are no foreign key constraints referring to the index. */
 		mode = index->is_spatial()
 			? btr_latch_mode(BTR_MODIFY_LEAF
 					 | BTR_RTREE_DELETE_MARK)
-			: referenced
-			? BTR_MODIFY_LEAF : BTR_DELETE_MARK_LEAF;
+			: BTR_MODIFY_LEAF;
 		break;
 	}
 
-	/* Set the query thread, so that ibuf_insert_low() will be
-	able to invoke thd_get_trx(). */
-	btr_pcur_get_btr_cur(&pcur)->thr = thr;
 	pcur.btr_cur.page_cur.index = index;
 
-	search_result = row_search_index_entry(entry, mode, &pcur, &mtr);
+	bool found = row_search_index_entry(entry, mode, &pcur, thr, &mtr);
 
 	btr_cur = btr_pcur_get_btr_cur(&pcur);
 
 	rec = btr_cur_get_rec(btr_cur);
 
-	switch (search_result) {
-	case ROW_NOT_DELETED_REF:	/* should only occur for BTR_DELETE */
-		ut_error;
-		break;
-	case ROW_BUFFERED:
-		/* Entry was delete marked already. */
-		break;
-
-	case ROW_NOT_FOUND:
+	if (!found) {
 		if (dict_index_is_spatial(index) && btr_cur->rtr_info->fd_del) {
 			/* We found the record, but a delete marked */
-			break;
+			goto done;
 		}
 
 		ib::error()
@@ -1932,8 +1919,7 @@ row_upd_sec_index_entry(
 		ut_ad(btr_validate_index(index, 0) == DB_SUCCESS);
 		ut_ad(0);
 #endif /* UNIV_DEBUG */
-		break;
-	case ROW_FOUND:
+	} else {
 		ut_ad(err == DB_SUCCESS);
 
 		/* Delete mark the old index record; it can already be
@@ -1946,7 +1932,7 @@ row_upd_sec_index_entry(
 				btr_cur_get_block(btr_cur),
 				btr_cur_get_rec(btr_cur), index, thr, &mtr);
 			if (err != DB_SUCCESS) {
-				break;
+				goto done;
 			}
 
 			btr_rec_set_deleted<true>(btr_cur_get_block(btr_cur),
@@ -2009,6 +1995,7 @@ row_upd_sec_index_entry(
 		}
 	}
 
+done:
 	btr_pcur_close(&pcur);
 	mtr_commit(&mtr);
 
diff --git a/storage/innobase/srv/srv0mon.cc b/storage/innobase/srv/srv0mon.cc
index f362708093a..f277ec4ec95 100644
--- a/storage/innobase/srv/srv0mon.cc
+++ b/storage/innobase/srv/srv0mon.cc
@@ -2,7 +2,7 @@
 
 Copyright (c) 2010, 2016, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2012, Facebook Inc.
-Copyright (c) 2013, 2022, MariaDB Corporation.
+Copyright (c) 2013, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -27,7 +27,6 @@ Created 12/9/2009 Jimmy Yang
 
 #include "buf0buf.h"
 #include "dict0mem.h"
-#include "ibuf0ibuf.h"
 #include "lock0lock.h"
 #include "mach0data.h"
 #include "os0file.h"
@@ -527,23 +526,10 @@ static monitor_info_t	innodb_counter_info[] =
 	MONITOR_BUF_PAGE_READ("index_non_leaf","Index Non-leaf",
 			      INDEX_NON_LEAF),
 
-	MONITOR_BUF_PAGE_READ("index_ibuf_leaf", "Insert Buffer Index Leaf",
-			      INDEX_IBUF_LEAF),
-
-	MONITOR_BUF_PAGE_READ("index_ibuf_non_leaf",
-			      "Insert Buffer Index Non-Leaf",
-			       INDEX_IBUF_NON_LEAF),
-
 	MONITOR_BUF_PAGE_READ("undo_log", "Undo Log", UNDO_LOG),
 
 	MONITOR_BUF_PAGE_READ("index_inode", "Index Inode", INODE),
 
-	MONITOR_BUF_PAGE_READ("ibuf_free_list", "Insert Buffer Free List",
-			      IBUF_FREELIST),
-
-	MONITOR_BUF_PAGE_READ("ibuf_bitmap", "Insert Buffer Bitmap",
-			      IBUF_BITMAP),
-
 	MONITOR_BUF_PAGE_READ("system_page", "System", SYSTEM),
 
 	MONITOR_BUF_PAGE_READ("trx_system", "Transaction System", TRX_SYSTEM),
@@ -566,23 +552,10 @@ static monitor_info_t	innodb_counter_info[] =
 	MONITOR_BUF_PAGE_WRITTEN("index_non_leaf","Index Non-leaf",
 				 INDEX_NON_LEAF),
 
-	MONITOR_BUF_PAGE_WRITTEN("index_ibuf_leaf", "Insert Buffer Index Leaf",
-				 INDEX_IBUF_LEAF),
-
-	MONITOR_BUF_PAGE_WRITTEN("index_ibuf_non_leaf",
-				 "Insert Buffer Index Non-Leaf",
-				 INDEX_IBUF_NON_LEAF),
-
 	MONITOR_BUF_PAGE_WRITTEN("undo_log", "Undo Log", UNDO_LOG),
 
 	MONITOR_BUF_PAGE_WRITTEN("index_inode", "Index Inode", INODE),
 
-	MONITOR_BUF_PAGE_WRITTEN("ibuf_free_list", "Insert Buffer Free List",
-				 IBUF_FREELIST),
-
-	MONITOR_BUF_PAGE_WRITTEN("ibuf_bitmap", "Insert Buffer Bitmap",
-				 IBUF_BITMAP),
-
 	MONITOR_BUF_PAGE_WRITTEN("system_page", "System", SYSTEM),
 
 	MONITOR_BUF_PAGE_WRITTEN("trx_system", "Transaction System",
@@ -948,57 +921,6 @@ static monitor_info_t	innodb_counter_info[] =
 	 MONITOR_EXISTING | MONITOR_DISPLAY_CURRENT | MONITOR_DEFAULT_ON),
 	 MONITOR_DEFAULT_START, MONITOR_OVLD_N_FILE_OPENED},
 
-	/* ========== Counters for Change Buffer ========== */
-	{"module_ibuf_system", "change_buffer", "InnoDB Change Buffer",
-	 MONITOR_MODULE,
-	 MONITOR_DEFAULT_START, MONITOR_MODULE_IBUF_SYSTEM},
-
-	{"ibuf_merges_insert", "change_buffer",
-	 "Number of inserted records merged by change buffering",
-	 static_cast<monitor_type_t>(
-	 MONITOR_EXISTING | MONITOR_DEFAULT_ON),
-	 MONITOR_DEFAULT_START, MONITOR_OVLD_IBUF_MERGE_INSERT},
-
-	{"ibuf_merges_delete_mark", "change_buffer",
-	 "Number of deleted records merged by change buffering",
-	 static_cast<monitor_type_t>(
-	 MONITOR_EXISTING | MONITOR_DEFAULT_ON),
-	 MONITOR_DEFAULT_START, MONITOR_OVLD_IBUF_MERGE_DELETE},
-
-	{"ibuf_merges_delete", "change_buffer",
-	 "Number of purge records merged by change buffering",
-	 static_cast<monitor_type_t>(
-	 MONITOR_EXISTING | MONITOR_DEFAULT_ON),
-	 MONITOR_DEFAULT_START, MONITOR_OVLD_IBUF_MERGE_PURGE},
-
-	{"ibuf_merges_discard_insert", "change_buffer",
-	 "Number of insert merged operations discarded",
-	 static_cast<monitor_type_t>(
-	 MONITOR_EXISTING | MONITOR_DEFAULT_ON),
-	 MONITOR_DEFAULT_START, MONITOR_OVLD_IBUF_MERGE_DISCARD_INSERT},
-
-	{"ibuf_merges_discard_delete_mark", "change_buffer",
-	 "Number of deleted merged operations discarded",
-	 static_cast<monitor_type_t>(
-	 MONITOR_EXISTING | MONITOR_DEFAULT_ON),
-	 MONITOR_DEFAULT_START, MONITOR_OVLD_IBUF_MERGE_DISCARD_DELETE},
-
-	{"ibuf_merges_discard_delete", "change_buffer",
-	 "Number of purge merged  operations discarded",
-	 static_cast<monitor_type_t>(
-	 MONITOR_EXISTING | MONITOR_DEFAULT_ON),
-	 MONITOR_DEFAULT_START, MONITOR_OVLD_IBUF_MERGE_DISCARD_PURGE},
-
-	{"ibuf_merges", "change_buffer", "Number of change buffer merges",
-	 static_cast<monitor_type_t>(
-	 MONITOR_EXISTING | MONITOR_DEFAULT_ON),
-	 MONITOR_DEFAULT_START, MONITOR_OVLD_IBUF_MERGES},
-
-	{"ibuf_size", "change_buffer", "Change buffer size in pages",
-	 static_cast<monitor_type_t>(
-	 MONITOR_EXISTING | MONITOR_DEFAULT_ON),
-	 MONITOR_DEFAULT_START, MONITOR_OVLD_IBUF_SIZE},
-
 	/* ========== Counters for server operations ========== */
 	{"module_innodb", "innodb",
 	 "Counter for general InnoDB server wide operations and properties",
@@ -1529,38 +1451,6 @@ srv_mon_process_existing_counter(
 		value = fil_system.n_open;
 		break;
 
-	case MONITOR_OVLD_IBUF_MERGE_INSERT:
-		value = ibuf.n_merged_ops[IBUF_OP_INSERT];
-		break;
-
-	case MONITOR_OVLD_IBUF_MERGE_DELETE:
-		value = ibuf.n_merged_ops[IBUF_OP_DELETE_MARK];
-		break;
-
-	case MONITOR_OVLD_IBUF_MERGE_PURGE:
-		value = ibuf.n_merged_ops[IBUF_OP_DELETE];
-		break;
-
-	case MONITOR_OVLD_IBUF_MERGE_DISCARD_INSERT:
-		value = ibuf.n_discarded_ops[IBUF_OP_INSERT];
-		break;
-
-	case MONITOR_OVLD_IBUF_MERGE_DISCARD_DELETE:
-		value = ibuf.n_discarded_ops[IBUF_OP_DELETE_MARK];
-		break;
-
-	case MONITOR_OVLD_IBUF_MERGE_DISCARD_PURGE:
-		value = ibuf.n_discarded_ops[IBUF_OP_DELETE];
-		break;
-
-	case MONITOR_OVLD_IBUF_MERGES:
-		value = ibuf.n_merges;
-		break;
-
-	case MONITOR_OVLD_IBUF_SIZE:
-		value = ibuf.size;
-		break;
-
 	case MONITOR_OVLD_SERVER_ACTIVITY:
 		value = srv_get_activity_count();
 		break;
diff --git a/storage/innobase/srv/srv0srv.cc b/storage/innobase/srv/srv0srv.cc
index 02c7367cc93..7c4e5a0d890 100644
--- a/storage/innobase/srv/srv0srv.cc
+++ b/storage/innobase/srv/srv0srv.cc
@@ -3,7 +3,7 @@
 Copyright (c) 1995, 2017, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2008, 2009 Google Inc.
 Copyright (c) 2009, Percona Inc.
-Copyright (c) 2013, 2022, MariaDB Corporation.
+Copyright (c) 2013, 2023, MariaDB Corporation.
 
 Portions of this file contain modifications contributed and copyrighted by
 Google, Inc. Those modifications are gratefully acknowledged and are described
@@ -48,7 +48,6 @@ Created 10/8/1995 Heikki Tuuri
 #include "buf0lru.h"
 #include "dict0boot.h"
 #include "dict0load.h"
-#include "ibuf0ibuf.h"
 #include "lock0lock.h"
 #include "log0recv.h"
 #include "mem0mem.h"
@@ -126,9 +125,9 @@ my_bool	srv_read_only_mode;
 /** store to its own file each table created by an user; data
 dictionary tables are in the system tablespace 0 */
 my_bool	srv_file_per_table;
-/** Set if InnoDB operates in read-only mode or innodb-force-recovery
-is greater than SRV_FORCE_NO_TRX_UNDO. */
-my_bool	high_level_read_only;
+/** Set if innodb_read_only is set or innodb_force_recovery
+is SRV_FORCE_NO_UNDO_LOG_SCAN or greater. */
+bool high_level_read_only;
 
 /** Sort buffer size in index creation */
 ulong	srv_sort_buf_size;
@@ -279,7 +278,7 @@ my_bool	srv_print_all_deadlocks;
 INFORMATION_SCHEMA.innodb_cmp_per_index */
 my_bool	srv_cmp_per_index_enabled;
 
-/** innodb_fast_shutdown=1 skips purge and change buffer merge.
+/** innodb_fast_shutdown=1 skips the purge of transaction history.
 innodb_fast_shutdown=2 effectively crashes the server (no log checkpoint).
 innodb_fast_shutdown=3 is a clean shutdown that skips the rollback
 of active transaction (to be done on restart). */
@@ -381,8 +380,6 @@ FILE*	srv_misc_tmpfile;
 ulint		srv_main_active_loops;
 /** Iterations of the loop bounded by the 'srv_idle' label. */
 ulint		srv_main_idle_loops;
-/** Iterations of the loop bounded by the 'srv_shutdown' label. */
-static ulint		srv_main_shutdown_loops;
 /** Log writes involving flush. */
 ulint		srv_log_writes_and_flush;
 
@@ -577,10 +574,9 @@ srv_print_master_thread_info(
 	FILE  *file)    /* in: output stream */
 {
 	fprintf(file, "srv_master_thread loops: " ULINTPF " srv_active, "
-		ULINTPF " srv_shutdown, " ULINTPF " srv_idle\n"
+		ULINTPF " srv_idle\n"
 		"srv_master_thread log flush and writes: " ULINTPF "\n",
 		srv_main_active_loops,
-		srv_main_shutdown_loops,
 		srv_main_idle_loops,
 		srv_log_writes_and_flush);
 }
@@ -798,8 +794,6 @@ srv_printf_innodb_monitor(
 	      "--------\n", file);
 	os_aio_print(file);
 
-	ibuf_print(file);
-
 #ifdef BTR_CUR_HASH_ADAPT
 	if (btr_search_enabled) {
 		fputs("-------------------\n"
@@ -1340,31 +1334,6 @@ static void srv_sync_log_buffer_in_background()
 	}
 }
 
-/** Report progress during shutdown.
-@param last   time of last output
-@param n_read number of page reads initiated for change buffer merge */
-static void srv_shutdown_print(time_t &last, ulint n_read)
-{
-  time_t now= time(nullptr);
-  if (now - last >= 15)
-  {
-    last= now;
-
-    const ulint ibuf_size= ibuf.size;
-    sql_print_information("Completing change buffer merge;"
-                          " %zu page reads initiated;"
-                          " %zu change buffer pages remain",
-                          n_read, ibuf_size);
-#if defined HAVE_SYSTEMD && !defined EMBEDDED_LIBRARY
-    service_manager_extend_timeout(INNODB_EXTEND_TIMEOUT_INTERVAL,
-                                   "Completing change buffer merge;"
-                                   " %zu page reads initiated;"
-                                   " %zu change buffer pages remain",
-                                   n_read, ibuf_size);
-#endif
-  }
-}
-
 /** Perform periodic tasks whenever the server is active.
 @param counter_time  microsecond_interval_timer() */
 static void srv_master_do_active_tasks(ulonglong counter_time)
@@ -1402,32 +1371,6 @@ static void srv_master_do_idle_tasks(ulonglong counter_time)
 		MONITOR_SRV_DICT_LRU_MICROSECOND, counter_time);
 }
 
-/**
-Complete the shutdown tasks such as background DROP TABLE,
-and optionally change buffer merge (on innodb_fast_shutdown=0). */
-void srv_shutdown(bool ibuf_merge)
-{
-	ulint		n_read = 0;
-	time_t		now = time(NULL);
-
-	do {
-		ut_ad(!srv_read_only_mode);
-		ut_ad(srv_shutdown_state == SRV_SHUTDOWN_CLEANUP);
-		++srv_main_shutdown_loops;
-
-		if (ibuf_merge) {
-			srv_main_thread_op_info = "doing insert buffer merge";
-			/* Disallow the use of change buffer to
-			avoid a race condition with
-			ibuf_read_merge_pages() */
-			ibuf_max_size_update(0);
-			log_free_check();
-			n_read = ibuf_contract();
-			srv_shutdown_print(now, n_read);
-		}
-	} while (n_read);
-}
-
 /** The periodic master task controlling the server. */
 void srv_master_callback(void*)
 {
diff --git a/storage/innobase/srv/srv0start.cc b/storage/innobase/srv/srv0start.cc
index 83571939d1b..75116a0201a 100644
--- a/storage/innobase/srv/srv0start.cc
+++ b/storage/innobase/srv/srv0start.cc
@@ -3,7 +3,7 @@
 Copyright (c) 1996, 2017, Oracle and/or its affiliates. All rights reserved.
 Copyright (c) 2008, Google Inc.
 Copyright (c) 2009, Percona Inc.
-Copyright (c) 2013, 2022, MariaDB Corporation.
+Copyright (c) 2013, 2023, MariaDB Corporation.
 
 Portions of this file contain modifications contributed and copyrighted by
 Google, Inc. Those modifications are gratefully acknowledged and are described
@@ -69,7 +69,6 @@ Created 2/16/1996 Heikki Tuuri
 #include "btr0btr.h"
 #include "btr0cur.h"
 #include "rem0rec.h"
-#include "ibuf0ibuf.h"
 #include "srv0start.h"
 #include "srv0srv.h"
 #include "btr0defragment.h"
@@ -95,6 +94,7 @@ Created 2/16/1996 Heikki Tuuri
 #include "row0row.h"
 #include "row0mysql.h"
 #include "btr0pcur.h"
+#include "ibuf0ibuf.h"
 #include "zlib.h"
 #include "log.h"
 
@@ -1021,7 +1021,7 @@ srv_init_abort_low(
 /** Prepare to delete the redo log file. Flush the dirty pages from all the
 buffer pools.  Flush the redo log buffer to the redo log file.
 @return lsn upto which data pages have been flushed. */
-static lsn_t srv_prepare_to_delete_redo_log_file()
+ATTRIBUTE_COLD static lsn_t srv_prepare_to_delete_redo_log_file()
 {
   DBUG_ENTER("srv_prepare_to_delete_redo_log_file");
 
@@ -1090,6 +1090,67 @@ same_size:
   DBUG_RETURN(flushed_lsn);
 }
 
+/** Upgrade the redo log to the latest format, or change its size
+or encryption, before starting to write any log records. */
+ATTRIBUTE_COLD static dberr_t srv_log_rebuild()
+{
+  /* Prepare to delete the old redo log file */
+  const lsn_t lsn{srv_prepare_to_delete_redo_log_file()};
+
+  DBUG_EXECUTE_IF("innodb_log_abort_1", return DB_ERROR;);
+  /* Prohibit redo log writes from any other threads until creating a
+  log checkpoint at the end of create_log_file(). */
+  ut_d(recv_no_log_write= true);
+  DBUG_ASSERT(!buf_pool.any_io_pending());
+
+  /* Close the redo log file, so that we can replace it */
+  log_sys.close_file();
+
+  DBUG_EXECUTE_IF("innodb_log_abort_5", return DB_ERROR;);
+
+  dberr_t err= create_log_file(false, lsn);
+
+  if (err == DB_SUCCESS && log_sys.resize_rename())
+    err = DB_ERROR;
+
+  return err;
+}
+
+/** Rebuild the redo log if needed. */
+static dberr_t srv_log_rebuild_if_needed()
+{
+  if (srv_force_recovery == SRV_FORCE_NO_LOG_REDO)
+    /* Completely ignore the redo log. */
+    return DB_SUCCESS;
+  if (srv_read_only_mode)
+    /* Leave the redo log alone. */
+    return DB_SUCCESS;
+
+  if (log_sys.file_size == srv_log_file_size &&
+      log_sys.format ==
+      (srv_encrypt_log ? log_t::FORMAT_ENC_10_8 : log_t::FORMAT_10_8))
+  {
+    /* No need to add or remove encryption, upgrade, or resize. */
+    delete_log_files();
+    return DB_SUCCESS;
+  }
+
+  return srv_log_rebuild();
+}
+
+ATTRIBUTE_COLD static dberr_t ibuf_log_rebuild_if_needed()
+{
+  mysql_mutex_lock(&recv_sys.mutex);
+  recv_sys.apply(true);
+  mysql_mutex_unlock(&recv_sys.mutex);
+
+  if (recv_sys.is_corrupt_log() || recv_sys.is_corrupt_fs())
+    return DB_CORRUPTION;
+
+  recv_sys.debug_free();
+  return srv_log_rebuild_if_needed();
+}
+
 static tpool::task_group rollback_all_recovered_group(1);
 static tpool::task rollback_all_recovered_task(trx_rollback_all_recovered,
 					       nullptr,
@@ -1128,10 +1189,6 @@ dberr_t srv_start(bool create_new_db)
 	ib::info() << "!!!!!!!! UNIV_DEBUG switched on !!!!!!!!!";
 #endif
 
-#ifdef UNIV_IBUF_DEBUG
-	ib::info() << "!!!!!!!! UNIV_IBUF_DEBUG switched on !!!!!!!!!";
-#endif
-
 	ib::info() << "Compressed tables use zlib " ZLIB_VERSION
 #ifdef UNIV_ZIP_DEBUG
 	      " with validation"
@@ -1227,11 +1284,6 @@ dberr_t srv_start(bool create_new_db)
 		return(srv_init_abort(err));
 	}
 
-	if (srv_read_only_mode) {
-		ib::info() << "Disabling background log and ibuf IO write"
-			<< " threads.";
-	}
-
 	if (os_aio_init()) {
 		ib::error() << "Cannot initialize AIO sub-system";
 
@@ -1377,31 +1429,41 @@ dberr_t srv_start(bool create_new_db)
 	if (create_new_db) {
 		ut_ad(!srv_read_only_mode);
 
-		mtr_start(&mtr);
+		mtr.start();
 		ut_ad(fil_system.sys_space->id == 0);
 		compile_time_assert(TRX_SYS_SPACE == 0);
-		compile_time_assert(IBUF_SPACE_ID == 0);
-		ut_a(fsp_header_init(fil_system.sys_space,
-				     uint32_t(sum_of_new_sizes), &mtr)
-		     == DB_SUCCESS);
-
-		ulint ibuf_root = btr_create(
-			DICT_CLUSTERED | DICT_IBUF, fil_system.sys_space,
-			DICT_IBUF_ID_MIN, nullptr, &mtr, &err);
-
-		mtr_commit(&mtr);
-
-		if (ibuf_root == FIL_NULL) {
-			return srv_init_abort(err);
+		err = fsp_header_init(fil_system.sys_space,
+				      uint32_t(sum_of_new_sizes), &mtr);
+		/* Allocate dummy change buffer pages for backward
+		compatibility and to prevent a downgrade. */
+		if (err != DB_SUCCESS) {
+		} else if (buf_block_t *b =
+			   fseg_create(fil_system.sys_space, PAGE_DATA, &mtr,
+				       &err)) {
+			ut_ad(b->page.id()
+			      == page_id_t(0, FSP_IBUF_HEADER_PAGE_NO));
+			b = fseg_alloc_free_page_general(
+				b->page.frame + PAGE_DATA,
+				FSP_IBUF_TREE_ROOT_PAGE_NO, FSP_UP, false,
+				&mtr, &mtr, &err);
+			if (b) {
+				ut_ad(b->page.id() == page_id_t
+				      (0, FSP_IBUF_TREE_ROOT_PAGE_NO));
+				mtr.set_modified(*b);
+				fsp_init_file_page(fil_system.sys_space, b,
+						   &mtr);
+			} else {
+				ut_ad(err != DB_SUCCESS);
+			}
 		}
-
-		ut_ad(ibuf_root == IBUF_TREE_ROOT_PAGE_NO);
-
 		/* To maintain backward compatibility we create only
 		the first rollback segment before the double write buffer.
 		All the remaining rollback segments will be created later,
 		after the double write buffer has been created. */
-		err = trx_sys_create_sys_pages(&mtr);
+		if (err == DB_SUCCESS) {
+			err = trx_sys_create_sys_pages(&mtr);
+		}
+		mtr.commit();
 
 		if (err != DB_SUCCESS) {
 			return(srv_init_abort(err));
@@ -1435,38 +1497,58 @@ dberr_t srv_start(bool create_new_db)
 
 		recv_sys.dblwr.pages.clear();
 
-		if (err != DB_SUCCESS) {
-			return(srv_init_abort(err));
-		}
+		bool must_upgrade_ibuf = false;
 
 		switch (srv_operation) {
 		case SRV_OPERATION_NORMAL:
 		case SRV_OPERATION_RESTORE_EXPORT:
-			/* Initialize the change buffer. */
-			err = dict_boot();
 			if (err != DB_SUCCESS) {
-				return(srv_init_abort(err));
+				break;
+			}
+
+			err = ibuf_upgrade_needed();
+
+			if (UNIV_UNLIKELY(err == DB_FAIL)) {
+				must_upgrade_ibuf = true;
+				err = ibuf_log_rebuild_if_needed();
 			}
+
+			if (err != DB_SUCCESS) {
+				break;
+			}
+
+			err = dict_boot();
 			/* fall through */
 		case SRV_OPERATION_RESTORE:
-			/* This must precede recv_sys.apply(true). */
+			if (err != DB_SUCCESS) {
+				break;
+			}
+
 			srv_undo_tablespaces_active
 				= trx_rseg_get_n_undo_tablespaces();
 
 			if (srv_operation != SRV_OPERATION_RESTORE) {
 				dict_sys.load_sys_tables();
 			}
-			err = trx_lists_init_at_db_start();
-			if (err != DB_SUCCESS) {
-				return srv_init_abort(err);
+
+			if (UNIV_UNLIKELY(must_upgrade_ibuf)) {
+				dict_load_tablespaces();
+				err = ibuf_upgrade();
+				if (err != DB_SUCCESS) {
+					break;
+				}
 			}
+
+			err = trx_lists_init_at_db_start();
 			break;
-		case SRV_OPERATION_RESTORE_DELTA:
-		case SRV_OPERATION_BACKUP:
-		case SRV_OPERATION_BACKUP_NO_DEFER:
+		default:
 			ut_ad("wrong mariabackup mode" == 0);
 		}
 
+		if (err != DB_SUCCESS) {
+			return srv_init_abort(err);
+		}
+
 		if (srv_force_recovery < SRV_FORCE_NO_LOG_REDO) {
 			/* Apply the hashed log records to the
 			respective file pages, for the last batch of
@@ -1586,47 +1668,10 @@ dberr_t srv_start(bool create_new_db)
 		/* Upgrade or resize or rebuild the redo logs before
 		generating any dirty pages, so that the old redo log
 		file will not be written to. */
+		err = srv_log_rebuild_if_needed();
 
-		if (srv_force_recovery == SRV_FORCE_NO_LOG_REDO) {
-			/* Completely ignore the redo log. */
-		} else if (srv_read_only_mode) {
-			/* Leave the redo log alone. */
-		} else if (log_sys.file_size == srv_log_file_size
-			   && log_sys.format
-			   == (srv_encrypt_log
-			       ? log_t::FORMAT_ENC_10_8
-			       : log_t::FORMAT_10_8)) {
-			/* No need to add or remove encryption,
-			upgrade, or resize. */
-			delete_log_files();
-		} else {
-			/* Prepare to delete the old redo log file */
-			const lsn_t lsn{srv_prepare_to_delete_redo_log_file()};
-
-			DBUG_EXECUTE_IF("innodb_log_abort_1",
-					return(srv_init_abort(DB_ERROR)););
-			/* Prohibit redo log writes from any other
-			threads until creating a log checkpoint at the
-			end of create_log_file(). */
-			ut_d(recv_no_log_write = true);
-			DBUG_ASSERT(!buf_pool.any_io_pending());
-
-			/* Close the redo log file, so that we can replace it */
-			log_sys.close_file();
-
-			DBUG_EXECUTE_IF("innodb_log_abort_5",
-					return(srv_init_abort(DB_ERROR)););
-			DBUG_PRINT("ib_log", ("After innodb_log_abort_5"));
-
-			err = create_log_file(false, lsn);
-
-			if (err == DB_SUCCESS && log_sys.resize_rename()) {
-				err = DB_ERROR;
-			}
-
-			if (err != DB_SUCCESS) {
-				return(srv_init_abort(err));
-			}
+		if (err != DB_SUCCESS) {
+			return(srv_init_abort(err));
 		}
 	}
 
@@ -1678,8 +1723,7 @@ dberr_t srv_start(bool create_new_db)
 			/* Bitmap page types will be reset in
 			buf_dblwr_check_block() without redo logging. */
 			block = buf_page_get(
-				page_id_t(IBUF_SPACE_ID,
-					  FSP_IBUF_HEADER_PAGE_NO),
+				page_id_t(0, FSP_IBUF_HEADER_PAGE_NO),
 				0, RW_X_LATCH, &mtr);
 			if (UNIV_UNLIKELY(!block)) {
 			corrupted_old_page:
@@ -1737,21 +1781,7 @@ dberr_t srv_start(bool create_new_db)
 		}
 
 		if (srv_force_recovery < SRV_FORCE_NO_UNDO_LOG_SCAN) {
-			/* The following call is necessary for the insert
-			buffer to work with multiple tablespaces. We must
-			know the mapping between space id's and .ibd file
-			names.
-
-			In a crash recovery, we check that the info in data
-			dictionary is consistent with what we already know
-			about space id's from the calls to fil_ibd_load().
-
-			In a normal startup, we create the space objects for
-			every table in the InnoDB data dictionary that has
-			an .ibd file.
-
-			We also determine the maximum tablespace id used. */
-			dict_check_tablespaces_and_store_max_id();
+			dict_load_tablespaces();
 		}
 
 		if (srv_force_recovery < SRV_FORCE_NO_TRX_UNDO
@@ -1833,13 +1863,6 @@ skip_monitors:
 				      trx_sys.get_max_trx_id());
 	}
 
-	if (srv_force_recovery == 0) {
-		/* In the change buffer we may have even bigger tablespace
-		id's, because we may have dropped those tablespaces, but
-		the buffered records have not been cleaned yet. */
-		ibuf_update_max_tablespace_id();
-	}
-
 	if (!srv_read_only_mode) {
 		if (create_new_db) {
 			srv_buffer_pool_load_at_startup = FALSE;
@@ -1894,10 +1917,6 @@ void innodb_preshutdown()
     return;
   if (!srv_fast_shutdown && srv_operation == SRV_OPERATION_NORMAL)
   {
-    /* Because a slow shutdown must empty the change buffer, we had
-    better prevent any further changes from being buffered. */
-    innodb_change_buffering= 0;
-
     if (trx_sys.is_initialised())
       while (trx_sys.any_active_transactions())
         std::this_thread::sleep_for(std::chrono::milliseconds(1));
@@ -1963,8 +1982,6 @@ void innodb_shutdown()
 	      || srv_force_recovery >= SRV_FORCE_NO_TRX_UNDO);
 	ut_ad(lock_sys.is_initialised() || !srv_was_started);
 	ut_ad(log_sys.is_initialised() || !srv_was_started);
-	ut_ad(ibuf.index || !srv_was_started
-	      || srv_force_recovery >= SRV_FORCE_NO_DDL_UNDO);
 
 	dict_stats_deinit();
 
@@ -1985,7 +2002,6 @@ void innodb_shutdown()
 		btr_search_disable();
 	}
 #endif /* BTR_CUR_HASH_ADAPT */
-	ibuf_close();
 	log_sys.close();
 	purge_sys.close();
 	trx_sys.close();
diff --git a/storage/innobase/trx/trx0rseg.cc b/storage/innobase/trx/trx0rseg.cc
index 0dc82fd21bc..38855443315 100644
--- a/storage/innobase/trx/trx0rseg.cc
+++ b/storage/innobase/trx/trx0rseg.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -449,7 +449,7 @@ static dberr_t trx_rseg_mem_restore(trx_rseg_t *rseg, trx_id_t &max_trx_id,
     return DB_TABLESPACE_NOT_FOUND;
   dberr_t err;
   const buf_block_t *rseg_hdr=
-    buf_page_get_gen(rseg->page_id(), 0, RW_S_LATCH, nullptr, BUF_GET, mtr,
+    buf_page_get_gen(rseg->page_id(), 0, RW_X_LATCH, nullptr, BUF_GET, mtr,
                      &err);
   if (!rseg_hdr)
     return err;
@@ -580,7 +580,7 @@ dberr_t trx_rseg_array_init()
 
 	for (ulint rseg_id = 0; rseg_id < TRX_SYS_N_RSEGS; rseg_id++) {
 		mtr.start();
-		if (const buf_block_t* sys = trx_sysf_get(&mtr, false)) {
+		if (const buf_block_t* sys = trx_sysf_get(&mtr, true)) {
 			if (rseg_id == 0) {
 				/* In case this is an upgrade from
 				before MariaDB 10.3.5, fetch the base
diff --git a/storage/innobase/trx/trx0sys.cc b/storage/innobase/trx/trx0sys.cc
index 374a9d724bc..ab8c0b34e7d 100644
--- a/storage/innobase/trx/trx0sys.cc
+++ b/storage/innobase/trx/trx0sys.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2017, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2022, MariaDB Corporation.
+Copyright (c) 2017, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -105,7 +105,6 @@ trx_sysf_get_n_rseg_slots()
 /** Initialize the transaction system when creating the database. */
 dberr_t trx_sys_create_sys_pages(mtr_t *mtr)
 {
-  mtr->start();
   mtr->x_lock_space(fil_system.sys_space);
   static_assert(TRX_SYS_SPACE == 0, "compatibility");
 
@@ -114,11 +113,7 @@ dberr_t trx_sys_create_sys_pages(mtr_t *mtr)
   buf_block_t *block= fseg_create(fil_system.sys_space,
                                   TRX_SYS + TRX_SYS_FSEG_HEADER, mtr, &err);
   if (UNIV_UNLIKELY(!block))
-  {
-  error:
-    mtr->commit();
     return err;
-  }
   ut_a(block->page.id() == page_id_t(0, TRX_SYS_PAGE_NO));
 
   mtr->write<2>(*block, FIL_PAGE_TYPE + block->page.frame,
@@ -138,9 +133,8 @@ dberr_t trx_sys_create_sys_pages(mtr_t *mtr)
   buf_block_t *r= trx_rseg_header_create(fil_system.sys_space, 0, 0,
                                          mtr, &err);
   if (UNIV_UNLIKELY(!r))
-    goto error;
+    return err;
   ut_a(r->page.id() == page_id_t(0, FSP_FIRST_RSEG_PAGE_NO));
-  mtr->commit();
 
   return trx_lists_init_at_db_start();
 }
diff --git a/storage/innobase/trx/trx0trx.cc b/storage/innobase/trx/trx0trx.cc
index 0ff20b31771..e5e6de97987 100644
--- a/storage/innobase/trx/trx0trx.cc
+++ b/storage/innobase/trx/trx0trx.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2015, 2022, MariaDB Corporation.
+Copyright (c) 2015, 2023, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -410,12 +410,12 @@ void trx_t::free()
 #endif
   read_view.mem_noaccess();
   MEM_NOACCESS(&lock, sizeof lock);
-  MEM_NOACCESS(&op_info, sizeof op_info);
-  MEM_NOACCESS(&isolation_level, sizeof isolation_level);
-  MEM_NOACCESS(&check_foreigns, sizeof check_foreigns);
+  MEM_NOACCESS(&op_info, sizeof op_info +
+               sizeof(unsigned) /* isolation_level,
+                                   check_foreigns, check_unique_secondary,
+                                   bulk_insert */);
   MEM_NOACCESS(&is_registered, sizeof is_registered);
   MEM_NOACCESS(&active_commit_ordered, sizeof active_commit_ordered);
-  MEM_NOACCESS(&check_unique_secondary, sizeof check_unique_secondary);
   MEM_NOACCESS(&flush_log_later, sizeof flush_log_later);
   MEM_NOACCESS(&must_flush_log_later, sizeof must_flush_log_later);
   MEM_NOACCESS(&duplicates, sizeof duplicates);
diff --git a/storage/rocksdb/mysql-test/rocksdb/r/innodb_i_s_tables_disabled.result b/storage/rocksdb/mysql-test/rocksdb/r/innodb_i_s_tables_disabled.result
index de5ed76ad27..9d67a60cee9 100644
--- a/storage/rocksdb/mysql-test/rocksdb/r/innodb_i_s_tables_disabled.result
+++ b/storage/rocksdb/mysql-test/rocksdb/r/innodb_i_s_tables_disabled.result
@@ -98,12 +98,8 @@ buffer_LRU_unzip_search_num_scan	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	N
 buffer_LRU_unzip_search_scanned_per_call	buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	set_member	Page scanned per single LRU unzip search
 buffer_page_read_index_leaf	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Index Leaf Pages read
 buffer_page_read_index_non_leaf	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Index Non-leaf Pages read
-buffer_page_read_index_ibuf_leaf	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Insert Buffer Index Leaf Pages read
-buffer_page_read_index_ibuf_non_leaf	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Insert Buffer Index Non-Leaf Pages read
 buffer_page_read_undo_log	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Undo Log Pages read
 buffer_page_read_index_inode	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Index Inode Pages read
-buffer_page_read_ibuf_free_list	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Insert Buffer Free List Pages read
-buffer_page_read_ibuf_bitmap	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Insert Buffer Bitmap Pages read
 buffer_page_read_system_page	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of System Pages read
 buffer_page_read_trx_system	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Transaction System Pages read
 buffer_page_read_fsp_hdr	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of File Space Header Pages read
@@ -114,12 +110,8 @@ buffer_page_read_zblob2	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NU
 buffer_page_read_other	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of other/unknown (old version of InnoDB) Pages read
 buffer_page_written_index_leaf	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Index Leaf Pages written
 buffer_page_written_index_non_leaf	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Index Non-leaf Pages written
-buffer_page_written_index_ibuf_leaf	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Insert Buffer Index Leaf Pages written
-buffer_page_written_index_ibuf_non_leaf	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Insert Buffer Index Non-Leaf Pages written
 buffer_page_written_undo_log	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Undo Log Pages written
 buffer_page_written_index_inode	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Index Inode Pages written
-buffer_page_written_ibuf_free_list	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Insert Buffer Free List Pages written
-buffer_page_written_ibuf_bitmap	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Insert Buffer Bitmap Pages written
 buffer_page_written_system_page	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of System Pages written
 buffer_page_written_trx_system	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Transaction System Pages written
 buffer_page_written_fsp_hdr	buffer_page_io	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of File Space Header Pages written
@@ -187,14 +179,6 @@ adaptive_hash_rows_removed	adaptive_hash_index	0	NULL	NULL	NULL	0	NULL	NULL	NULL
 adaptive_hash_rows_deleted_no_hash_entry	adaptive_hash_index	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of rows deleted that did not have corresponding Adaptive Hash Index entries
 adaptive_hash_rows_updated	adaptive_hash_index	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of Adaptive Hash Index rows updated
 file_num_open_files	file_system	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	value	Number of files currently open (innodb_num_open_files)
-ibuf_merges_insert	change_buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of inserted records merged by change buffering
-ibuf_merges_delete_mark	change_buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of deleted records merged by change buffering
-ibuf_merges_delete	change_buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of purge records merged by change buffering
-ibuf_merges_discard_insert	change_buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of insert merged operations discarded
-ibuf_merges_discard_delete_mark	change_buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of deleted merged operations discarded
-ibuf_merges_discard_delete	change_buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of purge merged  operations discarded
-ibuf_merges	change_buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Number of change buffer merges
-ibuf_size	change_buffer	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Change buffer size in pages
 innodb_master_thread_sleeps	server	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of times (seconds) master thread sleeps
 innodb_activity_count	server	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	status_counter	Current server activity count
 innodb_master_active_loops	server	0	NULL	NULL	NULL	0	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	counter	Number of times master thread performs its tasks when server is active