Merge 10.3 into 10.4

The MDEV-17062 fix in commit c4195305b2a8431f39a4c75cc1c66ba43685f7a0
was omitted.

261 files changed, 3750 insertions, 964 deletions

diff --git a/mysql-test/include/binlog_inject_error.inc b/mysql-test/include/binlog_inject_error.inc
index 383f66ba843..ce940352723 100644
--- a/mysql-test/include/binlog_inject_error.inc
+++ b/mysql-test/include/binlog_inject_error.inc
@@ -13,10 +13,10 @@
 # let query= 'CREATE TABLE t1 (a INT)';
 # source include/binlog_inject_error.inc;
 #
-
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 --echo $query;
 --replace_regex /(errno: .*)/(errno: #)/
 --error ER_ERROR_ON_WRITE
 --eval $query
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
diff --git a/mysql-test/main/cache_temporal_4265.result b/mysql-test/main/cache_temporal_4265.result
index 7f215de43fb..1cda7004a6f 100644
--- a/mysql-test/main/cache_temporal_4265.result
+++ b/mysql-test/main/cache_temporal_4265.result
@@ -1,13 +1,12 @@
 create table t1 (a date);
 insert t1 values ('2000-01-02'), ('2001-02-03'), ('2002-03-04');
-set debug_dbug='d,str_to_datetime_warn';
+SET STATEMENT debug_dbug='d,str_to_datetime_warn' for
 select * from t1 where a > date_add('2000-01-01', interval 5 day);
 a
 2001-02-03
 2002-03-04
 Warnings:
 Note	1003	2000-01-01
-set debug_dbug='';
 drop table t1;
 create table t1 (id int not null, ut timestamp(6) not null);
 insert into t1 values(1, '2001-01-01 00:00:00.2');
diff --git a/mysql-test/main/cache_temporal_4265.test b/mysql-test/main/cache_temporal_4265.test
index c62f3c3c506..1af683c617b 100644
--- a/mysql-test/main/cache_temporal_4265.test
+++ b/mysql-test/main/cache_temporal_4265.test
@@ -5,9 +5,9 @@
 
 create table t1 (a date);
 insert t1 values ('2000-01-02'), ('2001-02-03'), ('2002-03-04');
-set debug_dbug='d,str_to_datetime_warn';
-select * from t1 where a > date_add('2000-01-01', interval 5 day);
-set debug_dbug='';
+
+SET STATEMENT debug_dbug='d,str_to_datetime_warn' for
+	select * from t1 where a > date_add('2000-01-01', interval 5 day);
 drop table t1;
 
 #
diff --git a/mysql-test/main/create_or_replace2.result b/mysql-test/main/create_or_replace2.result
index 47431212492..6be0d46bdc1 100644
--- a/mysql-test/main/create_or_replace2.result
+++ b/mysql-test/main/create_or_replace2.result
@@ -4,9 +4,9 @@ drop table if exists t1;
 SET @old_debug= @@session.debug;
 CREATE TABLE t1 (i INT, KEY(i)) ENGINE=InnoDB;
 CREATE OR REPLACE TEMPORARY TABLE tmp (a int, b int, key(a)) engine=myisam;
-set debug_dbug='+d,send_kill_after_delete';
+SET debug_dbug='+d,send_kill_after_delete';
 CREATE OR REPLACE TABLE t1 LIKE tmp;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 SHOW TABLES;
 Tables_in_test
 t1
diff --git a/mysql-test/main/create_or_replace2.test b/mysql-test/main/create_or_replace2.test
index 199e5523811..80c8b635d8d 100644
--- a/mysql-test/main/create_or_replace2.test
+++ b/mysql-test/main/create_or_replace2.test
@@ -19,9 +19,9 @@ SET @old_debug= @@session.debug;
 
 CREATE TABLE t1 (i INT, KEY(i)) ENGINE=InnoDB;
 CREATE OR REPLACE TEMPORARY TABLE tmp (a int, b int, key(a)) engine=myisam;
-set debug_dbug='+d,send_kill_after_delete';
+SET debug_dbug='+d,send_kill_after_delete';
 CREATE OR REPLACE TABLE t1 LIKE tmp;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 SHOW TABLES;
 show create table t1;
 --sync_slave_with_master
diff --git a/mysql-test/main/drop_bad_db_type.result b/mysql-test/main/drop_bad_db_type.result
index 1b691957877..ae6fe708e60 100644
--- a/mysql-test/main/drop_bad_db_type.result
+++ b/mysql-test/main/drop_bad_db_type.result
@@ -1,5 +1,5 @@
-SET @save_dbug = @@debug_dbug;
-set debug_dbug='+d,unstable_db_type';
+SET @saved_dbug = @@debug_dbug;
+SET debug_dbug='+d,unstable_db_type';
 install soname 'ha_archive';
 create table t1 (a int) engine=archive;
 insert t1 values (1),(2),(3);
@@ -33,4 +33,4 @@ t1.frm
 drop table t1;
 db.opt
 uninstall soname 'ha_archive';
-set debug_dbug=@save_dbug;
+SET debug_dbug=@saved_dbug;
diff --git a/mysql-test/main/drop_bad_db_type.test b/mysql-test/main/drop_bad_db_type.test
index 6a3ac6ae00f..ebc732104d3 100644
--- a/mysql-test/main/drop_bad_db_type.test
+++ b/mysql-test/main/drop_bad_db_type.test
@@ -7,8 +7,8 @@ if (!$HA_ARCHIVE_SO) {
 
 let $mysqld_datadir= `select @@datadir`;
 
-SET @save_dbug = @@debug_dbug;
-set debug_dbug='+d,unstable_db_type';
+SET @saved_dbug = @@debug_dbug;
+SET debug_dbug='+d,unstable_db_type';
 
 install soname 'ha_archive';
 create table t1 (a int) engine=archive;
@@ -28,4 +28,4 @@ drop table t1;
 --list_files $mysqld_datadir/test
 uninstall soname 'ha_archive';
 
-set debug_dbug=@save_dbug;
+SET debug_dbug=@saved_dbug;
diff --git a/mysql-test/main/engine_error_in_alter-8453.result b/mysql-test/main/engine_error_in_alter-8453.result
index c5a3375f33c..2c823f83038 100644
--- a/mysql-test/main/engine_error_in_alter-8453.result
+++ b/mysql-test/main/engine_error_in_alter-8453.result
@@ -1,6 +1,7 @@
 create table t1 (a int, b int);
-set debug_dbug='+d,external_lock_failure';
+SET @saved_dbug = @@SESSION.debug_dbug;
+SET debug_dbug='+d,external_lock_failure';
 alter table t1 add column c int;
 ERROR HY000: Got error 168 'KABOOM!' from MyISAM
-set debug_dbug='';
+SET debug_dbug= @saved_dbug;
 drop table t1;
diff --git a/mysql-test/main/engine_error_in_alter-8453.test b/mysql-test/main/engine_error_in_alter-8453.test
index c4600ec07fe..78e6de2d645 100644
--- a/mysql-test/main/engine_error_in_alter-8453.test
+++ b/mysql-test/main/engine_error_in_alter-8453.test
@@ -4,8 +4,9 @@
 --source include/have_debug.inc
 
 create table t1 (a int, b int);
-set debug_dbug='+d,external_lock_failure';
+SET @saved_dbug = @@SESSION.debug_dbug;
+SET debug_dbug='+d,external_lock_failure';
 --error ER_GET_ERRMSG
 alter table t1 add column c int;
-set debug_dbug='';
+SET debug_dbug= @saved_dbug;
 drop table t1;
diff --git a/mysql-test/main/error_simulation.result b/mysql-test/main/error_simulation.result
index 7e728d24fc8..457e5c8ec9c 100644
--- a/mysql-test/main/error_simulation.result
+++ b/mysql-test/main/error_simulation.result
@@ -10,6 +10,7 @@ INSERT INTO t1 VALUES
 ('AAAAAAAAAH','AAAAAAAAAH'), ('AAAAAAAAAI','AAAAAAAAAI'),
 ('AAAAAAAAAJ','AAAAAAAAAJ'), ('AAAAAAAAAK','AAAAAAAAAK');
 set tmp_table_size=1024;
+SET @saved_dbug = @@SESSION.debug_dbug;
 set session debug_dbug="+d,raise_error";
 SELECT MAX(a) FROM t1 GROUP BY a,b;
 ERROR 23000: Can't write; duplicate key in table '(temporary)'
@@ -22,7 +23,7 @@ CREATE TABLE t1 (a INT(100) NOT NULL);
 INSERT INTO t1 VALUES (1), (0), (2);
 SET SESSION debug_dbug='+d,alter_table_only_index_change';
 ALTER TABLE t1 ADD INDEX a(a);
-SET SESSION debug_dbug=DEFAULT;
+SET debug_dbug= @saved_dbug;
 SHOW CREATE TABLE t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
@@ -42,7 +43,7 @@ CREATE TABLE t1(a BLOB);
 SET SESSION debug_dbug="+d,bug42064_simulate_oom";
 INSERT INTO t1 VALUES("");
 Got one of the listed errors
-SET SESSION debug_dbug=DEFAULT;
+SET debug_dbug= @saved_dbug;
 DROP TABLE t1;
 #
 # Bug#41660: Sort-index_merge for non-first join table may require 
@@ -79,7 +80,7 @@ a	a	b	filler
 7	1	1	data
 8	1	1	data
 9	1	1	data
-SET SESSION debug_dbug= DEFAULT;
+SET debug_dbug= @saved_dbug;
 SET optimizer_switch=@save_optimizer_switch;
 DROP TABLE t1, t2;
 #
@@ -92,7 +93,7 @@ INSERT INTO t2 VALUES (1),(2);
 SET SESSION debug_dbug="+d,bug11747970_raise_error";
 INSERT IGNORE INTO t2 SELECT f1 FROM t1 a WHERE NOT EXISTS (SELECT 1 FROM t2 b WHERE a.f1 = b.f1);
 ERROR 70100: Query execution was interrupted
-SET SESSION debug_dbug = DEFAULT;
+SET debug_dbug= @saved_dbug;
 DROP TABLE t1,t2;
 #
 # End of 5.1 tests
@@ -126,4 +127,4 @@ SET SESSION debug_dbug="+d,simulate_create_virtual_tmp_table_out_of_memory";
 SELECT f1(1);
 Got one of the listed errors
 DROP FUNCTION f1;
-SET SESSION debug_dbug=DEFAULT;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/main/error_simulation.test b/mysql-test/main/error_simulation.test
index 1debed871c7..f713e2da6ba 100644
--- a/mysql-test/main/error_simulation.test
+++ b/mysql-test/main/error_simulation.test
@@ -21,6 +21,7 @@ set tmp_table_size=1024;
 
 # Set debug flag so an error is returned when
 # tmp table in query is converted from heap to myisam
+SET @saved_dbug = @@SESSION.debug_dbug;
 set session debug_dbug="+d,raise_error";
 
 --error ER_DUP_KEY
@@ -36,7 +37,7 @@ CREATE TABLE t1 (a INT(100) NOT NULL);
 INSERT INTO t1 VALUES (1), (0), (2);
 SET SESSION debug_dbug='+d,alter_table_only_index_change';
 ALTER TABLE t1 ADD INDEX a(a);
-SET SESSION debug_dbug=DEFAULT;
+SET debug_dbug= @saved_dbug;
 SHOW CREATE TABLE t1;
 SELECT * FROM t1;
 DROP TABLE t1;
@@ -51,7 +52,7 @@ SET SESSION debug_dbug="+d,bug42064_simulate_oom";
 # May fail with either ER_OUT_OF_RESOURCES or EE_OUTOFMEMORY
 --error ER_OUT_OF_RESOURCES, 5
 INSERT INTO t1 VALUES("");
-SET SESSION debug_dbug=DEFAULT;
+SET debug_dbug= @saved_dbug;
 
 DROP TABLE t1;
 
@@ -84,7 +85,7 @@ EXPLAIN
 SELECT * FROM t1 LEFT JOIN t2 ON ( t2.a < 10 OR t2.b < 10 );
 SELECT * FROM t1 LEFT JOIN t2 ON ( t2.a < 10 OR t2.b < 10 );
 
-SET SESSION debug_dbug= DEFAULT;
+SET debug_dbug= @saved_dbug;
 
 SET optimizer_switch=@save_optimizer_switch;
 
@@ -101,7 +102,7 @@ INSERT INTO t2 VALUES (1),(2);
 SET SESSION debug_dbug="+d,bug11747970_raise_error";
 --error ER_QUERY_INTERRUPTED
 INSERT IGNORE INTO t2 SELECT f1 FROM t1 a WHERE NOT EXISTS (SELECT 1 FROM t2 b WHERE a.f1 = b.f1);
-SET SESSION debug_dbug = DEFAULT;
+SET debug_dbug= @saved_dbug;
 DROP TABLE t1,t2;
 
 
@@ -156,4 +157,4 @@ SET SESSION debug_dbug="+d,simulate_create_virtual_tmp_table_out_of_memory";
 --error ER_OUT_OF_RESOURCES, 5
 SELECT f1(1);
 DROP FUNCTION f1;
-SET SESSION debug_dbug=DEFAULT;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/main/func_regexp_pcre_debug.result b/mysql-test/main/func_regexp_pcre_debug.result
index e44492fca72..40a379a077d 100644
--- a/mysql-test/main/func_regexp_pcre_debug.result
+++ b/mysql-test/main/func_regexp_pcre_debug.result
@@ -1,10 +1,9 @@
-SET debug_dbug='+d,pcre_exec_error_123';
+SET STATEMENT debug_dbug='+d,pcre_exec_error_123' for
 SELECT 'a' RLIKE 'a';
 'a' RLIKE 'a'
 0
 Warnings:
 Warning	1139	Got error 'pcre_exec: Internal error (-123)' from regexp
-SET debug_dbug='';
 SELECT 'a' RLIKE 'a';
 'a' RLIKE 'a'
 1
diff --git a/mysql-test/main/func_regexp_pcre_debug.test b/mysql-test/main/func_regexp_pcre_debug.test
index c2581fa4110..cbf5c4a17ee 100644
--- a/mysql-test/main/func_regexp_pcre_debug.test
+++ b/mysql-test/main/func_regexp_pcre_debug.test
@@ -1,6 +1,5 @@
 --source include/have_debug.inc
 
-SET debug_dbug='+d,pcre_exec_error_123';
+SET STATEMENT debug_dbug='+d,pcre_exec_error_123' for
 SELECT 'a' RLIKE 'a';
-SET debug_dbug='';
 SELECT 'a' RLIKE 'a';
diff --git a/mysql-test/main/join_cache.result b/mysql-test/main/join_cache.result
index ce0855602cc..cb9cdfa0214 100644
--- a/mysql-test/main/join_cache.result
+++ b/mysql-test/main/join_cache.result
@@ -6067,6 +6067,79 @@ select f2 from t2,t1 where f2 = 0;
 f2
 drop table t1, t2;
 set join_buffer_size=@save_join_buffer_size;
+#
+# MDEV-21243: Join buffer: condition is checked in wrong place for range access
+#
+create table t1(a int primary key);
+insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+create table t2 (a int);
+insert into t2 select A.a + 10*B.a from t1 A, t1 B;
+create table t3 (
+kp1 int,
+kp2 int,
+col1 int,
+col2 int,
+key (kp1, kp2)
+);
+insert into t3
+select
+A.a,
+B.a,
+A.a + 100*B.a,
+A.a + 100*B.a
+from
+t2 A, t2 B;
+analyze table t3;
+Table	Op	Msg_type	Msg_text
+test.t3	analyze	status	Engine-independent statistics collected
+test.t3	analyze	status	Table is already up to date
+# The following must have "B.col1 + 1 < 33333" attached to table B
+# and not to the block-nl-join node:
+explain format=json
+select *
+from t1 a, t3 b
+where
+b.kp1=a.a and
+b.kp1 <= 10 and
+b.kp2 <= 10 and
+b.col1 +1 < 33333;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "table": {
+      "table_name": "a",
+      "access_type": "index",
+      "possible_keys": ["PRIMARY"],
+      "key": "PRIMARY",
+      "key_length": "4",
+      "used_key_parts": ["a"],
+      "rows": 10,
+      "filtered": 100,
+      "attached_condition": "a.a <= 10",
+      "using_index": true
+    },
+    "block-nl-join": {
+      "table": {
+        "table_name": "b",
+        "access_type": "range",
+        "possible_keys": ["kp1"],
+        "key": "kp1",
+        "key_length": "10",
+        "used_key_parts": ["kp1", "kp2"],
+        "rows": 836,
+        "filtered": 76.434,
+        "index_condition": "b.kp2 <= 10",
+        "attached_condition": "b.kp2 <= 10 and b.col1 + 1 < 33333"
+      },
+      "buffer_type": "flat",
+      "buffer_size": "54",
+      "join_type": "BNL",
+      "attached_condition": "b.kp1 = a.a"
+    }
+  }
+}
+drop table t1,t2,t3;
 set @@optimizer_switch=@save_optimizer_switch;
 set global innodb_stats_persistent= @innodb_stats_persistent_save;
 set global innodb_stats_persistent_sample_pages=
diff --git a/mysql-test/main/join_cache.test b/mysql-test/main/join_cache.test
index f831c442a3e..edee05cb6a5 100644
--- a/mysql-test/main/join_cache.test
+++ b/mysql-test/main/join_cache.test
@@ -4068,6 +4068,46 @@ select f2 from t2,t1 where f2 = 0;
 drop table t1, t2;
 set join_buffer_size=@save_join_buffer_size;
 
+
+--echo #
+--echo # MDEV-21243: Join buffer: condition is checked in wrong place for range access
+--echo #
+create table t1(a int primary key);
+insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+create table t2 (a int);
+insert into t2 select A.a + 10*B.a from t1 A, t1 B;
+
+create table t3 (
+  kp1 int,
+  kp2 int,
+  col1 int,
+  col2 int,
+  key (kp1, kp2)
+);
+
+insert into t3
+select
+  A.a,
+  B.a,
+  A.a + 100*B.a,
+  A.a + 100*B.a
+from
+  t2 A, t2 B;
+analyze table t3;
+
+--echo # The following must have "B.col1 + 1 < 33333" attached to table B
+--echo # and not to the block-nl-join node:
+explain format=json
+select *
+from t1 a, t3 b
+where
+  b.kp1=a.a and
+  b.kp1 <= 10 and
+  b.kp2 <= 10 and
+  b.col1 +1 < 33333;
+
+drop table t1,t2,t3;
+
 # The following command must be the last one in the file 
 set @@optimizer_switch=@save_optimizer_switch;
 
diff --git a/mysql-test/main/log_slow_debug.result b/mysql-test/main/log_slow_debug.result
index 71a76342aba..16d67d7fdc7 100644
--- a/mysql-test/main/log_slow_debug.result
+++ b/mysql-test/main/log_slow_debug.result
@@ -6,7 +6,7 @@ SET @@GLOBAL.log_output='TABLE';
 FLUSH SLOW LOGS;
 SET @@GLOBAL.slow_query_log=ON;
 SET @@GLOBAL.log_slow_admin_statements=ON;
-SET @save_dbug = @@debug_dbug;
+SET @saved_dbug = @@debug_dbug;
 SET SESSION debug_dbug="+d,simulate_slow_query";
 CREATE PROCEDURE show_slow_log()
 BEGIN
@@ -218,7 +218,7 @@ sql_text
 #
 # Clean up
 #
-SET SESSION debug_dbug=@save_dbug;
+SET SESSION debug_dbug=@saved_dbug;
 TRUNCATE mysql.slow_log;
 SET @@global.slow_query_log= @org_slow_query_log;
 SET @@global.log_output= @org_log_output;
diff --git a/mysql-test/main/log_slow_debug.test b/mysql-test/main/log_slow_debug.test
index 6b7cdd62f8a..aba4cbc8dcb 100644
--- a/mysql-test/main/log_slow_debug.test
+++ b/mysql-test/main/log_slow_debug.test
@@ -9,7 +9,7 @@ SET @@GLOBAL.log_output='TABLE';
 FLUSH SLOW LOGS;
 SET @@GLOBAL.slow_query_log=ON;
 SET @@GLOBAL.log_slow_admin_statements=ON;
-SET @save_dbug = @@debug_dbug;
+SET @saved_dbug = @@debug_dbug;
 SET SESSION debug_dbug="+d,simulate_slow_query";
 
 DELIMITER $$;
@@ -87,7 +87,7 @@ CALL show_slow_log();
 --echo # Clean up
 --echo #
 
-SET SESSION debug_dbug=@save_dbug;
+SET SESSION debug_dbug=@saved_dbug;
 TRUNCATE mysql.slow_log;
 SET @@global.slow_query_log= @org_slow_query_log;
 SET @@global.log_output= @org_log_output;
diff --git a/mysql-test/main/mdev6830.result b/mysql-test/main/mdev6830.result
index d1cf8c98ac1..0048aa174bc 100644
--- a/mysql-test/main/mdev6830.result
+++ b/mysql-test/main/mdev6830.result
@@ -1,3 +1,4 @@
+SET @saved_dbug = @@SESSION.debug_dbug;
 set @@debug_dbug= 'd,opt';
 CREATE TABLE t1 (pk INT PRIMARY KEY) ENGINE=MyISAM;
 CREATE TABLE t2 (
@@ -46,3 +47,4 @@ SELECT * FROM t1, v3, t4 WHERE v3.f1 = t4.f1 AND t4.f2 = 6 AND t1.pk = v3.f5;
 pk	f1	f2	f3	f4	f5	f6	f7	f8	f9	f10	f11	f12	f13	f14	f15	f1	f2
 drop table t1,t2,t3,t4;
 drop view v2,v3;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/main/mdev6830.test b/mysql-test/main/mdev6830.test
index 3898d5bbef6..ab5f19f7093 100644
--- a/mysql-test/main/mdev6830.test
+++ b/mysql-test/main/mdev6830.test
@@ -2,7 +2,7 @@
 # MDEV-6830 Server crashes in best_access_path after a sequence of SELECTs invollving a temptable view
 #
 --source include/have_debug.inc
-
+SET @saved_dbug = @@SESSION.debug_dbug;
 set @@debug_dbug= 'd,opt';
 
 CREATE TABLE t1 (pk INT PRIMARY KEY) ENGINE=MyISAM;
@@ -60,4 +60,4 @@ SELECT * FROM t1, v3, t4 WHERE v3.f1 = t4.f1 AND t4.f2 = 6 AND t1.pk = v3.f5;
 
 drop table t1,t2,t3,t4;
 drop view v2,v3;
-
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/main/merge-big.result b/mysql-test/main/merge-big.result
index 3b6e116986e..bd188d7a856 100644
--- a/mysql-test/main/merge-big.result
+++ b/mysql-test/main/merge-big.result
@@ -7,7 +7,7 @@ drop table if exists t1,t2,t3,t4,t5,t6;
 CREATE TABLE t1 (c1 INT) ENGINE= MyISAM;
 LOCK TABLE t1 WRITE;
 connect  con1,localhost,root,,;
-SET @orig_debug=@@debug;
+SET @orig_debug=@@global.debug_dbug;
 SET GLOBAL debug_dbug="+d,sleep_open_and_lock_after_open";
 INSERT INTO t1 VALUES (1);
 connection default;
diff --git a/mysql-test/main/merge-big.test b/mysql-test/main/merge-big.test
index 9bd2cab2c8a..5873d2eb233 100644
--- a/mysql-test/main/merge-big.test
+++ b/mysql-test/main/merge-big.test
@@ -42,7 +42,7 @@ LOCK TABLE t1 WRITE;
 #SELECT NOW();
     connect (con1,localhost,root,,);
     let $con1_id= `SELECT CONNECTION_ID()`;
-    SET @orig_debug=@@debug;
+    SET @orig_debug=@@global.debug_dbug;
     SET GLOBAL debug_dbug="+d,sleep_open_and_lock_after_open";
     send INSERT INTO t1 VALUES (1);
 connection default;
diff --git a/mysql-test/main/merge_debug.result b/mysql-test/main/merge_debug.result
index 51905e52d24..29858810ff1 100644
--- a/mysql-test/main/merge_debug.result
+++ b/mysql-test/main/merge_debug.result
@@ -3,7 +3,7 @@ set global storage_engine=myisam;
 set session storage_engine=myisam;
 call mtr.add_suppression("Index for table .*crashed' is corrupt; try to repair it");
 drop table if exists crashed,t2,t3,t4;
-SET @orig_debug=@@debug;
+SET @orig_debug=@@global.debug_dbug;
 CREATE TABLE crashed (c1 INT);
 CREATE TABLE t2 (c1 INT);
 CREATE TABLE t3 (c1 INT);
diff --git a/mysql-test/main/merge_debug.test b/mysql-test/main/merge_debug.test
index 3c617cfc545..50017bc1331 100644
--- a/mysql-test/main/merge_debug.test
+++ b/mysql-test/main/merge_debug.test
@@ -14,7 +14,7 @@ call mtr.add_suppression("Index for table .*crashed' is corrupt; try to repair i
 drop table if exists crashed,t2,t3,t4;
 --enable_warnings
 
-SET @orig_debug=@@debug;
+SET @orig_debug=@@global.debug_dbug;
 
 #
 # Check that MariaDB handles reopen that fails without crashing
diff --git a/mysql-test/main/myisam_debug.result b/mysql-test/main/myisam_debug.result
index 9cba8968116..650a3bcb787 100644
--- a/mysql-test/main/myisam_debug.result
+++ b/mysql-test/main/myisam_debug.result
@@ -36,10 +36,10 @@ create table t1 (a int, index(a));
 lock tables t1 write;
 insert t1 values (1),(2),(1);
 set @old_dbug=@@debug_dbug;
-set debug_dbug='+d,mi_lock_database_failure';
+SET debug_dbug='+d,mi_lock_database_failure';
 unlock tables;
 Warnings:
 Error	126	Index for table './test/t1.MYI' is corrupt; try to repair it
 Error	1030	Got error 22 "Invalid argument" from storage engine MyISAM
-set debug_dbug=@old_dbug;
+SET debug_dbug=@old_dbug;
 drop table t1;
diff --git a/mysql-test/main/myisam_debug.test b/mysql-test/main/myisam_debug.test
index 465ecd70895..2861c344b10 100644
--- a/mysql-test/main/myisam_debug.test
+++ b/mysql-test/main/myisam_debug.test
@@ -66,7 +66,7 @@ create table t1 (a int, index(a));
 lock tables t1 write;
 insert t1 values (1),(2),(1);
 set @old_dbug=@@debug_dbug;
-set debug_dbug='+d,mi_lock_database_failure';
+SET debug_dbug='+d,mi_lock_database_failure';
 unlock tables;
-set debug_dbug=@old_dbug;
+SET debug_dbug=@old_dbug;
 drop table t1;
diff --git a/mysql-test/main/range_innodb.result b/mysql-test/main/range_innodb.result
index 8774a623826..44138bdb85e 100644
--- a/mysql-test/main/range_innodb.result
+++ b/mysql-test/main/range_innodb.result
@@ -71,6 +71,7 @@ key(a),key(b),key(c)
 insert into t1
 select A.a+10*B.a, A.a+10*B.a, A.a+10*B.a+100*C.a
 from t0 A, t0 B, t0 C, t0 D where D.a<5;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set @@global.debug_dbug="+d,ha_index_init_fail";
 explain select * from t1 where a=10 and b=10;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
@@ -78,7 +79,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 select * from t1 where a=10 and b=10;
 ERROR HY000: Table definition has changed, please retry transaction
 DROP TABLE t0,t1;
-set @@global.debug_dbug="-d";
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 set @@optimizer_switch= @optimizer_switch_save;
 #
 # MDEV-19634: Assertion `0' failed in row_sel_convert_mysql_key_to_innobase,
diff --git a/mysql-test/main/range_innodb.test b/mysql-test/main/range_innodb.test
index 2c225df27fe..28fb1df13cb 100644
--- a/mysql-test/main/range_innodb.test
+++ b/mysql-test/main/range_innodb.test
@@ -80,12 +80,13 @@ create table t1 (
 insert into t1
 select A.a+10*B.a, A.a+10*B.a, A.a+10*B.a+100*C.a
 from t0 A, t0 B, t0 C, t0 D where D.a<5;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set @@global.debug_dbug="+d,ha_index_init_fail";
 explain select * from t1 where a=10 and b=10;
 --error ER_TABLE_DEF_CHANGED
 select * from t1 where a=10 and b=10;
 DROP TABLE t0,t1;
-set @@global.debug_dbug="-d";
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 set @@optimizer_switch= @optimizer_switch_save;
 
 --echo #
diff --git a/mysql-test/main/range_interrupted-13751.result b/mysql-test/main/range_interrupted-13751.result
index f4f995721ad..68610cdda8e 100644
--- a/mysql-test/main/range_interrupted-13751.result
+++ b/mysql-test/main/range_interrupted-13751.result
@@ -7,10 +7,10 @@ INSERT INTO t1 (c) SELECT c FROM t1;
 INSERT INTO t1 (c) SELECT c FROM t1;
 INSERT INTO t1 (c) SELECT c FROM t1;
 set @old_dbug=@@session.debug_dbug;
-set debug_dbug="+d,kill_join_init_read_record";
+SET debug_dbug="+d,kill_join_init_read_record";
 SELECT 1 FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
 WHERE alias1.c = alias2.c OR alias1.i <= 1
 ;
 ERROR 70100: Query execution was interrupted
-set debug_dbug=@old_dbug;
+SET debug_dbug=@old_dbug;
 DROP TABLE t1;
diff --git a/mysql-test/main/range_interrupted-13751.test b/mysql-test/main/range_interrupted-13751.test
index 8b2c1834ee5..b0793edeb9d 100644
--- a/mysql-test/main/range_interrupted-13751.test
+++ b/mysql-test/main/range_interrupted-13751.test
@@ -14,14 +14,14 @@ INSERT INTO t1 (c) SELECT c FROM t1;
 INSERT INTO t1 (c) SELECT c FROM t1;
 
 set @old_dbug=@@session.debug_dbug;
-set debug_dbug="+d,kill_join_init_read_record";
+SET debug_dbug="+d,kill_join_init_read_record";
 
 --error ER_QUERY_INTERRUPTED
 SELECT 1 FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
 WHERE alias1.c = alias2.c OR alias1.i <= 1
 ;
 
-set debug_dbug=@old_dbug;
+SET debug_dbug=@old_dbug;
 
 DROP TABLE t1;
 
diff --git a/mysql-test/main/select_debug.result b/mysql-test/main/select_debug.result
index 55882ad337a..dfe49aed215 100644
--- a/mysql-test/main/select_debug.result
+++ b/mysql-test/main/select_debug.result
@@ -6,6 +6,7 @@ insert into t1 values (2,2), (1,1);
 create table t2 (a int);
 insert into t2 values (2), (3);
 set session join_cache_level=3;
+SET @saved_dbug = @@SESSION.debug_dbug;
 set @@debug_dbug= 'd,opt';
 explain select t1.b from t1,t2 where t1.b=t2.a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
@@ -16,3 +17,4 @@ b
 2
 set session join_cache_level=default;
 drop table t1,t2;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/main/select_debug.test b/mysql-test/main/select_debug.test
index 49415400db3..922cec7ed7a 100644
--- a/mysql-test/main/select_debug.test
+++ b/mysql-test/main/select_debug.test
@@ -10,6 +10,7 @@ create table t2 (a int);
 insert into t2 values (2), (3);
 
 set session join_cache_level=3;
+SET @saved_dbug = @@SESSION.debug_dbug;
 set @@debug_dbug= 'd,opt';
 
 explain select t1.b from t1,t2 where t1.b=t2.a;
@@ -17,3 +18,4 @@ select t1.b from t1,t2 where t1.b=t2.a;
 
 set session join_cache_level=default;
 drop table t1,t2;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/main/show_explain.result b/mysql-test/main/show_explain.result
index 32364d0ec89..1f44f7bc5ed 100644
--- a/mysql-test/main/show_explain.result
+++ b/mysql-test/main/show_explain.result
@@ -23,7 +23,7 @@ show explain for $thr1;
 ERROR HY000: Target is not running an EXPLAINable command
 connection con1;
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 select count(*) from t1 where a < 100000;
 connection default;
 show explain for $thr2;
@@ -58,10 +58,10 @@ connection con1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	range	a	a	5	NULL	10	Using index condition; Rowid-ordered scan
 set optimizer_switch= @show_expl_tmp;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 # UNION, first branch 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 explain select a from t0 A union select a+1 from t0 B;
 connection default;
 show explain for $thr2;
@@ -76,10 +76,10 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	10	
 2	UNION	B	ALL	NULL	NULL	NULL	NULL	10	
 NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL	
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 # UNION, second branch
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 explain select a from t0 A union select a+1 from t0 B;
 connection default;
 show explain for $thr2;
@@ -94,10 +94,10 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	10	
 2	UNION	B	ALL	NULL	NULL	NULL	NULL	10	
 NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL	
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 # Uncorrelated  subquery, select
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 select a, (select max(a) from t0 B) from t0 A where a<1;
 connection default;
 show explain for $thr2;
@@ -109,10 +109,10 @@ Note	1003	select a, (select max(a) from t0 B) from t0 A where a<1
 connection con1;
 a	(select max(a) from t0 B)
 0	9
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 # Uncorrelated  subquery, explain
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 explain select a, (select max(a) from t0 B) from t0 A where a<1;
 connection default;
 show explain for $thr2;
@@ -125,10 +125,10 @@ connection con1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	10	Using where
 2	SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	10	
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 # correlated  subquery, select
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
 connection default;
 show explain for $thr2;
@@ -140,10 +140,10 @@ Note	1003	select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a
 connection con1;
 a	(select max(a) from t0 b where b.a+a.a<10)
 0	9
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 # correlated  subquery, explain
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
 connection default;
 show explain for $thr2;
@@ -155,10 +155,10 @@ Note	1003	select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a
 connection con1;
 a	(select max(a) from t0 b where b.a+a.a<10)
 0	9
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 # correlated  subquery, select, while inside the subquery
 set @show_explain_probe_select_id=2;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
 connection default;
 show explain for $thr2;
@@ -170,10 +170,10 @@ Note	1003	select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a
 connection con1;
 a	(select max(a) from t0 b where b.a+a.a<10)
 0	9
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 # correlated  subquery, explain, while inside the subquery
 set @show_explain_probe_select_id=2;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
 connection default;
 show explain for $thr2;
@@ -185,10 +185,10 @@ Note	1003	select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a
 connection con1;
 a	(select max(a) from t0 b where b.a+a.a<10)
 0	9
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 # correlated  subquery, explain, while inside the subquery
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_end';
+SET debug_dbug='+d,show_explain_probe_join_exec_end';
 select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
 connection default;
 show explain for $thr2;
@@ -200,12 +200,12 @@ Note	1003	select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a
 connection con1;
 a	(select max(a) from t0 b where b.a+a.a<10)
 0	9
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 # Try to do SHOW EXPLAIN for a query that runs a  SET command:
 #   I've found experimentally that select_id==2 here...
 # 
 set @show_explain_probe_select_id=2;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 set @foo= (select max(a) from t0 where sin(a) >0);
 connection default;
 show explain for $thr2;
@@ -213,13 +213,13 @@ ERROR HY000: Target is not running an EXPLAINable command
 kill query $thr2;
 connection con1;
 ERROR 70100: Query execution was interrupted
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 #
 # Attempt SHOW EXPLAIN for an UPDATE
 #
 create table t2 as select a as a, a as dummy from t0 limit 2;
 set @show_explain_probe_select_id=2;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 update t2 set dummy=0 where (select max(a) from t0 where t2.a + t0.a <3) >3 ;
 connection default;
 show explain for $thr2;
@@ -236,13 +236,13 @@ Warnings:
 Note	1003	update t2 set dummy=0 where (select max(a) from t0 where t2.a + t0.a <3) >3
 connection con1;
 drop table t2;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 #
 # Attempt SHOW EXPLAIN for a DELETE (UPD: now works)
 # 
 create table t2 as select a as a, a as dummy from t0 limit 2;
 set @show_explain_probe_select_id=2;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 delete from t2 where (select max(a) from t0 where t2.a + t0.a <3) >3 ;
 connection default;
 show explain for $thr2;
@@ -259,13 +259,13 @@ Warnings:
 Note	1003	delete from t2 where (select max(a) from t0 where t2.a + t0.a <3) >3
 connection con1;
 drop table t2;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 #
 # Multiple SHOW EXPLAIN calls for one select 
 # 
 create table t2 as select a as a, a as dummy from t0 limit 3;
 set @show_explain_probe_select_id=2;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 select t2.a, ((select max(a) from t0 where t2.a + t0.a <3) >3) as SUBQ from t2;
 connection default;
 show explain for $thr2;
@@ -292,14 +292,14 @@ a	SUBQ
 1	0
 2	0
 drop table t2;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 #
 # SHOW EXPLAIN for SELECT ... ORDER BY with "Using filesort"
 #
 explain select * from t0 order by a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	10	Using filesort
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 set @show_explain_probe_select_id=1;
 select * from t0 order by a;
 connection default;
@@ -320,7 +320,7 @@ a
 7
 8
 9
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 #
 # SHOW EXPLAIN for SELECT ... with "Using temporary"
 #
@@ -329,7 +329,7 @@ explain select distinct a from t0;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	10	Using temporary
 connection con1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 set @show_explain_probe_select_id=1;
 select distinct a from t0;
 connection default;
@@ -350,7 +350,7 @@ a
 7
 8
 9
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 #
 # SHOW EXPLAIN for SELECT ... with "Using temporary; Using filesort"
 #
@@ -359,7 +359,7 @@ explain select distinct a from t0;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	10	Using temporary
 connection con1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 set @show_explain_probe_select_id=1;
 select distinct a from t0;
 connection default;
@@ -380,7 +380,7 @@ a
 7
 8
 9
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 #
 # MDEV-238: SHOW EXPLAIN: Server crashes in JOIN::print_explain with FROM subquery and GROUP BY
 #
@@ -390,7 +390,7 @@ explain SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	5	Using temporary; Using filesort
 1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	5	Using join buffer (flat, BNL join)
-set debug_dbug='+d,show_explain_in_find_all_keys';
+SET debug_dbug='+d,show_explain_in_find_all_keys';
 SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a;
 connection default;
 # FIXED by "conservative assumptions about when QEP is available" fix:
@@ -406,7 +406,7 @@ a
 1
 2
 4
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 DROP TABLE t2;
 #
 # MDEV-239: Assertion `field_types == 0 ... ' failed in Protocol_text::store(double, uint32, String*) with 
@@ -421,7 +421,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 Warnings:
 Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` join `test`.`t2` group by `test`.`t2`.`a`
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_end';
+SET debug_dbug='+d,show_explain_probe_join_exec_end';
 EXPLAIN EXTENDED SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a ;
 connection default;
 show explain for $thr2;
@@ -436,7 +436,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using join buffer (flat, BNL join)
 Warnings:
 Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` join `test`.`t2` group by `test`.`t2`.`a`
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 DROP TABLE t2;
 #
 # MDEV-240: SHOW EXPLAIN: Assertion `this->optimized == 2' failed in 
@@ -453,7 +453,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	6	
 2	DERIVED	t3	system	NULL	NULL	NULL	NULL	1	
 set @show_explain_probe_select_id=2;
-set debug_dbug='+d,show_explain_probe_join_exec_end';
+SET debug_dbug='+d,show_explain_probe_join_exec_end';
 SELECT * FROM v1, t2;
 connection default;
 show explain for $thr2;
@@ -461,14 +461,14 @@ ERROR HY000: Target is not running an EXPLAINable command
 kill query $thr2;
 connection con1;
 ERROR 70100: Query execution was interrupted
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 DROP VIEW v1;
 DROP TABLE t2, t3;
 #
 # MDEV-267: SHOW EXPLAIN: Server crashes in JOIN::print_explain on most of queries
 #
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_end';
+SET debug_dbug='+d,show_explain_probe_join_exec_end';
 select sleep(1);
 connection default;
 show explain for $thr2;
@@ -479,12 +479,12 @@ Note	1003	select sleep(1)
 connection con1;
 sleep(1)
 0
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 #
 # Same as above, but try another reason for JOIN to be degenerate
 #
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_end';
+SET debug_dbug='+d,show_explain_probe_join_exec_end';
 select * from t0 where 1>10;
 connection default;
 show explain for $thr2;
@@ -494,14 +494,14 @@ Warnings:
 Note	1003	select * from t0 where 1>10
 connection con1;
 a
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 #
 # Same as above, but try another reason for JOIN to be degenerate (2)
 #
 create table t3(a int primary key);
 insert into t3 select a from t0;
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_end';
+SET debug_dbug='+d,show_explain_probe_join_exec_end';
 select * from t0,t3 where t3.a=112233;
 connection default;
 show explain for $thr2;
@@ -511,7 +511,7 @@ Warnings:
 Note	1003	select * from t0,t3 where t3.a=112233
 connection con1;
 a	a
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 drop table t3;
 #
 # MDEV-270: SHOW EXPLAIN: server crashes in JOIN::print_explain on a query with 
@@ -530,7 +530,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 2	SUBQUERY	t2	const	PRIMARY	PRIMARY	4	const	1	
 3	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_do_select';
+SET debug_dbug='+d,show_explain_probe_do_select';
 SELECT * FROM t2 WHERE a = 
 (SELECT MAX(a) FROM t2 
 WHERE pk= (SELECT MAX(pk) FROM t2 WHERE pk = 3)
@@ -552,7 +552,7 @@ pk	a
 6	7
 7	7
 9	7
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 drop table t2;
 #
 # MDEV-273: SHOW EXPLAIN: server crashes in JOIN::print_explain on a query with impossible WHERE
@@ -584,7 +584,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	87	Using join buffer (flat, BNL join)
 2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_do_select';
+SET debug_dbug='+d,show_explain_probe_do_select';
 SELECT count(*) FROM t2, t3
 WHERE a1 < ALL ( 
 SELECT a1 FROM t2
@@ -605,7 +605,7 @@ WHERE a1 IN ( SELECT a1 FROM t2, t4 )
 connection con1;
 count(*)
 1740
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 drop table t2, t3, t4;
 #
 # MDEV-275: SHOW EXPLAIN: server crashes in JOIN::print_explain with IN subquery and aggregate function
@@ -615,7 +615,7 @@ INSERT INTO t2 VALUES
 (1,5),(2,4),(3,6),(4,9),(5,2),(6,8),(7,4),(8,8),(9,0),(10,43),
 (11,23),(12,3),(13,45),(14,16),(15,2),(16,33),(17,2),(18,5),(19,9),(20,2);
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_end';
+SET debug_dbug='+d,show_explain_probe_join_exec_end';
 SELECT * FROM t2 WHERE (5, 78) IN (SELECT `a1`, MAX(`a1`) FROM t2 GROUP BY `a1`);
 connection default;
 show explain for $thr2;
@@ -627,7 +627,7 @@ Warnings:
 Note	1003	SELECT * FROM t2 WHERE (5, 78) IN (SELECT `a1`, MAX(`a1`) FROM t2 GROUP BY `a1`)
 connection con1;
 pk	a1
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 DROP TABLE t2;
 DROP TABLE t1;
 #
@@ -636,7 +636,7 @@ DROP TABLE t1;
 CREATE TABLE t1(a INT, KEY(a));
 INSERT INTO t1 VALUES (3),(1),(5),(1);
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 SELECT 'test' FROM t1 WHERE a=1;
 connection default;
 show explain for $thr2;
@@ -648,7 +648,7 @@ connection con1;
 test
 test
 test
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 DROP TABLE t1;
 #
 # MDEV-299: SHOW EXPLAIN: Plan produced by SHOW EXPLAIN changes back and forth during query execution
@@ -666,7 +666,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	A	ALL	NULL	NULL	NULL	NULL	100	Using where
 1	SIMPLE	B	ALL	key1	NULL	NULL	NULL	100	Range checked for each record (index map: 0x1)
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_test_if_quick_select';
+SET debug_dbug='+d,show_explain_probe_test_if_quick_select';
 select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND B.col2 + 1 < 100;
 connection default;
 show explain for $thr2;
@@ -696,7 +696,7 @@ Note	1003	select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND
 connection con1;
 count(*)
 212
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 drop table t1;
 #
 # MDEV-297: SHOW EXPLAIN: Server gets stuck until timeout occurs while
@@ -705,7 +705,7 @@ drop table t1;
 CREATE TABLE t1(a INT, b INT, c INT, KEY(a), KEY(b), KEY(c));
 INSERT INTO t1 (a) VALUES (3),(1),(5),(1);
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 SHOW INDEX FROM t1;
 connection default;
 show explain for $thr2;
@@ -718,7 +718,7 @@ Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_par
 t1	1	a	1	a	A	NULL	NULL	NULL	YES	BTREE		
 t1	1	b	1	b	A	NULL	NULL	NULL	YES	BTREE		
 t1	1	c	1	c	A	NULL	NULL	NULL	YES	BTREE		
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 DROP TABLE t1;
 #
 # MDEV-324: SHOW EXPLAIN: Plan produced by SHOW EXPLAIN for a query with TEMPTABLE view 
@@ -731,7 +731,7 @@ EXPLAIN SELECT a + 1 FROM v1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	
 2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	2	
-set debug_dbug='+d,show_explain_probe_join_tab_preread';
+SET debug_dbug='+d,show_explain_probe_join_tab_preread';
 set @show_explain_probe_select_id=1;
 SELECT a + 1 FROM v1;
 connection default;
@@ -745,7 +745,7 @@ connection con1;
 a + 1
 2
 3
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 DROP VIEW v1;
 DROP TABLE t1;
 #
@@ -761,7 +761,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
-set debug_dbug='+d,show_explain_probe_union_read';
+SET debug_dbug='+d,show_explain_probe_union_read';
 SELECT a FROM t1 WHERE a IN ( SELECT 1+SLEEP(0.01) UNION SELECT 2 );
 connection default;
 show explain for $thr2;
@@ -782,7 +782,7 @@ Warnings:
 Note	1003	SELECT a FROM t1 WHERE a IN ( SELECT 1+SLEEP(0.01) UNION SELECT 2 )
 connection con1;
 a
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 DROP TABLE t1;
 #
 # MDEV-327: SHOW EXPLAIN: Different select_type in plans produced by SHOW EXPLAIN 
@@ -805,7 +805,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 3	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	20	
 3	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	20	Using where
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 SELECT * FROM t1, ( SELECT * FROM t2 ) AS alias
 WHERE a < ALL ( SELECT b FROM t1, t2 WHERE a = b );
 connection default;
@@ -820,7 +820,7 @@ Note	1003	SELECT * FROM t1, ( SELECT * FROM t2 ) AS alias
 WHERE a < ALL ( SELECT b FROM t1, t2 WHERE a = b )
 connection con1;
 a	b
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 DROP TABLE t1, t2;
 # 
 #  Test that SHOW EXPLAIN will print 'Distinct'.
@@ -842,7 +842,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	PRIMARY	PRIMARY	4	NULL	4	Using index; Using temporary
 1	SIMPLE	t3	ref	a	a	5	test.t1.a	7	Using index; Distinct
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 select distinct t1.a from t1,t3 where t1.a=t3.a;
 connection default;
 show explain for $thr2;
@@ -855,7 +855,7 @@ connection con1;
 a
 1
 2
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 drop table t1,t3,t4;
 #
 # ----------  SHOW EXPLAIN and permissions -----------------
@@ -869,7 +869,7 @@ connection con1;
 #  First, make sure that user 'test2' cannot do SHOW EXPLAIN on us
 #
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 select * from t0 where a < 3;
 connection default;
 connection con2;
@@ -886,14 +886,14 @@ a
 0
 1
 2
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 #
 # Check that user test2 can do SHOW EXPLAIN on its own queries 
 #
 connect  con3, localhost, test2,,;
 connection con2;
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 select * from t0 where a < 3;
 connection con1;
 connection con3;
@@ -916,9 +916,9 @@ disconnect con2;
 grant process on *.* to test2@localhost;
 connect  con2, localhost, test2,,;
 connection con1;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 select * from t0 where a < 3;
 connection default;
 connection con2;
@@ -932,7 +932,7 @@ a
 0
 1
 2
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 revoke all privileges on test.* from test2@localhost;
 drop user test2@localhost;
 disconnect con2;
@@ -1009,7 +1009,7 @@ ORDER BY b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index_merge	a,b	a,b	5,5	NULL	8	Using sort_union(a,b); Using where; Using filesort
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 SELECT a+SLEEP(0.01) FROM t1
 WHERE a IN ( 255, 0 ) OR b BETWEEN 6 AND 129
 ORDER BY b;
@@ -1030,9 +1030,9 @@ a+SLEEP(0.01)
 0
 0
 0
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_do_select';
+SET debug_dbug='+d,show_explain_probe_do_select';
 SELECT a+SLEEP(0.01) FROM t1
 WHERE a IN ( 255, 0 ) OR b BETWEEN 6 AND 129
 ORDER BY b;
@@ -1053,7 +1053,7 @@ a+SLEEP(0.01)
 0
 0
 0
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 drop table t1;
 # 
 # MDEV-298: SHOW EXPLAIN: Plan returned by SHOW EXPLAIN only contains 
@@ -1067,7 +1067,7 @@ EXPLAIN SELECT a FROM t1 GROUP BY a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4112	Using temporary; Using filesort
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 SELECT a FROM t1 GROUP BY a;
 connection default;
 show explain for $thr2;
@@ -1093,7 +1093,7 @@ a
 14
 15
 16
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 drop table t1;
 #
 # MDEV-408: SHOW EXPLAIN: Some values are chopped off in SHOW EXPLAIN output
@@ -1107,7 +1107,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
 2	DEPENDENT SUBQUERY	t2	index_subquery	PRIMARY,c	c	5	func	1	Using index; Using where
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 SELECT SUM(a + SLEEP(0.1)) FROM t1 WHERE a IN ( SELECT c FROM t2 WHERE d < b ) OR b < 's';
 connection default;
 show explain for $thr2;
@@ -1119,7 +1119,7 @@ Note	1003	SELECT SUM(a + SLEEP(0.1)) FROM t1 WHERE a IN ( SELECT c FROM t2 WHERE
 connection con1;
 SUM(a + SLEEP(0.1))
 7862
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 drop table t1, t2;
 #
 # MDEV-412: SHOW EXPLAIN: Server crashes in JOIN::print_explain on a query with inner join and ORDER BY the same column twice
@@ -1157,7 +1157,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	range	b	b	6	NULL	107	Using where; Using index
 1	SIMPLE	t3	ref	PRIMARY	PRIMARY	5	test.t1.b	1	Using index
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_do_select';
+SET debug_dbug='+d,show_explain_probe_do_select';
 SELECT b AS field1, b AS field2 FROM t1, t2, t3 WHERE d = b ORDER BY field1, field2;
 connection default;
 show explain for $thr2;
@@ -1169,7 +1169,7 @@ Warnings:
 Note	1003	SELECT b AS field1, b AS field2 FROM t1, t2, t3 WHERE d = b ORDER BY field1, field2
 connection con1;
 field1	field2
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 DROP TABLE t1,t2,t3;
 #
 # MDEV-423: SHOW EXPLAIN: 'Using where' for a subquery is shown in EXPLAIN, but not in SHOW EXPLAIN output
@@ -1190,7 +1190,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	20	
 3	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	20	Using where
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 SELECT max(a+b+c) FROM t1 AS alias1, ( SELECT * FROM t2 ) AS alias 
 WHERE EXISTS ( SELECT * FROM t3 WHERE b = c )  OR a <= 10;
 connection default;
@@ -1205,7 +1205,7 @@ WHERE EXISTS ( SELECT * FROM t3 WHERE b = c )  OR a <= 10
 connection con1;
 max(a+b+c)
 279
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 DROP TABLE t1,t2,t3;
 #
 # MDEV-416: Server crashes in SQL_SELECT::cleanup on EXPLAIN with SUM ( DISTINCT ) in a non-correlated subquery (5.5-show-explain tree)
@@ -1231,7 +1231,7 @@ select hex('ãû');
 hex('ãû')
 E3FB
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 select * from t0 where length('ãû') = a;
 connection default;
 set names utf8;
@@ -1244,7 +1244,7 @@ set names default;
 connection con1;
 a
 2
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 set names default;
 #
 # MDEV-462: SHOW EXPLAIN: Assertion `table_list->table' fails in find_field_in_table_ref if FOR contains a non-numeric value
@@ -1270,7 +1270,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 3	DEPENDENT SUBQUERY	t1	ALL	a	NULL	NULL	NULL	2	Range checked for each record (index map: 0x1)
 4	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 SELECT SUM(b) FROM ( SELECT * FROM t1 ) AS alias1, t2 
 WHERE b <= ANY ( 
 SELECT a FROM t1 
@@ -1290,7 +1290,7 @@ WHERE a = b + SLEEP(0.2) OR a >= ( SELECT SUM(b) FROM t2 ))
 connection con1;
 SUM(b)
 0
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 DROP TABLE t1,t2;
 drop table t0;
 #
@@ -1302,7 +1302,7 @@ create table t1 (a int, b int);
 insert into t1 select a,a from t0;
 create table t2 as select * from t1;
 set @show_explain_probe_select_id=2;
-set debug_dbug='+d,show_explain_probe_best_ext_lim_search';
+SET debug_dbug='+d,show_explain_probe_best_ext_lim_search';
 explain 
 select * from t0 
 where not exists ( select 1 from t1, t2 where t1.b=t2.b and t2.a=t0.a) and a is null;
diff --git a/mysql-test/main/show_explain.test b/mysql-test/main/show_explain.test
index 6647ca07eba..6f49b9cd301 100644
--- a/mysql-test/main/show_explain.test
+++ b/mysql-test/main/show_explain.test
@@ -16,7 +16,7 @@ SET @old_debug= @@session.debug;
 # is that we use the following commands for synchronization:
 #
 #    set @show_explain_probe_select_id=1;
-#    set debug_dbug='d,show_explain_probe_join_exec_start';
+#    SET debug_dbug='d,show_explain_probe_join_exec_start';
 #    send select count(*) from t1 where a < 100000;
 #
 # When ran with mysqltest_embedded, this translates into: 
@@ -76,7 +76,7 @@ let $wait_condition= select State='show_explain_trap' from information_schema.pr
 #
 connection con1;
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 send select count(*) from t1 where a < 100000;
 
 connection default;
@@ -104,109 +104,109 @@ evalp show explain for $thr2;
 connection con1;
 reap;
 set optimizer_switch= @show_expl_tmp;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 --echo # UNION, first branch 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 send explain select a from t0 A union select a+1 from t0 B;
 connection default;
 --source include/wait_condition.inc
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 
 --echo # UNION, second branch
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 send explain select a from t0 A union select a+1 from t0 B;
 connection default;
 --source include/wait_condition.inc
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 
 --echo # Uncorrelated  subquery, select
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 send select a, (select max(a) from t0 B) from t0 A where a<1;
 connection default;
 --source include/wait_condition.inc
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 
 --echo # Uncorrelated  subquery, explain
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 send explain select a, (select max(a) from t0 B) from t0 A where a<1;
 connection default;
 --source include/wait_condition.inc
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 --echo # correlated  subquery, select
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
 connection default;
 --source include/wait_condition.inc
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 --echo # correlated  subquery, explain
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
 connection default;
 --source include/wait_condition.inc
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 --echo # correlated  subquery, select, while inside the subquery
 set @show_explain_probe_select_id=2; # <---
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
 connection default;
 --source include/wait_condition.inc
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 --echo # correlated  subquery, explain, while inside the subquery
 set @show_explain_probe_select_id=2;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
 connection default;
 --source include/wait_condition.inc
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 --echo # correlated  subquery, explain, while inside the subquery
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_end';
+SET debug_dbug='+d,show_explain_probe_join_exec_end';
 send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
 connection default;
 --source include/wait_condition.inc
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 # TODO: explain in the parent subuqery when the un-correlated child has been
 # run (and have done irreversible cleanups)
@@ -219,7 +219,7 @@ set debug_dbug=@old_debug;
 --echo #   I've found experimentally that select_id==2 here...
 --echo # 
 set @show_explain_probe_select_id=2;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 send set @foo= (select max(a) from t0 where sin(a) >0);
 connection default;
 --source include/wait_condition.inc
@@ -229,14 +229,14 @@ evalp kill query $thr2;
 connection con1;
 --error ER_QUERY_INTERRUPTED
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 --echo #
 --echo # Attempt SHOW EXPLAIN for an UPDATE
 --echo #
 create table t2 as select a as a, a as dummy from t0 limit 2;
 set @show_explain_probe_select_id=2;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 send update t2 set dummy=0 where (select max(a) from t0 where t2.a + t0.a <3) >3 ;
 connection default;
 --source include/wait_condition.inc
@@ -248,14 +248,14 @@ evalp show explain for $thr2;
 connection con1;
 reap;
 drop table t2;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 --echo #
 --echo # Attempt SHOW EXPLAIN for a DELETE (UPD: now works)
 --echo # 
 create table t2 as select a as a, a as dummy from t0 limit 2;
 set @show_explain_probe_select_id=2;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 send delete from t2 where (select max(a) from t0 where t2.a + t0.a <3) >3 ;
 connection default;
 --source include/wait_condition.inc
@@ -267,14 +267,14 @@ evalp show explain for $thr2;
 connection con1;
 reap;
 drop table t2;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 --echo #
 --echo # Multiple SHOW EXPLAIN calls for one select 
 --echo # 
 create table t2 as select a as a, a as dummy from t0 limit 3;
 set @show_explain_probe_select_id=2;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 send select t2.a, ((select max(a) from t0 where t2.a + t0.a <3) >3) as SUBQ from t2;
 connection default;
 --source include/wait_condition.inc
@@ -286,14 +286,14 @@ evalp show explain for $thr2;
 connection con1;
 reap;
 drop table t2;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 --echo #
 --echo # SHOW EXPLAIN for SELECT ... ORDER BY with "Using filesort"
 --echo #
 explain select * from t0 order by a;
 
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 set @show_explain_probe_select_id=1;
 send select * from t0 order by a; 
 connection default;
@@ -301,7 +301,7 @@ connection default;
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 --echo #
 --echo # SHOW EXPLAIN for SELECT ... with "Using temporary"
@@ -310,7 +310,7 @@ connection default;
 explain select distinct a from t0;
 connection con1;
 
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 set @show_explain_probe_select_id=1;
 send select distinct a from t0; 
 connection default;
@@ -318,7 +318,7 @@ connection default;
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 --echo #
 --echo # SHOW EXPLAIN for SELECT ... with "Using temporary; Using filesort"
@@ -327,7 +327,7 @@ connection default;
 explain select distinct a from t0;
 connection con1;
 
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 set @show_explain_probe_select_id=1;
 
 send select distinct a from t0; 
@@ -336,7 +336,7 @@ connection default;
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 --echo #
 --echo # MDEV-238: SHOW EXPLAIN: Server crashes in JOIN::print_explain with FROM subquery and GROUP BY
@@ -345,7 +345,7 @@ CREATE TABLE t2 ( a INT );
 INSERT INTO t2 VALUES (1),(2),(1),(4),(2);
 explain SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a;
 
-set debug_dbug='+d,show_explain_in_find_all_keys';
+SET debug_dbug='+d,show_explain_in_find_all_keys';
 send SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a;
 
 connection default;
@@ -356,7 +356,7 @@ connection default;
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 DROP TABLE t2;
 
 
@@ -372,7 +372,7 @@ INSERT INTO t2 VALUES (1),(2),(1),(4),(2);
 EXPLAIN EXTENDED SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a ;
 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_end';
+SET debug_dbug='+d,show_explain_probe_join_exec_end';
 send EXPLAIN EXTENDED SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a ;
 
 connection default;
@@ -380,7 +380,7 @@ connection default;
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 DROP TABLE t2;
 
 
@@ -396,7 +396,7 @@ INSERT INTO t2 VALUES (4),(5),(6),(7),(8),(9);
 explain SELECT * FROM v1, t2;
 
 set @show_explain_probe_select_id=2;
-set debug_dbug='+d,show_explain_probe_join_exec_end';
+SET debug_dbug='+d,show_explain_probe_join_exec_end';
 send SELECT * FROM v1, t2;
 
 connection default;
@@ -407,7 +407,7 @@ evalp kill query $thr2;
 connection con1;
 --error ER_QUERY_INTERRUPTED
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 DROP VIEW v1;
 DROP TABLE t2, t3;
 
@@ -415,21 +415,21 @@ DROP TABLE t2, t3;
 --echo # MDEV-267: SHOW EXPLAIN: Server crashes in JOIN::print_explain on most of queries
 --echo #
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_end';
+SET debug_dbug='+d,show_explain_probe_join_exec_end';
 send select sleep(1);
 connection default;
 --source include/wait_condition.inc
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 
 --echo #
 --echo # Same as above, but try another reason for JOIN to be degenerate
 --echo #
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_end';
+SET debug_dbug='+d,show_explain_probe_join_exec_end';
 send select * from t0 where 1>10;
 connection default;
 --source include/wait_condition.inc
@@ -437,7 +437,7 @@ connection default;
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 --echo #
 --echo # Same as above, but try another reason for JOIN to be degenerate (2)
@@ -445,7 +445,7 @@ set debug_dbug=@old_debug;
 create table t3(a int primary key);
 insert into t3 select a from t0;
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_end';
+SET debug_dbug='+d,show_explain_probe_join_exec_end';
 send select * from t0,t3 where t3.a=112233;
 connection default;
 --source include/wait_condition.inc
@@ -453,7 +453,7 @@ connection default;
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 drop table t3;
 
 --echo #
@@ -472,7 +472,7 @@ explain SELECT * FROM t2 WHERE a =
        );
 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_do_select';
+SET debug_dbug='+d,show_explain_probe_do_select';
 send SELECT * FROM t2 WHERE a = 
        (SELECT MAX(a) FROM t2 
         WHERE pk= (SELECT MAX(pk) FROM t2 WHERE pk = 3)
@@ -482,7 +482,7 @@ connection default;
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 drop table t2;
 
 
@@ -515,7 +515,7 @@ WHERE a1 < ALL (
 );
 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_do_select';
+SET debug_dbug='+d,show_explain_probe_do_select';
 send
 SELECT count(*) FROM t2, t3
 WHERE a1 < ALL ( 
@@ -528,7 +528,7 @@ connection default;
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 drop table t2, t3, t4;
 
 --echo #
@@ -540,7 +540,7 @@ INSERT INTO t2 VALUES
   (11,23),(12,3),(13,45),(14,16),(15,2),(16,33),(17,2),(18,5),(19,9),(20,2);
 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_end';
+SET debug_dbug='+d,show_explain_probe_join_exec_end';
 send
   SELECT * FROM t2 WHERE (5, 78) IN (SELECT `a1`, MAX(`a1`) FROM t2 GROUP BY `a1`);
 connection default;
@@ -549,7 +549,7 @@ connection default;
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 DROP TABLE t2;
 DROP TABLE t1;
@@ -561,7 +561,7 @@ CREATE TABLE t1(a INT, KEY(a));
 INSERT INTO t1 VALUES (3),(1),(5),(1);
 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 
 send SELECT 'test' FROM t1 WHERE a=1;
 connection default;
@@ -569,7 +569,7 @@ connection default;
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 DROP TABLE t1;
 
@@ -593,7 +593,7 @@ set join_cache_level=0;
 explain select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND B.col2 + 1 < 100;
 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_test_if_quick_select';
+SET debug_dbug='+d,show_explain_probe_test_if_quick_select';
 
 send 
 select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND B.col2 + 1 < 100;
@@ -610,7 +610,7 @@ evalp show explain for $thr2;
 connection con1;
 reap;
 
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 drop table t1;
 
 --echo #
@@ -621,7 +621,7 @@ CREATE TABLE t1(a INT, b INT, c INT, KEY(a), KEY(b), KEY(c));
 INSERT INTO t1 (a) VALUES (3),(1),(5),(1);
 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 
 send SHOW INDEX FROM t1;
 connection default;
@@ -629,7 +629,7 @@ connection default;
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 DROP TABLE t1;
 
@@ -643,7 +643,7 @@ CREATE ALGORITHM=TEMPTABLE VIEW v1 AS SELECT * FROM t1;
 
 EXPLAIN SELECT a + 1 FROM v1;
 
-set debug_dbug='+d,show_explain_probe_join_tab_preread';
+SET debug_dbug='+d,show_explain_probe_join_tab_preread';
 set @show_explain_probe_select_id=1;
 
 send
@@ -653,7 +653,7 @@ connection default;
 evalp show explain for $thr2;
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 DROP VIEW v1;
 DROP TABLE t1;
@@ -669,7 +669,7 @@ INSERT INTO t1 VALUES (4),(6);
 EXPLAIN 
 SELECT a FROM t1 WHERE a IN ( SELECT 1+SLEEP(0.01) UNION SELECT 2 );
 
-set debug_dbug='+d,show_explain_probe_union_read';
+SET debug_dbug='+d,show_explain_probe_union_read';
 send
 SELECT a FROM t1 WHERE a IN ( SELECT 1+SLEEP(0.01) UNION SELECT 2 );
 
@@ -683,7 +683,7 @@ evalp show explain for $thr2;
 connection con1;
 reap;
 
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 DROP TABLE t1;
 
 --echo #
@@ -705,7 +705,7 @@ SELECT * FROM t1, ( SELECT * FROM t2 ) AS alias
 WHERE a < ALL ( SELECT b FROM t1, t2 WHERE a = b );
 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 --send
 SELECT * FROM t1, ( SELECT * FROM t2 ) AS alias
 WHERE a < ALL ( SELECT b FROM t1, t2 WHERE a = b );
@@ -716,7 +716,7 @@ evalp show explain for $thr2;
 
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 DROP TABLE t1, t2;
 
 --echo # 
@@ -739,7 +739,7 @@ insert into t3 select * from t4;
 explain select distinct t1.a from t1,t3 where t1.a=t3.a;
 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 --send
 select distinct t1.a from t1,t3 where t1.a=t3.a;
 connection default;
@@ -748,7 +748,7 @@ evalp show explain for $thr2;
 
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 drop table t1,t3,t4;
 
@@ -758,7 +758,7 @@ drop table t1,t3,t4;
 create user test2@localhost;
 grant ALL on test.* to test2@localhost;
 
-# Give the user SUPER privilege so it can set debug_dbug variable.
+# Give the user SUPER privilege so it can SET debug_dbug variable.
 grant super on *.* to test2@localhost;
 connect (con2, localhost, test2,,);
 connection con1;
@@ -767,7 +767,7 @@ connection con1;
 --echo #  First, make sure that user 'test2' cannot do SHOW EXPLAIN on us
 --echo #
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 send
 select * from t0 where a < 3;
 
@@ -783,7 +783,7 @@ evalp show explain for $thr2;
 
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 --echo #
 --echo # Check that user test2 can do SHOW EXPLAIN on its own queries 
@@ -793,7 +793,7 @@ connect (con3, localhost, test2,,);
 connection con2;
 let $thr_con2=`select connection_id()`;
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 send
 select * from t0 where a < 3;
 
@@ -819,10 +819,10 @@ disconnect con2;
 grant process on *.* to test2@localhost;
 connect (con2, localhost, test2,,);
 connection con1;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 send
 select * from t0 where a < 3;
 
@@ -834,7 +834,7 @@ evalp show explain for $thr2;
 
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 revoke all privileges on test.* from test2@localhost;
 drop user test2@localhost;
@@ -914,7 +914,7 @@ WHERE a IN ( 255, 0 ) OR b BETWEEN 6 AND 129
 ORDER BY b;
 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 --send
 SELECT a+SLEEP(0.01) FROM t1
 WHERE a IN ( 255, 0 ) OR b BETWEEN 6 AND 129
@@ -926,10 +926,10 @@ evalp show explain for $thr2;
 
 connection con1;
 reap;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_do_select';
+SET debug_dbug='+d,show_explain_probe_do_select';
 --send
 SELECT a+SLEEP(0.01) FROM t1
 WHERE a IN ( 255, 0 ) OR b BETWEEN 6 AND 129
@@ -942,7 +942,7 @@ evalp show explain for $thr2;
 connection con1;
 reap;
 
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 drop table t1;
 
@@ -958,7 +958,7 @@ INSERT INTO t1 SELECT t11.a FROM t1 t11, t1 t12, t1 t13;
 EXPLAIN SELECT a FROM t1 GROUP BY a;
 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 --send
 SELECT a FROM t1 GROUP BY a;
 
@@ -969,7 +969,7 @@ evalp show explain for $thr2;
 connection con1;
 reap;
 
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 drop table t1;
 
@@ -985,7 +985,7 @@ INSERT INTO t2 VALUES (86,'English'),(87,'Russian');
 explain SELECT SUM(a + SLEEP(0.1)) FROM t1 WHERE a IN ( SELECT c FROM t2 WHERE d < b ) OR b < 's';
 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 --send
 SELECT SUM(a + SLEEP(0.1)) FROM t1 WHERE a IN ( SELECT c FROM t2 WHERE d < b ) OR b < 's';
 
@@ -996,7 +996,7 @@ evalp show explain for $thr2;
 connection con1;
 reap;
 
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 drop table t1, t2;
 
 --echo #
@@ -1035,7 +1035,7 @@ explain
 SELECT b AS field1, b AS field2 FROM t1, t2, t3 WHERE d = b ORDER BY field1, field2;
 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_do_select';
+SET debug_dbug='+d,show_explain_probe_do_select';
 
 send
 SELECT b AS field1, b AS field2 FROM t1, t2, t3 WHERE d = b ORDER BY field1, field2;
@@ -1047,7 +1047,7 @@ evalp show explain for $thr2;
 connection con1;
 reap;
 
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 
 DROP TABLE t1,t2,t3;
 
@@ -1071,7 +1071,7 @@ SELECT max(a+b+c) FROM t1 AS alias1, ( SELECT * FROM t2 ) AS alias
 WHERE EXISTS ( SELECT * FROM t3 WHERE b = c )  OR a <= 10;
 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 
 send
 SELECT max(a+b+c) FROM t1 AS alias1, ( SELECT * FROM t2 ) AS alias 
@@ -1084,7 +1084,7 @@ evalp show explain for $thr2;
 connection con1;
 reap;
 
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 DROP TABLE t1,t2,t3;
 
 --echo #
@@ -1111,7 +1111,7 @@ select charset('ãû');
 select hex('ãû');
 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 
 send
 select * from t0 where length('ãû') = a;
@@ -1126,7 +1126,7 @@ connection con1;
 # The constant should be two letters, the last looking like 'bl'
 reap;
 
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 set names default;
 
 --echo #
@@ -1153,7 +1153,7 @@ WHERE b <= ANY (
 
 
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_join_exec_start';
+SET debug_dbug='+d,show_explain_probe_join_exec_start';
 
 send
 SELECT SUM(b) FROM ( SELECT * FROM t1 ) AS alias1, t2 
@@ -1168,7 +1168,7 @@ evalp show explain for $thr2;
 connection con1;
 reap;
 
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 DROP TABLE t1,t2;
 drop table t0;
 
@@ -1184,7 +1184,7 @@ insert into t1 select a,a from t0;
 create table t2 as select * from t1;
 
 set @show_explain_probe_select_id=2;
-set debug_dbug='+d,show_explain_probe_best_ext_lim_search';
+SET debug_dbug='+d,show_explain_probe_best_ext_lim_search';
 send
 explain 
 select * from t0 
diff --git a/mysql-test/main/show_explain_non_select.result b/mysql-test/main/show_explain_non_select.result
index 6076a848e22..8d96056ca91 100644
--- a/mysql-test/main/show_explain_non_select.result
+++ b/mysql-test/main/show_explain_non_select.result
@@ -14,7 +14,7 @@ from t0 A, t0 B, t0 C;
 # Test SHOW EXPLAIN for single-table DELETE
 #
 connection con2;
-set debug_dbug='+d,show_explain_probe_delete_exec_start';
+SET debug_dbug='+d,show_explain_probe_delete_exec_start';
 delete from t1 where a<10 and b+1>1000;
 connection default;
 show explain for $thr2;
@@ -27,7 +27,7 @@ connection con2;
 # Test SHOW EXPLAIN for multi-table DELETE
 #
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_do_select';
+SET debug_dbug='+d,show_explain_probe_do_select';
 delete t1 from t1, t0 where t0.a=t1.a and t1.b +1 > 1000;
 connection default;
 show explain for $thr2;
@@ -41,7 +41,7 @@ connection con2;
 # Test SHOW EXPLAIN for single-table UPDATE
 #
 connection con2;
-set debug_dbug='+d,show_explain_probe_update_exec_start';
+SET debug_dbug='+d,show_explain_probe_update_exec_start';
 update t1 set filler='filler-data-2' where a<10 and b+1>1000;
 connection default;
 show explain for $thr2;
@@ -51,5 +51,5 @@ Warnings:
 Note	1003	update t1 set filler='filler-data-2' where a<10 and b+1>1000
 connection con2;
 drop table t0,t1;
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 set debug_sync='RESET';
diff --git a/mysql-test/main/show_explain_non_select.test b/mysql-test/main/show_explain_non_select.test
index 21b16739141..505e9296222 100644
--- a/mysql-test/main/show_explain_non_select.test
+++ b/mysql-test/main/show_explain_non_select.test
@@ -38,7 +38,7 @@ let $wait_condition= select State='show_explain_trap' from information_schema.pr
 --echo # Test SHOW EXPLAIN for single-table DELETE
 --echo #
 connection con2;
-set debug_dbug='+d,show_explain_probe_delete_exec_start';
+SET debug_dbug='+d,show_explain_probe_delete_exec_start';
 send delete from t1 where a<10 and b+1>1000;
 
 connection default;
@@ -51,7 +51,7 @@ reap;
 --echo # Test SHOW EXPLAIN for multi-table DELETE
 --echo #
 set @show_explain_probe_select_id=1;
-set debug_dbug='+d,show_explain_probe_do_select';
+SET debug_dbug='+d,show_explain_probe_do_select';
 send delete t1 from t1, t0 where t0.a=t1.a and t1.b +1 > 1000;
 connection default;
 --source include/wait_condition.inc
@@ -63,7 +63,7 @@ reap;
 --echo # Test SHOW EXPLAIN for single-table UPDATE
 --echo #
 connection con2;
-set debug_dbug='+d,show_explain_probe_update_exec_start';
+SET debug_dbug='+d,show_explain_probe_update_exec_start';
 send update t1 set filler='filler-data-2' where a<10 and b+1>1000;
 
 connection default;
@@ -74,5 +74,5 @@ reap;
 
 drop table t0,t1;
 
-set debug_dbug=@old_debug;
+SET debug_dbug=@old_debug;
 set debug_sync='RESET';
diff --git a/mysql-test/main/show_explain_ps.result b/mysql-test/main/show_explain_ps.result
index 69ee2cab31d..1c3be0d5953 100644
--- a/mysql-test/main/show_explain_ps.result
+++ b/mysql-test/main/show_explain_ps.result
@@ -17,7 +17,8 @@ connection con1;
 connection default;
 connection con1;
 set @show_explain_probe_select_id=1;
-set debug_dbug='d,show_explain_probe_join_exec_start';
+SET @saved_dbug = @@SESSION.debug_dbug;
+SET debug_dbug='d,show_explain_probe_join_exec_start';
 select count(*) from t0 where a < 100000;
 connection default;
 show explain for $thr2;
@@ -28,7 +29,7 @@ Note	1003	select count(*) from t0 where a < 100000
 connection con1;
 count(*)
 10
-set debug_dbug='';
+SET debug_dbug= @saved_dbug;
 select event_name
 from
 performance_schema.events_stages_history_long join
diff --git a/mysql-test/main/show_explain_ps.test b/mysql-test/main/show_explain_ps.test
index 13cd1538143..cbff0f50f96 100644
--- a/mysql-test/main/show_explain_ps.test
+++ b/mysql-test/main/show_explain_ps.test
@@ -38,7 +38,8 @@ let $wait_condition= select State='show_explain_trap' from information_schema.pr
 #
 connection con1;
 set @show_explain_probe_select_id=1;
-set debug_dbug='d,show_explain_probe_join_exec_start';
+SET @saved_dbug = @@SESSION.debug_dbug;
+SET debug_dbug='d,show_explain_probe_join_exec_start';
 send select count(*) from t0 where a < 100000;
 
 connection default;
@@ -47,7 +48,7 @@ evalp show explain for $thr2;
 connection con1;
 reap;
 
-set debug_dbug='';
+SET debug_dbug= @saved_dbug;
 
 evalp select event_name
         from
diff --git a/mysql-test/main/slowlog_enospace-10508.result b/mysql-test/main/slowlog_enospace-10508.result
index f39bfa2f00e..66fb19eed6a 100644
--- a/mysql-test/main/slowlog_enospace-10508.result
+++ b/mysql-test/main/slowlog_enospace-10508.result
@@ -3,7 +3,8 @@ create table t1 (a int, b int) engine=memory;
 insert t1 select seq, seq+1 from seq_1_to_1000;
 set global general_log=0;
 set global log_queries_not_using_indexes=1;
-set debug_dbug='+d,simulate_file_write_error';
+SET @saved_dbug = @@SESSION.debug_dbug;
+SET debug_dbug='+d,simulate_file_write_error';
 select * from t1 where a>10;
 select * from t1 where a>10;
 select * from t1 where a>10;
@@ -54,7 +55,7 @@ select * from t1 where a>10;
 select * from t1 where a>10;
 select * from t1 where a>10;
 select * from t1 where a>10;
-set debug_dbug='';
+SET debug_dbug= @saved_dbug;
 set global general_log=1;
 set global log_queries_not_using_indexes=default;
 drop table t1;
diff --git a/mysql-test/main/slowlog_enospace-10508.test b/mysql-test/main/slowlog_enospace-10508.test
index b2c26a5984d..74dca21f8ec 100644
--- a/mysql-test/main/slowlog_enospace-10508.test
+++ b/mysql-test/main/slowlog_enospace-10508.test
@@ -9,7 +9,8 @@ create table t1 (a int, b int) engine=memory;
 insert t1 select seq, seq+1 from seq_1_to_1000;
 set global general_log=0;
 set global log_queries_not_using_indexes=1;
-set debug_dbug='+d,simulate_file_write_error';
+SET @saved_dbug = @@SESSION.debug_dbug;
+SET debug_dbug='+d,simulate_file_write_error';
 --disable_result_log
 --let $run= 50
 while ($run)
@@ -18,7 +19,7 @@ while ($run)
     dec $run;
 }
 --enable_result_log
-set debug_dbug='';
+SET debug_dbug= @saved_dbug;
 set global general_log=1;
 set global log_queries_not_using_indexes=default;
 drop table t1;
diff --git a/mysql-test/main/stat_tables-enospc.result b/mysql-test/main/stat_tables-enospc.result
index 943cbca6bc5..9ac24a2af99 100644
--- a/mysql-test/main/stat_tables-enospc.result
+++ b/mysql-test/main/stat_tables-enospc.result
@@ -1,11 +1,12 @@
 call mtr.add_suppression("No space left on device");
 create table t1 (a varchar(255), b varchar(255), c varchar(255));
 set use_stat_tables=PREFERABLY, optimizer_use_condition_selectivity=3;
-set debug_dbug='+d,simulate_file_write_error';
+SET @saved_dbug = @@SESSION.debug_dbug;
+SET debug_dbug='+d,simulate_file_write_error';
 set @@max_heap_table_size=128*1024;
 analyze table t1;
 Table	Op	Msg_type	Msg_text
 test.t1	analyze	Error	Error writing file 'tmp-file' (Errcode: 28 "No space left on device")
 test.t1	analyze	status	Operation failed
-set debug_dbug='';
+SET debug_dbug= @saved_dbug;
 drop table t1;
diff --git a/mysql-test/main/stat_tables-enospc.test b/mysql-test/main/stat_tables-enospc.test
index 932b2bde302..fe8fe3590ae 100644
--- a/mysql-test/main/stat_tables-enospc.test
+++ b/mysql-test/main/stat_tables-enospc.test
@@ -16,9 +16,10 @@ while ($i) {
 }
 --enable_query_log
 set use_stat_tables=PREFERABLY, optimizer_use_condition_selectivity=3;
-set debug_dbug='+d,simulate_file_write_error';
+SET @saved_dbug = @@SESSION.debug_dbug;
+SET debug_dbug='+d,simulate_file_write_error';
 set @@max_heap_table_size=128*1024;
 --replace_regex /'.*'/'tmp-file'/
 analyze table t1;
-set debug_dbug='';
+SET debug_dbug= @saved_dbug;
 drop table t1;
diff --git a/mysql-test/main/union_crash-714.result b/mysql-test/main/union_crash-714.result
index 4a51f88b76f..371be1e03d0 100644
--- a/mysql-test/main/union_crash-714.result
+++ b/mysql-test/main/union_crash-714.result
@@ -1,5 +1,7 @@
 create table t1 (i tinyint);
-set debug_dbug='+d,bug11747970_raise_error';
+SET @saved_dbug = @@SESSION.debug_dbug;
+SET debug_dbug='+d,bug11747970_raise_error';
 insert into t1 (i) select i from t1 union select i from t1;
 ERROR 70100: Query execution was interrupted
 drop table t1;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/main/union_crash-714.test b/mysql-test/main/union_crash-714.test
index 6c31a2202cb..90b849037f2 100644
--- a/mysql-test/main/union_crash-714.test
+++ b/mysql-test/main/union_crash-714.test
@@ -3,7 +3,9 @@
 #
 --source include/have_debug.inc
 create table t1 (i tinyint);
-set debug_dbug='+d,bug11747970_raise_error';
+SET @saved_dbug = @@SESSION.debug_dbug;
+SET debug_dbug='+d,bug11747970_raise_error';
 --error ER_QUERY_INTERRUPTED
 insert into t1 (i) select i from t1 union select i from t1;
 drop table t1;
+SET debug_dbug= @saved_dbug;
\ No newline at end of file
diff --git a/mysql-test/main/warnings_debug.result b/mysql-test/main/warnings_debug.result
index 4cdce7a5feb..3a9d8225795 100644
--- a/mysql-test/main/warnings_debug.result
+++ b/mysql-test/main/warnings_debug.result
@@ -1,5 +1,6 @@
 drop table if exists t1;
 create table t1 (a int primary key) engine=innodb;
+SET @saved_dbug = @@SESSION.debug_dbug;
 SET SESSION debug_dbug="+d,warn_during_ha_commit_trans";
 INSERT INTO t1 VALUES (1);
 Warnings:
@@ -8,3 +9,4 @@ SHOW WARNINGS;
 Level	Code	Message
 Warning	1196	Some non-transactional changed tables couldn't be rolled back
 drop table t1;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/main/warnings_debug.test b/mysql-test/main/warnings_debug.test
index 3055e3894e5..6605daf875d 100644
--- a/mysql-test/main/warnings_debug.test
+++ b/mysql-test/main/warnings_debug.test
@@ -9,6 +9,7 @@ create table t1 (a int primary key) engine=innodb;
 
 # Test that warnings produced during autocommit (after calling
 # set_ok_status()) are still reported to the client.
+SET @saved_dbug = @@SESSION.debug_dbug;
 SET SESSION debug_dbug="+d,warn_during_ha_commit_trans";
 INSERT INTO t1 VALUES (1);
 # The warning will be shown automatically by mysqltest; there was a bug where
@@ -17,3 +18,4 @@ INSERT INTO t1 VALUES (1);
 SHOW WARNINGS;
 
 drop table t1;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/binlog/include/binlog_ioerr.inc b/mysql-test/suite/binlog/include/binlog_ioerr.inc
index 8d1069bacb0..da6fb5ac727 100644
--- a/mysql-test/suite/binlog/include/binlog_ioerr.inc
+++ b/mysql-test/suite/binlog/include/binlog_ioerr.inc
@@ -15,12 +15,13 @@ RESET MASTER;
 
 CREATE TABLE t1 (a INT PRIMARY KEY) ENGINE=innodb;
 INSERT INTO t1 VALUES(0);
+SET @saved_dbug = @@SESSION.debug_dbug;
 SET SESSION debug_dbug='+d,fail_binlog_write_1';
 --error ER_ERROR_ON_WRITE
 INSERT INTO t1 VALUES(1);
 --error ER_ERROR_ON_WRITE
 INSERT INTO t1 VALUES(2);
-SET SESSION debug_dbug='';
+SET SESSION debug_dbug=@saved_dbug;
 INSERT INTO t1 VALUES(3);
 SELECT * FROM t1;
 
diff --git a/mysql-test/suite/binlog/r/binlog_ioerr.result b/mysql-test/suite/binlog/r/binlog_ioerr.result
index 1d3c3d7d12d..e4f00a017ba 100644
--- a/mysql-test/suite/binlog/r/binlog_ioerr.result
+++ b/mysql-test/suite/binlog/r/binlog_ioerr.result
@@ -2,12 +2,13 @@ CALL mtr.add_suppression("Error writing file 'master-bin'");
 RESET MASTER;
 CREATE TABLE t1 (a INT PRIMARY KEY) ENGINE=innodb;
 INSERT INTO t1 VALUES(0);
+SET @saved_dbug = @@SESSION.debug_dbug;
 SET SESSION debug_dbug='+d,fail_binlog_write_1';
 INSERT INTO t1 VALUES(1);
 ERROR HY000: Error writing file 'master-bin' (errno: 28 "No space left on device")
 INSERT INTO t1 VALUES(2);
 ERROR HY000: Error writing file 'master-bin' (errno: 28 "No space left on device")
-SET SESSION debug_dbug='';
+SET SESSION debug_dbug=@saved_dbug;
 INSERT INTO t1 VALUES(3);
 SELECT * FROM t1;
 a
diff --git a/mysql-test/suite/binlog/r/binlog_write_error.result b/mysql-test/suite/binlog/r/binlog_write_error.result
index 2606a9f40b3..6e8a212035a 100644
--- a/mysql-test/suite/binlog/r/binlog_write_error.result
+++ b/mysql-test/suite/binlog/r/binlog_write_error.result
@@ -12,92 +12,109 @@ DROP VIEW IF EXISTS v1, v2;
 #
 # Test injecting binlog write error when executing queries
 #
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 CREATE TABLE t1 (a INT);
 CREATE TABLE t1 (a INT);
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
 INSERT INTO t1 VALUES (1),(2),(3);
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 INSERT INTO t1 VALUES (4),(5),(6);
 INSERT INTO t1 VALUES (4),(5),(6);
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 UPDATE t1 set a=a+1;
 UPDATE t1 set a=a+1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 DELETE FROM t1;
 DELETE FROM t1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 CREATE TRIGGER tr1 AFTER INSERT ON t1 FOR EACH ROW INSERT INTO t1 VALUES (new.a + 100);
 CREATE TRIGGER tr1 AFTER INSERT ON t1 FOR EACH ROW INSERT INTO t1 VALUES (new.a + 100);
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 DROP TRIGGER tr1;
 DROP TRIGGER tr1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 ALTER TABLE t1 ADD (b INT);
 ALTER TABLE t1 ADD (b INT);
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 CREATE VIEW v1 AS SELECT a FROM t1;
 CREATE VIEW v1 AS SELECT a FROM t1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 DROP VIEW v1;
 DROP VIEW v1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 CREATE PROCEDURE p1(OUT rows_cnt INT) SELECT count(*) INTO rows_cnt FROM t1;
 CREATE PROCEDURE p1(OUT rows_cnt INT) SELECT count(*) INTO rows_cnt FROM t1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 DROP PROCEDURE p1;
 DROP PROCEDURE p1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 DROP TABLE t1;
 DROP TABLE t1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 CREATE FUNCTION f1() RETURNS INT return 1;
 CREATE FUNCTION f1() RETURNS INT return 1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 DROP FUNCTION f1;
 DROP FUNCTION f1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 CREATE USER user1;
 CREATE USER user1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 REVOKE ALL PRIVILEGES, GRANT OPTION FROM user1;
 REVOKE ALL PRIVILEGES, GRANT OPTION FROM user1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 DROP USER user1;
 DROP USER user1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
 #
 # Cleanup
 #
diff --git a/mysql-test/suite/binlog_encryption/binlog_ioerr.result b/mysql-test/suite/binlog_encryption/binlog_ioerr.result
index 6b3120b6d89..2823b7050c3 100644
--- a/mysql-test/suite/binlog_encryption/binlog_ioerr.result
+++ b/mysql-test/suite/binlog_encryption/binlog_ioerr.result
@@ -2,12 +2,13 @@ CALL mtr.add_suppression("Error writing file 'master-bin'");
 RESET MASTER;
 CREATE TABLE t1 (a INT PRIMARY KEY) ENGINE=innodb;
 INSERT INTO t1 VALUES(0);
+SET @saved_dbug = @@SESSION.debug_dbug;
 SET SESSION debug_dbug='+d,fail_binlog_write_1';
 INSERT INTO t1 VALUES(1);
 ERROR HY000: Error writing file 'master-bin' (errno: 28 "No space left on device")
 INSERT INTO t1 VALUES(2);
 ERROR HY000: Error writing file 'master-bin' (errno: 28 "No space left on device")
-SET SESSION debug_dbug='';
+SET SESSION debug_dbug=@saved_dbug;
 INSERT INTO t1 VALUES(3);
 SELECT * FROM t1;
 a
diff --git a/mysql-test/suite/binlog_encryption/binlog_write_error.result b/mysql-test/suite/binlog_encryption/binlog_write_error.result
index 2606a9f40b3..6e8a212035a 100644
--- a/mysql-test/suite/binlog_encryption/binlog_write_error.result
+++ b/mysql-test/suite/binlog_encryption/binlog_write_error.result
@@ -12,92 +12,109 @@ DROP VIEW IF EXISTS v1, v2;
 #
 # Test injecting binlog write error when executing queries
 #
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 CREATE TABLE t1 (a INT);
 CREATE TABLE t1 (a INT);
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
 INSERT INTO t1 VALUES (1),(2),(3);
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 INSERT INTO t1 VALUES (4),(5),(6);
 INSERT INTO t1 VALUES (4),(5),(6);
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 UPDATE t1 set a=a+1;
 UPDATE t1 set a=a+1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 DELETE FROM t1;
 DELETE FROM t1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 CREATE TRIGGER tr1 AFTER INSERT ON t1 FOR EACH ROW INSERT INTO t1 VALUES (new.a + 100);
 CREATE TRIGGER tr1 AFTER INSERT ON t1 FOR EACH ROW INSERT INTO t1 VALUES (new.a + 100);
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 DROP TRIGGER tr1;
 DROP TRIGGER tr1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 ALTER TABLE t1 ADD (b INT);
 ALTER TABLE t1 ADD (b INT);
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 CREATE VIEW v1 AS SELECT a FROM t1;
 CREATE VIEW v1 AS SELECT a FROM t1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 DROP VIEW v1;
 DROP VIEW v1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 CREATE PROCEDURE p1(OUT rows_cnt INT) SELECT count(*) INTO rows_cnt FROM t1;
 CREATE PROCEDURE p1(OUT rows_cnt INT) SELECT count(*) INTO rows_cnt FROM t1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 DROP PROCEDURE p1;
 DROP PROCEDURE p1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 DROP TABLE t1;
 DROP TABLE t1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 CREATE FUNCTION f1() RETURNS INT return 1;
 CREATE FUNCTION f1() RETURNS INT return 1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 DROP FUNCTION f1;
 DROP FUNCTION f1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 CREATE USER user1;
 CREATE USER user1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 REVOKE ALL PRIVILEGES, GRANT OPTION FROM user1;
 REVOKE ALL PRIVILEGES, GRANT OPTION FROM user1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug='d,injecting_fault_writing';
 DROP USER user1;
 DROP USER user1;
 ERROR HY000: Error writing file 'master-bin' ((errno: #)
-SET GLOBAL debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
 #
 # Cleanup
 #
diff --git a/mysql-test/suite/binlog_encryption/rpl_checksum.result b/mysql-test/suite/binlog_encryption/rpl_checksum.result
index 41c4cd94aff..22220b8e9fb 100644
--- a/mysql-test/suite/binlog_encryption/rpl_checksum.result
+++ b/mysql-test/suite/binlog_encryption/rpl_checksum.result
@@ -76,6 +76,7 @@ connection master;
 set @@global.binlog_checksum = CRC32;
 insert into t1 values (1) /* will not be applied on slave due to simulation */;
 connection slave;
+set @saved_dbug = @@global.debug_dbug;
 set @@global.debug_dbug='d,simulate_slave_unaware_checksum';
 start slave;
 include/wait_for_slave_io_error.inc [errno=1236]
@@ -83,15 +84,16 @@ Last_IO_Error = 'Got fatal error 1236 from master when reading data from binary
 select count(*) as zero from t1;
 zero
 0
-set @@global.debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
 connection slave;
 include/start_slave.inc
 connection master;
 set @@global.master_verify_checksum = 1;
+set @save_dbug = @@session.debug_dbug;
 set @@session.debug_dbug='d,simulate_checksum_test_failure';
 show binlog events;
 ERROR HY000: Error when executing command SHOW BINLOG EVENTS: Wrong offset or I/O error
-set @@session.debug_dbug='';
+SET debug_dbug= @save_dbug;
 set @@global.master_verify_checksum = default;
 connection slave;
 connection slave;
@@ -99,10 +101,11 @@ include/stop_slave.inc
 connection master;
 create table t2 (a int);
 connection slave;
+set @saved_dbug = @@global.debug_dbug;
 set @@global.debug_dbug='d,simulate_checksum_test_failure';
 start slave io_thread;
 include/wait_for_slave_io_error.inc [errno=1595,1913]
-set @@global.debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
 start slave io_thread;
 include/wait_for_slave_param.inc [Read_Master_Log_Pos]
 set @@global.slave_sql_verify_checksum = 1;
@@ -110,7 +113,7 @@ set @@global.debug_dbug='d,simulate_checksum_test_failure';
 start slave sql_thread;
 include/wait_for_slave_sql_error.inc [errno=1593]
 Last_SQL_Error = 'Error initializing relay log position: I/O error reading event at position 4'
-set @@global.debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
 include/start_slave.inc
 connection master;
 connection slave;
diff --git a/mysql-test/suite/binlog_encryption/rpl_corruption.result b/mysql-test/suite/binlog_encryption/rpl_corruption.result
index 25a82fd60cd..db72bb304fc 100644
--- a/mysql-test/suite/binlog_encryption/rpl_corruption.result
+++ b/mysql-test/suite/binlog_encryption/rpl_corruption.result
@@ -13,6 +13,7 @@ connection master;
 CREATE TABLE t1 (a INT NOT NULL PRIMARY KEY, b VARCHAR(10), c VARCHAR(100));
 include/stop_slave.inc
 # 2. Corruption in master binlog and SHOW BINLOG EVENTS
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug="+d,corrupt_read_log_event_char";
 SHOW BINLOG EVENTS;
 ERROR HY000: Error when executing command SHOW BINLOG EVENTS: Wrong offset or I/O error
@@ -55,9 +56,9 @@ connection slave;
 include/diff_tables.inc [master:test.t1, slave:test.t1]
 # 8. Clean up
 connection master;
-SET GLOBAL debug_dbug= "";
+set @@global.debug_dbug = @saved_dbug;
 SET GLOBAL master_verify_checksum = @old_master_verify_checksum;
 DROP TABLE t1;
 connection slave;
-SET GLOBAL debug_dbug= "";
+set @@global.debug_dbug = @saved_dbug;
 include/rpl_end.inc
diff --git a/mysql-test/suite/binlog_encryption/rpl_incident.result b/mysql-test/suite/binlog_encryption/rpl_incident.result
index 8fb4aa907cc..6dbe4417c5a 100644
--- a/mysql-test/suite/binlog_encryption/rpl_incident.result
+++ b/mysql-test/suite/binlog_encryption/rpl_incident.result
@@ -14,6 +14,7 @@ a
 1
 2
 3
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug= '+d,incident_database_resync_on_replace,*';
 REPLACE INTO t1 VALUES (4);
 SELECT * FROM t1;
@@ -22,6 +23,7 @@ a
 2
 3
 4
+set @@global.debug_dbug = @saved_dbug;
 connection slave;
 call mtr.add_suppression("Slave SQL.*The incident LOST_EVENTS occurred on the master.* 1590");
 include/wait_for_slave_sql_error.inc [errno=1590]
diff --git a/mysql-test/suite/binlog_encryption/rpl_init_slave_errors.result b/mysql-test/suite/binlog_encryption/rpl_init_slave_errors.result
index 91742814b4c..fc23734c645 100644
--- a/mysql-test/suite/binlog_encryption/rpl_init_slave_errors.result
+++ b/mysql-test/suite/binlog_encryption/rpl_init_slave_errors.result
@@ -4,12 +4,13 @@ connection slave;
 stop slave;
 reset slave;
 connection slave;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug= "d,simulate_io_slave_error_on_init,simulate_sql_slave_error_on_init";
 start slave;
 include/wait_for_slave_sql_error.inc [errno=1593]
 Last_SQL_Error = 'Failed during slave thread initialization'
 call mtr.add_suppression("Failed during slave.* thread initialization");
-SET GLOBAL debug_dbug= "";
+set @@global.debug_dbug = @saved_dbug;
 connection slave;
 reset slave;
 SET GLOBAL init_slave= "garbage";
diff --git a/mysql-test/suite/galera/disabled.def b/mysql-test/suite/galera/disabled.def
index 437b5358792..22b3d081087 100644
--- a/mysql-test/suite/galera/disabled.def
+++ b/mysql-test/suite/galera/disabled.def
@@ -20,7 +20,6 @@ MW-328B : MDEV-21483 galera.MW-328A galera.MW-328B
 MW-329 : MDEV-19962 Galera test failure on MW-329
 MW-336 : MDEV-21409: Galera test failure on MW-336
 MW-360 : needs rewrite to be MariaDB gtid compatible
-MW-388: MDEV-19803 Long semaphore wait error on galera.MW-388	
 galera.galera_defaults : MDEV-21494 Galera test sporadic failure on galera.galera_defaults
 galera_account_management : MariaDB 10.0 does not support ALTER USER
 galera_as_master_gtid : Requires MySQL GTID
@@ -57,7 +56,7 @@ galera_sst_mariabackup_table_options: MDEV-19741 Galera test failure on galera.g
 galera_toi_ddl_nonconflicting : MDEV-21518 galera.galera_toi_ddl_nonconflicting
 galera_var_innodb_disallow_writes : MDEV-20928 galera.galera_var_innodb_disallow_writes
 galera_var_node_address : MDEV-20485 Galera test failure
-galera_var_notify_cmd : MDEV-20600 Galera test galera_var_notify_cmd causes hang
+galera_var_notify_cmd : MDEV-21488,MDEV-20600
 galera_var_reject_queries : assertion in inline_mysql_socket_send
 galera_var_retry_autocommit: MDEV-18181 Galera test failure on galera.galera_var_retry_autocommit
 galera_wan : MDEV-17259 Test failure on galera.galera_wan
diff --git a/mysql-test/suite/galera/r/MW-388.result b/mysql-test/suite/galera/r/MW-388.result
index ab78b989efe..b16addc542a 100644
--- a/mysql-test/suite/galera/r/MW-388.result
+++ b/mysql-test/suite/galera/r/MW-388.result
@@ -20,18 +20,16 @@ connection node_1a;
 SET SESSION DEBUG_SYNC = "now WAIT_FOR sync.wsrep_apply_cb_reached";
 connection node_1;
 SET SESSION wsrep_sync_wait = 0;
-SET SESSION DEBUG_SYNC = 'wsrep_after_certification SIGNAL wsrep_after_certification_reached WAIT_FOR wsrep_after_certification_continue';
 CALL insert_proc ();;
 connection node_1a;
-SET SESSION DEBUG_SYNC = "now WAIT_FOR wsrep_after_certification_reached";
+SET SESSION wsrep_sync_wait = 0;
 SET GLOBAL DEBUG_DBUG = "";
-SET DEBUG_SYNC = "now SIGNAL wsrep_after_certification_continue";
 SET DEBUG_SYNC = "now SIGNAL signal.wsrep_apply_cb";
 connection node_2;
 connection node_1;
-SELECT @errno `expect 1213`;
-expect 1213
-1213
+SELECT @errno = 1213;
+@errno = 1213
+1
 SELECT * FROM t1;
 f1	f2
 1	node 2
diff --git a/mysql-test/suite/galera/r/galera_events2.result b/mysql-test/suite/galera/r/galera_events2.result
index 30a5d408bab..cd44579af90 100644
--- a/mysql-test/suite/galera/r/galera_events2.result
+++ b/mysql-test/suite/galera/r/galera_events2.result
@@ -16,6 +16,7 @@ SELECT EVENT_CATALOG, EVENT_SCHEMA, EVENT_NAME, DEFINER, EVENT_BODY, EVENT_DEFIN
 EVENT_CATALOG	EVENT_SCHEMA	EVENT_NAME	DEFINER	EVENT_BODY	EVENT_DEFINITION	EVENT_TYPE	EXECUTE_AT	INTERVAL_VALUE	INTERVAL_FIELD	STATUS	ON_COMPLETION	EVENT_COMMENT
 def	test	event_2	root@localhost	SQL	INSERT INTO event_table VALUES (1)	RECURRING	NULL	1	SECOND	ENABLED	NOT PRESERVE	
 connection node_2;
+set global wsrep_sync_wait=15;
 # node_2 event should be there
 SELECT EVENT_CATALOG, EVENT_SCHEMA, EVENT_NAME, DEFINER, EVENT_BODY, EVENT_DEFINITION, EVENT_TYPE, EXECUTE_AT, INTERVAL_VALUE, INTERVAL_FIELD, STATUS,ON_COMPLETION, EVENT_COMMENT FROM INFORMATION_SCHEMA.EVENTS WHERE EVENT_NAME='event_2';
 EVENT_CATALOG	EVENT_SCHEMA	EVENT_NAME	DEFINER	EVENT_BODY	EVENT_DEFINITION	EVENT_TYPE	EXECUTE_AT	INTERVAL_VALUE	INTERVAL_FIELD	STATUS	ON_COMPLETION	EVENT_COMMENT
diff --git a/mysql-test/suite/galera/t/MW-388.test b/mysql-test/suite/galera/t/MW-388.test
index e99559400c1..09fc8a8bfc9 100644
--- a/mysql-test/suite/galera/t/MW-388.test
+++ b/mysql-test/suite/galera/t/MW-388.test
@@ -1,5 +1,6 @@
 --source include/galera_cluster.inc
 --source include/have_debug_sync.inc
+
 --connection node_1
 CREATE TABLE t1 (f1 INTEGER PRIMARY KEY, f2 CHAR(255)) Engine=InnoDB;
 
@@ -30,6 +31,8 @@ DELIMITER ;|
 SET GLOBAL wsrep_slave_threads = 2;
 SET GLOBAL DEBUG_DBUG = "d,sync.wsrep_apply_cb";
 
+--let $expected_cert_failures = `SELECT VARIABLE_VALUE + 1 FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME = 'wsrep_local_cert_failures'`
+
 --connection node_2
 --send INSERT INTO t1 VALUES (1, 'node 2');
 
@@ -39,25 +42,24 @@ SET SESSION DEBUG_SYNC = "now WAIT_FOR sync.wsrep_apply_cb_reached";
 
 --connection node_1
 SET SESSION wsrep_sync_wait = 0;
-SET SESSION DEBUG_SYNC = 'wsrep_after_certification SIGNAL wsrep_after_certification_reached WAIT_FOR wsrep_after_certification_continue';
 --send CALL insert_proc ();
 
 --connection node_1a
-SET SESSION DEBUG_SYNC = "now WAIT_FOR wsrep_after_certification_reached";
+SET SESSION wsrep_sync_wait = 0;
+--let $wait_condition = SELECT VARIABLE_VALUE = $expected_cert_failures FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME = 'wsrep_local_cert_failures'
+--source include/wait_condition.inc
 
 
 SET GLOBAL DEBUG_DBUG = "";
-SET DEBUG_SYNC = "now SIGNAL wsrep_after_certification_continue";
 SET DEBUG_SYNC = "now SIGNAL signal.wsrep_apply_cb";
 
 --connection node_2
 --reap
 
 --connection node_1
-# We expect no errors here, because the handler in insert_proc()
-# caught the deadlock error
+# We expect no errors here, because the handler in insert_proc() caught the deadlock error
 --reap
-SELECT @errno `expect 1213`;
+SELECT @errno = 1213;
 SELECT * FROM t1;
 
 --connection node_2
diff --git a/mysql-test/suite/galera/t/galera_events2.test b/mysql-test/suite/galera/t/galera_events2.test
index 54b90386851..3dfbe406fc4 100644
--- a/mysql-test/suite/galera/t/galera_events2.test
+++ b/mysql-test/suite/galera/t/galera_events2.test
@@ -23,6 +23,7 @@ DO
 SELECT EVENT_CATALOG, EVENT_SCHEMA, EVENT_NAME, DEFINER, EVENT_BODY, EVENT_DEFINITION, EVENT_TYPE, EXECUTE_AT, INTERVAL_VALUE, INTERVAL_FIELD, STATUS,ON_COMPLETION, EVENT_COMMENT FROM INFORMATION_SCHEMA.EVENTS WHERE EVENT_NAME='event_2';
 
 --connection node_2
+set global wsrep_sync_wait=15;
 --echo # node_2 event should be there
 SELECT EVENT_CATALOG, EVENT_SCHEMA, EVENT_NAME, DEFINER, EVENT_BODY, EVENT_DEFINITION, EVENT_TYPE, EXECUTE_AT, INTERVAL_VALUE, INTERVAL_FIELD, STATUS,ON_COMPLETION, EVENT_COMMENT FROM INFORMATION_SCHEMA.EVENTS WHERE EVENT_NAME='event_2';
 
@@ -66,6 +67,9 @@ ALTER EVENT one_event ON SCHEDULE EVERY 10 SECOND;
 SELECT EVENT_CATALOG, EVENT_SCHEMA, EVENT_NAME, DEFINER, EVENT_BODY, EVENT_DEFINITION, EVENT_TYPE, EXECUTE_AT, INTERVAL_VALUE, INTERVAL_FIELD, STATUS,ON_COMPLETION, EVENT_COMMENT FROM INFORMATION_SCHEMA.EVENTS WHERE EVENT_NAME='one_event';
 
 --connection node_2
+--let $wait_condition = SELECT COUNT(*) = 1 FROM INFORMATION_SCHEMA.EVENTS WHERE EVENT_NAME='one_event';
+--source include/wait_condition.inc
+
 use events_test;
 --echo "The definer should be ev_test@localhost"
 SELECT EVENT_CATALOG, EVENT_SCHEMA, EVENT_NAME, DEFINER, EVENT_BODY, EVENT_DEFINITION, EVENT_TYPE, EXECUTE_AT, INTERVAL_VALUE, INTERVAL_FIELD, STATUS,ON_COMPLETION, EVENT_COMMENT FROM INFORMATION_SCHEMA.EVENTS WHERE EVENT_NAME='one_event';
diff --git a/mysql-test/suite/gcol/r/innodb_virtual_debug_purge.result b/mysql-test/suite/gcol/r/innodb_virtual_debug_purge.result
index d99565b2f4c..837f72129ca 100644
--- a/mysql-test/suite/gcol/r/innodb_virtual_debug_purge.result
+++ b/mysql-test/suite/gcol/r/innodb_virtual_debug_purge.result
@@ -208,7 +208,7 @@ DROP TABLE t1, t2;
 # MDEV-16222 Assertion `0' failed in row_purge_remove_sec_if_poss_leaf
 # on table with virtual columns and indexes
 #
-set @saved_dbug= @@global.debug_dbug;
+SET @saved_dbug= @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,ib_purge_virtual_mdev_16222_1,ib_purge_virtual_mdev_16222_2";
 create table t1 (
 pk serial, vb tinyblob as (b) virtual, b tinyblob,
@@ -253,7 +253,7 @@ SET GLOBAL innodb_debug_sync = "ib_clust_v_col_before_row_allocated "
 SET GLOBAL innodb_debug_sync = "ib_open_after_dict_open "
                                "SIGNAL purge_open "
                                "WAIT_FOR select_open";
-set @saved_dbug= @@global.debug_dbug;
+SET @saved_dbug= @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,ib_purge_virtual_index_callback";
 connect purge_waiter,localhost,root;
 SET debug_sync= "now WAIT_FOR before_row_allocated";
diff --git a/mysql-test/suite/gcol/t/innodb_virtual_debug_purge.test b/mysql-test/suite/gcol/t/innodb_virtual_debug_purge.test
index 276407007da..ca9d016fdcc 100644
--- a/mysql-test/suite/gcol/t/innodb_virtual_debug_purge.test
+++ b/mysql-test/suite/gcol/t/innodb_virtual_debug_purge.test
@@ -265,7 +265,7 @@ DROP TABLE t1, t2;
 --echo #
 
 --let $datadir= `select @@datadir`
-set @saved_dbug= @@global.debug_dbug;
+SET @saved_dbug= @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,ib_purge_virtual_mdev_16222_1,ib_purge_virtual_mdev_16222_2";
 
 create table t1 (
@@ -336,7 +336,7 @@ SET GLOBAL innodb_debug_sync = "ib_open_after_dict_open "
 
 # In 10.2 trx_undo_roll_ptr_is_insert(t_roll_ptr) condition never pass in purge,
 # so this condition is forced to pass in row_vers_old_has_index_entry
-set @saved_dbug= @@global.debug_dbug;
+SET @saved_dbug= @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,ib_purge_virtual_index_callback";
 
 # The purge starts from REPLACE command. To avoid possible race, separate
diff --git a/mysql-test/suite/innodb/disabled.def b/mysql-test/suite/innodb/disabled.def
index 35c941f8af7..3c2d32765d8 100644
--- a/mysql-test/suite/innodb/disabled.def
+++ b/mysql-test/suite/innodb/disabled.def
@@ -11,3 +11,4 @@
 ##############################################################################
 
 create-index-debug : MDEV-13680 InnoDB may crash when btr_page_alloc() fails
+innodb_wl6326 : MDEV-21535 Too broad ha_innobase::records_in_range()
diff --git a/mysql-test/suite/innodb/r/blob-update-debug.result b/mysql-test/suite/innodb/r/blob-update-debug.result
index 1360745b7e6..813a469dd2b 100644
--- a/mysql-test/suite/innodb/r/blob-update-debug.result
+++ b/mysql-test/suite/innodb/r/blob-update-debug.result
@@ -7,9 +7,11 @@ insert into t1 values (1, repeat('*', 50000));
 select f1, substring(f2, 1, 40) from t1;
 f1	substring(f2, 1, 40)
 1	****************************************
-set debug_dbug = 'd,row_ins_index_entry_timeout';
+set @saved_debug = @@session.debug_dbug;
+SET debug_dbug = 'd,row_ins_index_entry_timeout';
 update t1 set f1 = 3;
 select f1, substring(f2, 1, 40) from t1;
 f1	substring(f2, 1, 40)
 3	****************************************
 drop table t1;
+SET debug_dbug= @saved_debug;
diff --git a/mysql-test/suite/innodb/r/innodb-replace-debug.result b/mysql-test/suite/innodb/r/innodb-replace-debug.result
index 989fb055cbc..03e22b774e4 100644
--- a/mysql-test/suite/innodb/r/innodb-replace-debug.result
+++ b/mysql-test/suite/innodb/r/innodb-replace-debug.result
@@ -5,10 +5,10 @@ create table t1 (f1 int primary key, f2 int, f3 int, unique key k1(f2),
 key k2(f3)) engine=innodb;
 insert into t1 values (14, 24, 34);
 set @old_dbug= @@session.debug_dbug;
-set debug_dbug = '+d,row_ins_sec_index_entry_timeout';
+SET debug_dbug = '+d,row_ins_sec_index_entry_timeout';
 replace into t1 values (14, 25, 34);
 select * from t1;
 f1	f2	f3
 14	25	34
 drop table t1;
-set debug_dbug = @old_dbug;
+SET debug_dbug = @old_dbug;
diff --git a/mysql-test/suite/innodb/r/innodb-stats-initialize-failure.result b/mysql-test/suite/innodb/r/innodb-stats-initialize-failure.result
index ef2d3182b92..06bb708b82c 100644
--- a/mysql-test/suite/innodb/r/innodb-stats-initialize-failure.result
+++ b/mysql-test/suite/innodb/r/innodb-stats-initialize-failure.result
@@ -1,4 +1,5 @@
 call mtr.add_suppression("InnoDB: Warning: Index.*");
+SET @saved_dbug = @@SESSION.debug_dbug;
 set DEBUG_DBUG='+d,ib_ha_innodb_stat_not_initialized';
 create table t1(a int not null primary key, b int, c int, key(b), key(c)) engine=innodb;
 create procedure innodb_insert_proc (repeat_count int)
@@ -27,6 +28,6 @@ count(1)
 select count(1) from t1 where c between 7 and 787;
 count(1)
 781
-set DEBUG_DBUG=NULL;
 drop procedure innodb_insert_proc;
 drop table t1;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/innodb/r/innodb-wl5522-1.result b/mysql-test/suite/innodb/r/innodb-wl5522-1.result
index b2a5f49a9ad..55557a8fb99 100644
--- a/mysql-test/suite/innodb/r/innodb-wl5522-1.result
+++ b/mysql-test/suite/innodb/r/innodb-wl5522-1.result
@@ -389,7 +389,7 @@ CREATE TABLE testdb_wl5522.t1 ( i bigint) ENGINE = Innodb;
 ALTER TABLE testdb_wl5522.t1 DISCARD TABLESPACE;
 restore: t1 .ibd and .cfg files
 ALTER TABLE testdb_wl5522.t1 IMPORT TABLESPACE;
-ERROR HY000: Schema mismatch (Column i precise type mismatch.)
+ERROR HY000: Schema mismatch (Column i precise type mismatch, it's 0X408 in the table and 0X403 in the tablespace meta file)
 unlink: t1.ibd
 unlink: t1.cfg
 DROP TABLE testdb_wl5522.t1;
diff --git a/mysql-test/suite/innodb/r/innodb-wl5522.result b/mysql-test/suite/innodb/r/innodb-wl5522.result
index 50330b5b164..b83bfe39c21 100644
--- a/mysql-test/suite/innodb/r/innodb-wl5522.result
+++ b/mysql-test/suite/innodb/r/innodb-wl5522.result
@@ -429,7 +429,7 @@ SELECT * FROM t1;
 ERROR HY000: Tablespace has been discarded for table `t1`
 restore: t1 .ibd and .cfg files
 ALTER TABLE t1 IMPORT TABLESPACE;
-ERROR HY000: Schema mismatch (Column c2 precise type mismatch.)
+ERROR HY000: Schema mismatch (Column c2 precise type mismatch, it's 0X408 in the table and 0X403 in the tablespace meta file)
 unlink: t1.ibd
 unlink: t1.cfg
 DROP TABLE t1;
diff --git a/mysql-test/suite/innodb/r/innodb_bug11754376.result b/mysql-test/suite/innodb/r/innodb_bug11754376.result
index b9f2a169a73..650dfbb35c2 100644
--- a/mysql-test/suite/innodb/r/innodb_bug11754376.result
+++ b/mysql-test/suite/innodb/r/innodb_bug11754376.result
@@ -1,3 +1,5 @@
 CREATE TABLE bug11754376 (c INT) ENGINE=INNODB;
+SET @saved_dbug = @@SESSION.debug_dbug;
 SET SESSION DEBUG_DBUG='+d,test_normalize_table_name_low';
 DROP TABLE bug11754376;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/innodb/r/innodb_bug30113362.result b/mysql-test/suite/innodb/r/innodb_bug30113362.result
new file mode 100644
index 00000000000..6e7cafbecbb
--- /dev/null
+++ b/mysql-test/suite/innodb/r/innodb_bug30113362.result
@@ -0,0 +1,122 @@
+SET GLOBAL innodb_adaptive_hash_index = false;
+SET GLOBAL innodb_stats_persistent = false;
+connect  purge_control,localhost,root,,;
+START TRANSACTION WITH CONSISTENT SNAPSHOT;
+connect  con2,localhost,root,,;
+CREATE TABLE t1 (
+a00 CHAR(255) NOT NULL DEFAULT 'a',
+a01 CHAR(255) NOT NULL DEFAULT 'a',
+a02 CHAR(255) NOT NULL DEFAULT 'a',
+b INT NOT NULL DEFAULT 0,
+PRIMARY KEY(a00, a01, a02)
+) charset latin1 ENGINE = InnoDB COMMENT='MERGE_THRESHOLD=45';
+SET GLOBAL innodb_limit_optimistic_insert_debug = 3;
+CREATE PROCEDURE data_load_t1()
+BEGIN
+DECLARE c1 INT DEFAULT 97;
+DECLARE c2 INT DEFAULT 97;
+DECLARE c3 INT DEFAULT 97;
+WHILE c1 < 102 DO
+WHILE c2 < 123 DO
+WHILE c3 < 123 DO
+INSERT INTO t1 (a00) VALUES (CHAR(c1,c2,c3));
+SET c3 = c3 + 1;
+END WHILE;
+SET c3 = 97;
+SET c2 = c2 + 1;
+END WHILE;
+SET c2 = 97;
+SET c1 = c1 + 1;
+END WHILE;
+END |
+call data_load_t1();
+DROP PROCEDURE data_load_t1;
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+CLUST_INDEX_SIZE
+1856
+connection con2;
+DELETE FROM t1 WHERE a00 = 'cnm';
+COMMIT;
+BEGIN;
+INSERT INTO t1 SET a00 = 'cnm';
+connection purge_control;
+COMMIT;
+connection con2;
+SET GLOBAL innodb_limit_optimistic_insert_debug = 0;
+ROLLBACK;
+# Test start
+connection purge_control;
+START TRANSACTION WITH CONSISTENT SNAPSHOT;
+connection con2;
+DELETE FROM t1 WHERE a00 = 'bii';
+COMMIT;
+BEGIN;
+INSERT INTO t1 SET a00 = 'bii';
+SET DEBUG_SYNC = 'rollback_undo_pk SIGNAL roll1_wait WAIT_FOR roll2';
+SET DEBUG_SYNC = 'rollback_purge_clust SIGNAL rollback_waiting WAIT_FOR resume';
+ROLLBACK;
+connection purge_control;
+SET DEBUG_SYNC = 'now WAIT_FOR roll1_wait';
+COMMIT;
+SET DEBUG_SYNC = 'now SIGNAL roll2';
+connect  con1,localhost,root,,;
+SET DEBUG_SYNC = 'now WAIT_FOR rollback_waiting';
+SET DEBUG_SYNC = 'rw_s_lock_waiting SIGNAL lockwait1';
+SELECT a00 FROM t1 WHERE a00 = 'bii';
+connection default;
+SET DEBUG_SYNC = 'now WAIT_FOR lockwait1';
+SET DEBUG_SYNC = 'now SIGNAL resume';
+connection con1;
+a00
+connection con2;
+connection default;
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+CLUST_INDEX_SIZE
+1856
+DELETE FROM t1 WHERE a00 = 'dpn';
+COMMIT;
+INSERT INTO t1 SET a00 = 'dpn';
+ROLLBACK;
+ALTER TABLE t1 COMMENT='MERGE_THRESHOLD=35';
+connection purge_control;
+START TRANSACTION WITH CONSISTENT SNAPSHOT;
+connection con2;
+DELETE FROM t1 WHERE a00 = 'cnd';
+COMMIT;
+BEGIN;
+INSERT INTO t1 SET a00 = 'cnd';
+SET DEBUG_SYNC = 'rollback_undo_pk SIGNAL roll1_wait WAIT_FOR roll2';
+SET DEBUG_SYNC = 'rollback_purge_clust SIGNAL rollback_waiting WAIT_FOR resume EXECUTE 2';
+ROLLBACK;
+connection purge_control;
+SET DEBUG_SYNC = 'now WAIT_FOR roll1_wait';
+START TRANSACTION WITH CONSISTENT SNAPSHOT;
+SET DEBUG_SYNC = 'now SIGNAL roll2';
+connection con1;
+SET DEBUG_SYNC = 'now WAIT_FOR rollback_waiting TIMEOUT 1';
+SET DEBUG_SYNC = 'now SIGNAL resume';
+SET DEBUG_SYNC = 'now WAIT_FOR rollback_waiting TIMEOUT 1';
+disconnect purge_control;
+connection default;
+SET DEBUG_SYNC = 'now SIGNAL resume';
+disconnect con1;
+connection con2;
+disconnect con2;
+connection default;
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+CLUST_INDEX_SIZE
+1856
+SET DEBUG_SYNC = 'RESET';
+DROP TABLE t1;
diff --git a/mysql-test/suite/innodb/r/innodb_bug56947.result b/mysql-test/suite/innodb/r/innodb_bug56947.result
index 4248013b088..aa922776f7b 100644
--- a/mysql-test/suite/innodb/r/innodb_bug56947.result
+++ b/mysql-test/suite/innodb/r/innodb_bug56947.result
@@ -1,5 +1,6 @@
 SET GLOBAL innodb_file_per_table=0;
 create table bug56947(a int not null) engine = innodb;
+SET @saved_dbug = @@SESSION.debug_dbug;
 SET DEBUG_DBUG='+d,ib_rebuild_cannot_rename';
 alter table bug56947 add unique index (a);
 ERROR HY000: Got error 11 "xxx" from storage engine InnoDB
@@ -8,3 +9,4 @@ Table	Op	Msg_type	Msg_text
 test.bug56947	check	status	OK
 drop table bug56947;
 SET @@global.innodb_file_per_table=DEFAULT;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/innodb/r/innodb_corrupt_bit.result b/mysql-test/suite/innodb/r/innodb_corrupt_bit.result
index 2000db03efa..daf0345e8ca 100644
--- a/mysql-test/suite/innodb/r/innodb_corrupt_bit.result
+++ b/mysql-test/suite/innodb/r/innodb_corrupt_bit.result
@@ -24,7 +24,7 @@ test.corrupt_bit_test_�	check	Warning	InnoDB: Index idx is marked as corrupted
 test.corrupt_bit_test_�	check	Warning	InnoDB: Index idx� is marked as corrupted
 test.corrupt_bit_test_�	check	Warning	InnoDB: Index idxē is marked as corrupted
 test.corrupt_bit_test_�	check	error	Corrupt
-SET debug_dbug = @save_dbug;
+SET @@SESSION.debug_dbug = @save_dbug;
 CREATE INDEX idx3 ON corrupt_bit_test_�(b, c);
 ERROR HY000: Index idx is corrupted
 CREATE INDEX idx4 ON corrupt_bit_test_�(b, z);
diff --git a/mysql-test/suite/innodb/r/innodb_sys_semaphore_waits.result b/mysql-test/suite/innodb/r/innodb_sys_semaphore_waits.result
index 5f14ad9b0d7..65d0a0bde43 100644
--- a/mysql-test/suite/innodb/r/innodb_sys_semaphore_waits.result
+++ b/mysql-test/suite/innodb/r/innodb_sys_semaphore_waits.result
@@ -4,6 +4,7 @@ drop table if exists t1;
 connection con1;
 create table t1 (id integer, x integer) engine = InnoDB;
 insert into t1 values(0, 0);
+SET @saved_dbug = @@SESSION.debug_dbug;
 set DEBUG_DBUG='+d,fatal-semaphore-timeout';
 set autocommit=0;
 # Sending query on con1,
@@ -21,6 +22,6 @@ connection default;
 # Waitting for reconnect after mysqld restarts
 # Reconnected after mysqld was successfully restarted
 # Cleaning up before exit
-set DEBUG_DBUG=NULL;
+SET debug_dbug = @saved_dbug;
 drop table if exists t1;
 # Clean exit
diff --git a/mysql-test/suite/innodb/r/innodb_wl6326.result b/mysql-test/suite/innodb/r/innodb_wl6326.result
new file mode 100644
index 00000000000..6f7ad8a3de4
--- /dev/null
+++ b/mysql-test/suite/innodb/r/innodb_wl6326.result
@@ -0,0 +1,387 @@
+SET GLOBAL innodb_adaptive_hash_index = false;
+SET GLOBAL innodb_stats_persistent = false;
+connect  con1,localhost,root,,;
+connect  con2,localhost,root,,;
+connect  con3,localhost,root,,;
+CREATE TABLE t1 (
+a00 CHAR(255) NOT NULL DEFAULT 'a',
+a01 CHAR(255) NOT NULL DEFAULT 'a',
+a02 CHAR(255) NOT NULL DEFAULT 'a',
+a03 CHAR(255) NOT NULL DEFAULT 'a',
+a04 CHAR(255) NOT NULL DEFAULT 'a',
+a05 CHAR(255) NOT NULL DEFAULT 'a',
+a06 CHAR(255) NOT NULL DEFAULT 'a',
+b INT NOT NULL DEFAULT 0
+) ENGINE = InnoDB;
+ALTER TABLE t1 ADD PRIMARY KEY(
+a00,
+a01,
+a02,
+a03,
+a04,
+a05,
+a06
+);
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+CLUST_INDEX_SIZE
+1
+SET GLOBAL innodb_limit_optimistic_insert_debug = 7;
+INSERT INTO t1 (a00) VALUES ('aa');
+INSERT INTO t1 (a00) VALUES ('ab');
+INSERT INTO t1 (a00) VALUES ('ac');
+INSERT INTO t1 (a00) VALUES ('ad');
+INSERT INTO t1 (a00) VALUES ('ae');
+INSERT INTO t1 (a00) VALUES ('af');
+INSERT INTO t1 (a00) VALUES ('ag');
+INSERT INTO t1 (a00) VALUES ('ah');
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+CLUST_INDEX_SIZE
+3
+INSERT INTO t1 (a00) VALUES ('ai');
+INSERT INTO t1 (a00) VALUES ('aj');
+INSERT INTO t1 (a00) VALUES ('ak');
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+CLUST_INDEX_SIZE
+4
+INSERT INTO t1 (a00) VALUES ('al');
+INSERT INTO t1 (a00) VALUES ('am');
+INSERT INTO t1 (a00) VALUES ('an');
+INSERT INTO t1 (a00) VALUES ('ao');
+INSERT INTO t1 (a00) VALUES ('ap');
+INSERT INTO t1 (a00) VALUES ('aq');
+INSERT INTO t1 (a00) VALUES ('ar');
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+CLUST_INDEX_SIZE
+5
+INSERT INTO t1 (a00) VALUES ('as');
+INSERT INTO t1 (a00) VALUES ('at');
+INSERT INTO t1 (a00) VALUES ('au');
+INSERT INTO t1 (a00) VALUES ('av');
+INSERT INTO t1 (a00) VALUES ('aw');
+INSERT INTO t1 (a00) VALUES ('ax');
+INSERT INTO t1 (a00) VALUES ('ay');
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+CLUST_INDEX_SIZE
+6
+INSERT INTO t1 (a00) VALUES ('az');
+INSERT INTO t1 (a00) VALUES ('ba');
+INSERT INTO t1 (a00) VALUES ('bb');
+INSERT INTO t1 (a00) VALUES ('bc');
+INSERT INTO t1 (a00) VALUES ('bd');
+INSERT INTO t1 (a00) VALUES ('be');
+INSERT INTO t1 (a00) VALUES ('bf');
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+CLUST_INDEX_SIZE
+7
+INSERT INTO t1 (a00) VALUES ('bg');
+INSERT INTO t1 (a00) VALUES ('bh');
+INSERT INTO t1 (a00) VALUES ('bi');
+INSERT INTO t1 (a00) VALUES ('bj');
+INSERT INTO t1 (a00) VALUES ('bk');
+INSERT INTO t1 (a00) VALUES ('bl');
+INSERT INTO t1 (a00) VALUES ('bm');
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+CLUST_INDEX_SIZE
+8
+INSERT INTO t1 (a00) VALUES ('bn');
+INSERT INTO t1 (a00) VALUES ('bo');
+INSERT INTO t1 (a00) VALUES ('bp');
+INSERT INTO t1 (a00) VALUES ('bq');
+INSERT INTO t1 (a00) VALUES ('br');
+INSERT INTO t1 (a00) VALUES ('bs');
+INSERT INTO t1 (a00) VALUES ('bt');
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+CLUST_INDEX_SIZE
+11
+INSERT INTO t1 (a00) VALUES ('bu');
+INSERT INTO t1 (a00) VALUES ('bv');
+INSERT INTO t1 (a00) VALUES ('bw');
+INSERT INTO t1 (a00) VALUES ('bx');
+INSERT INTO t1 (a00) VALUES ('by');
+INSERT INTO t1 (a00) VALUES ('bz');
+INSERT INTO t1 (a00) VALUES ('ca');
+INSERT INTO t1 (a00) VALUES ('cb');
+INSERT INTO t1 (a00) VALUES ('cc');
+INSERT INTO t1 (a00) VALUES ('cd');
+INSERT INTO t1 (a00) VALUES ('ce');
+INSERT INTO t1 (a00) VALUES ('cf');
+INSERT INTO t1 (a00) VALUES ('cg');
+INSERT INTO t1 (a00) VALUES ('ch');
+INSERT INTO t1 (a00) VALUES ('ci');
+INSERT INTO t1 (a00) VALUES ('cj');
+INSERT INTO t1 (a00) VALUES ('ck');
+INSERT INTO t1 (a00) VALUES ('cl');
+INSERT INTO t1 (a00) VALUES ('cm');
+INSERT INTO t1 (a00) VALUES ('cn');
+INSERT INTO t1 (a00) VALUES ('co');
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+CLUST_INDEX_SIZE
+15
+INSERT INTO t1 (a00) VALUES ('cp');
+INSERT INTO t1 (a00) VALUES ('cq');
+INSERT INTO t1 (a00) VALUES ('cr');
+INSERT INTO t1 (a00) VALUES ('cs');
+INSERT INTO t1 (a00) VALUES ('ct');
+INSERT INTO t1 (a00) VALUES ('cu');
+INSERT INTO t1 (a00) VALUES ('cv');
+INSERT INTO t1 (a00) VALUES ('cw');
+INSERT INTO t1 (a00) VALUES ('cx');
+INSERT INTO t1 (a00) VALUES ('cy');
+INSERT INTO t1 (a00) VALUES ('cz');
+INSERT INTO t1 (a00) VALUES ('da');
+INSERT INTO t1 (a00) VALUES ('db');
+INSERT INTO t1 (a00) VALUES ('dc');
+INSERT INTO t1 (a00) VALUES ('dd');
+INSERT INTO t1 (a00) VALUES ('de');
+INSERT INTO t1 (a00) VALUES ('df');
+INSERT INTO t1 (a00) VALUES ('dg');
+INSERT INTO t1 (a00) VALUES ('dh');
+INSERT INTO t1 (a00) VALUES ('di');
+INSERT INTO t1 (a00) VALUES ('dj');
+INSERT INTO t1 (a00) VALUES ('dk');
+INSERT INTO t1 (a00) VALUES ('dl');
+INSERT INTO t1 (a00) VALUES ('dm');
+INSERT INTO t1 (a00) VALUES ('dn');
+INSERT INTO t1 (a00) VALUES ('do');
+INSERT INTO t1 (a00) VALUES ('dp');
+INSERT INTO t1 (a00) VALUES ('dq');
+INSERT INTO t1 (a00) VALUES ('dr');
+INSERT INTO t1 (a00) VALUES ('ds');
+INSERT INTO t1 (a00) VALUES ('dt');
+INSERT INTO t1 (a00) VALUES ('du');
+INSERT INTO t1 (a00) VALUES ('dv');
+INSERT INTO t1 (a00) VALUES ('dw');
+INSERT INTO t1 (a00) VALUES ('dx');
+INSERT INTO t1 (a00) VALUES ('dy');
+INSERT INTO t1 (a00) VALUES ('dz');
+INSERT INTO t1 (a00) VALUES ('ea');
+INSERT INTO t1 (a00) VALUES ('eb');
+INSERT INTO t1 (a00) VALUES ('ec');
+INSERT INTO t1 (a00) VALUES ('ed');
+INSERT INTO t1 (a00) VALUES ('ee');
+INSERT INTO t1 (a00) VALUES ('ef');
+INSERT INTO t1 (a00) VALUES ('eg');
+INSERT INTO t1 (a00) VALUES ('eh');
+INSERT INTO t1 (a00) VALUES ('ei');
+INSERT INTO t1 (a00) VALUES ('ej');
+INSERT INTO t1 (a00) VALUES ('ek');
+INSERT INTO t1 (a00) VALUES ('el');
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+CLUST_INDEX_SIZE
+23
+INSERT INTO t1 (a00) VALUES ('em');
+INSERT INTO t1 (a00) VALUES ('en');
+INSERT INTO t1 (a00) VALUES ('eo');
+INSERT INTO t1 (a00) VALUES ('ep');
+INSERT INTO t1 (a00) VALUES ('eq');
+INSERT INTO t1 (a00) VALUES ('er');
+INSERT INTO t1 (a00) VALUES ('es');
+INSERT INTO t1 (a00) VALUES ('et');
+INSERT INTO t1 (a00) VALUES ('eu');
+INSERT INTO t1 (a00) VALUES ('ev');
+INSERT INTO t1 (a00) VALUES ('ew');
+INSERT INTO t1 (a00) VALUES ('ex');
+INSERT INTO t1 (a00) VALUES ('ey');
+INSERT INTO t1 (a00) VALUES ('ez');
+INSERT INTO t1 (a00) VALUES ('fa');
+INSERT INTO t1 (a00) VALUES ('fb');
+INSERT INTO t1 (a00) VALUES ('fc');
+INSERT INTO t1 (a00) VALUES ('fd');
+INSERT INTO t1 (a00) VALUES ('fe');
+INSERT INTO t1 (a00) VALUES ('ff');
+INSERT INTO t1 (a00) VALUES ('fg');
+INSERT INTO t1 (a00) VALUES ('fh');
+INSERT INTO t1 (a00) VALUES ('fi');
+INSERT INTO t1 (a00) VALUES ('fj');
+INSERT INTO t1 (a00) VALUES ('fk');
+INSERT INTO t1 (a00) VALUES ('fl');
+INSERT INTO t1 (a00) VALUES ('fm');
+INSERT INTO t1 (a00) VALUES ('fn');
+INSERT INTO t1 (a00) VALUES ('fo');
+INSERT INTO t1 (a00) VALUES ('fp');
+INSERT INTO t1 (a00) VALUES ('fq');
+INSERT INTO t1 (a00) VALUES ('fr');
+INSERT INTO t1 (a00) VALUES ('fs');
+INSERT INTO t1 (a00) VALUES ('ft');
+INSERT INTO t1 (a00) VALUES ('fu');
+INSERT INTO t1 (a00) VALUES ('fv');
+INSERT INTO t1 (a00) VALUES ('fw');
+INSERT INTO t1 (a00) VALUES ('fx');
+INSERT INTO t1 (a00) VALUES ('fy');
+INSERT INTO t1 (a00) VALUES ('fz');
+INSERT INTO t1 (a00) VALUES ('ga');
+INSERT INTO t1 (a00) VALUES ('gb');
+INSERT INTO t1 (a00) VALUES ('gc');
+INSERT INTO t1 (a00) VALUES ('gd');
+INSERT INTO t1 (a00) VALUES ('ge');
+INSERT INTO t1 (a00) VALUES ('gf');
+INSERT INTO t1 (a00) VALUES ('gg');
+INSERT INTO t1 (a00) VALUES ('gh');
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+CLUST_INDEX_SIZE
+29
+SET GLOBAL innodb_limit_optimistic_insert_debug = 0;
+# Test start
+SET DEBUG_SYNC = 'RESET';
+INSERT INTO t1 (a00) VALUES ('bfa');
+connection con1;
+SET DEBUG_SYNC = 'before_insert_pessimitic_row_ins_clust SIGNAL reached WAIT_FOR continue';
+INSERT INTO t1 (a00) VALUES ('bfb');
+connection con2;
+SET DEBUG_SYNC = 'now WAIT_FOR reached';
+SELECT a00,a01 FROM t1 WHERE a00 = 'aa';
+a00	a01
+aa	a
+SELECT a00,a01 FROM t1 WHERE a00 = 'aq';
+a00	a01
+aq	a
+SELECT a00,a01 FROM t1 WHERE a00 = 'cp';
+a00	a01
+cp	a
+SELECT a00,a01 FROM t1 WHERE a00 = 'el';
+a00	a01
+el	a
+SET DEBUG_SYNC = 'rw_s_lock_waiting SIGNAL lockwait1';
+SELECT a00,a01 FROM t1 WHERE a00 = 'ar';
+connection con3;
+SET DEBUG_SYNC = 'rw_s_lock_waiting SIGNAL lockwait2';
+SELECT a00,a01 FROM t1 WHERE a00 = 'cn';
+connection default;
+SET DEBUG_SYNC = 'now WAIT_FOR lockwait1 TIMEOUT 1';
+SET DEBUG_SYNC = 'now WAIT_FOR lockwait2 TIMEOUT 1';
+SET DEBUG_SYNC = 'now SIGNAL continue';
+connection con1;
+Warnings:
+Warning	1639	debug sync point wait timed out
+connection con2;
+a00	a01
+ar	a
+connection con3;
+a00	a01
+cn	a
+connection default;
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+CLUST_INDEX_SIZE
+30
+SET DEBUG_SYNC = 'RESET';
+INSERT INTO t1 (a00) VALUES ('coa');
+connection con1;
+SET DEBUG_SYNC = 'before_insert_pessimitic_row_ins_clust SIGNAL reached WAIT_FOR continue';
+INSERT INTO t1 (a00) VALUES ('cob');
+connection con2;
+SET DEBUG_SYNC = 'now WAIT_FOR reached';
+SET DEBUG_SYNC = 'rw_s_lock_waiting SIGNAL lockwait1';
+SELECT a00,a01 FROM t1 WHERE a00 = 'aa';
+connection con3;
+SET DEBUG_SYNC = 'rw_s_lock_waiting SIGNAL lockwait2';
+SELECT a00,a01 FROM t1 WHERE a00 = 'el';
+connection default;
+SET DEBUG_SYNC = 'now WAIT_FOR lockwait1 TIMEOUT 1';
+SET DEBUG_SYNC = 'now WAIT_FOR lockwait2 TIMEOUT 1';
+SET DEBUG_SYNC = 'now SIGNAL continue';
+connection con1;
+connection con2;
+a00	a01
+aa	a
+connection con3;
+a00	a01
+el	a
+connection default;
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+CLUST_INDEX_SIZE
+31
+SET DEBUG_SYNC = 'RESET';
+INSERT INTO t1 (a00) VALUES ('gba');
+connection con1;
+SET DEBUG_SYNC = 'before_insert_pessimitic_row_ins_clust SIGNAL reached WAIT_FOR continue';
+INSERT INTO t1 (a00) VALUES ('gbb');
+connection con2;
+SET DEBUG_SYNC = 'now WAIT_FOR reached';
+SELECT a00,a01 FROM t1 WHERE a00 = 'aa';
+a00	a01
+aa	a
+SELECT a00,a01 FROM t1 WHERE a00 = 'ek';
+a00	a01
+ek	a
+SET DEBUG_SYNC = 'rw_s_lock_waiting SIGNAL lockwait1';
+SELECT a00,a01 FROM t1 WHERE a00 = 'el';
+connection con3;
+SET DEBUG_SYNC = 'rw_s_lock_waiting SIGNAL lockwait2';
+SELECT a00,a01 FROM t1 WHERE a00 = 'gb';
+connection default;
+SET DEBUG_SYNC = 'now WAIT_FOR lockwait1 TIMEOUT 1';
+SET DEBUG_SYNC = 'now WAIT_FOR lockwait2 TIMEOUT 1';
+SET DEBUG_SYNC = 'now SIGNAL continue';
+connection con1;
+connection con2;
+a00	a01
+el	a
+connection con3;
+a00	a01
+gb	a
+connection default;
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+CLUST_INDEX_SIZE
+32
+SET DEBUG_SYNC = 'RESET';
+connection default;
+disconnect con1;
+disconnect con2;
+disconnect con3;
+DROP TABLE t1;
diff --git a/mysql-test/suite/innodb/r/innodb_wl6326_big.result b/mysql-test/suite/innodb/r/innodb_wl6326_big.result
new file mode 100644
index 00000000000..3ff6d0d0b5c
--- /dev/null
+++ b/mysql-test/suite/innodb/r/innodb_wl6326_big.result
@@ -0,0 +1,449 @@
+CREATE SCHEMA my_schema;
+USE my_schema;
+CREATE FUNCTION f_thread_id (i INT) RETURNS CHAR(4) DETERMINISTIC
+RETURN CONCAT(LPAD(CAST(i AS CHAR),3,'_'),'_') ;
+SELECT CONCAT('->', f_thread_id( 1), '<-');
+CONCAT('->', f_thread_id( 1), '<-')
+->__1_<-
+SELECT CONCAT('->', f_thread_id(12), '<-');
+CONCAT('->', f_thread_id(12), '<-')
+->_12_<-
+SET @extra_int    = 1;
+SET @extra_string = f_thread_id(@extra_int);
+SELECT @extra_int , @extra_string;
+@extra_int	@extra_string
+1	__1_
+CREATE FUNCTION f_col_int1 (i INT) RETURNS INT(20) DETERMINISTIC
+RETURN i * 1000 + @extra_int ;
+SELECT f_col_int1(my_col) AS my_result
+FROM (SELECT 1 AS my_col UNION SELECT 12 UNION SELECT 123
+UNION SELECT 1234 UNION SELECT 12345) AS tx;
+my_result
+1001
+12001
+123001
+1234001
+12345001
+CREATE FUNCTION f_col_int2 (i INT) RETURNS INT(20) DETERMINISTIC
+RETURN @extra_int * 10000000 + i ;
+SELECT f_col_int2(my_col) AS my_result
+FROM (SELECT 1 AS my_col UNION SELECT 12 UNION SELECT 123
+UNION SELECT 1234 UNION SELECT 12345) AS tx;
+my_result
+10000001
+10000012
+10000123
+10001234
+10012345
+CREATE FUNCTION f_col_int3 (i INT) RETURNS INT(20) DETERMINISTIC
+RETURN @extra_int ;
+SELECT f_col_int3(my_col) AS my_result
+FROM (SELECT 1 AS my_col UNION SELECT 12 UNION SELECT 123
+UNION SELECT 1234 UNION SELECT 12345) AS tx;
+my_result
+1
+1
+1
+1
+1
+CREATE FUNCTION f_col_blob (i INT) RETURNS BLOB DETERMINISTIC
+RETURN RPAD(@extra_string,(@@innodb_page_size / 2 ) + 1,'a');
+SELECT CONCAT('->', SUBSTR(f_col_blob(my_col) FROM 1 FOR 10),
+'<-.....->', SUBSTR(f_col_blob(my_col) FROM -10 FOR 10), '<-') AS my_result
+FROM (SELECT 1 AS my_col UNION SELECT 12 UNION SELECT 123
+UNION SELECT 1234 UNION SELECT 12345) AS tx;
+my_result
+->__1_aaaaaa<-.....->aaaaaaaaaa<-
+->__1_aaaaaa<-.....->aaaaaaaaaa<-
+->__1_aaaaaa<-.....->aaaaaaaaaa<-
+->__1_aaaaaa<-.....->aaaaaaaaaa<-
+->__1_aaaaaa<-.....->aaaaaaaaaa<-
+CREATE FUNCTION f_col_char0 (i INT) RETURNS CHAR(255) DETERMINISTIC
+RETURN LPAD(CAST(i AS CHAR),255,' ');
+SELECT CONCAT('->', f_col_char0(my_col), '<-') AS my_result
+FROM (SELECT 1 AS my_col UNION SELECT 12 UNION SELECT 123
+UNION SELECT 1234 UNION SELECT 12345) AS tx;
+my_result
+->                                                                                                                                                                                                                                                              1<-
+->                                                                                                                                                                                                                                                             12<-
+->                                                                                                                                                                                                                                                            123<-
+->                                                                                                                                                                                                                                                           1234<-
+->                                                                                                                                                                                                                                                          12345<-
+CREATE FUNCTION f_col_char1 (i INT) RETURNS CHAR(26) DETERMINISTIC
+RETURN
+CONCAT('B',
+LPAD(SUBSTR(CAST(i AS CHAR),1,(LENGTH(CAST(i AS CHAR)) DIV 2)),10,' '),
+@extra_string,
+RPAD(SUBSTR(CAST(i AS CHAR), -((LENGTH(CAST(i AS CHAR)) + 1) DIV 2)),10,' '),
+'E') ;
+SELECT CONCAT('->', f_col_char1(my_col), '<-') AS my_result
+FROM (SELECT 1 AS my_col UNION SELECT 12 UNION SELECT 123
+UNION SELECT 1234 UNION SELECT 12345) AS tx;
+my_result
+->B          __1_1         E<-
+->B         1__1_2         E<-
+->B         1__1_23        E<-
+->B        12__1_34        E<-
+->B        12__1_345       E<-
+CREATE FUNCTION f_col_char2 (i INT) RETURNS CHAR(26) DETERMINISTIC
+RETURN
+CONCAT('B',
+RPAD(SUBSTR(CAST(i AS CHAR),1,(LENGTH(CAST(i AS CHAR)) DIV 2)),10,' '),
+@extra_string,
+LPAD(SUBSTR(CAST(i AS CHAR), -((LENGTH(CAST(i AS CHAR)) + 1) DIV 2)),10,' '),
+'E');
+SELECT CONCAT('->', f_col_char2(my_col), '<-') AS my_result
+FROM (SELECT 1 AS my_col UNION SELECT 12 UNION SELECT 123
+UNION SELECT 1234 UNION SELECT 12345) AS tx;
+my_result
+->B          __1_         1E<-
+->B1         __1_         2E<-
+->B1         __1_        23E<-
+->B12        __1_        34E<-
+->B12        __1_       345E<-
+CREATE FUNCTION f_col_char3 (i INT) RETURNS CHAR(26) DETERMINISTIC
+RETURN
+CONCAT('B',@extra_string,LPAD(CAST(i AS CHAR),20,' '),'E');
+SELECT CONCAT('->', f_col_char3(my_col), '<-') AS my_result
+FROM (SELECT 1 AS my_col UNION SELECT 12 UNION SELECT 123
+UNION SELECT 1234 UNION SELECT 12345) AS tx;
+my_result
+->B__1_                   1E<-
+->B__1_                  12E<-
+->B__1_                 123E<-
+->B__1_                1234E<-
+->B__1_               12345E<-
+CREATE FUNCTION f_col_char4 (i INT) RETURNS CHAR(26) DETERMINISTIC
+RETURN
+CONCAT('B',RPAD(CAST(i AS CHAR),20,' '),@extra_string,'E');
+SELECT CONCAT('->', f_col_char4(my_col), '<-') AS my_result
+FROM (SELECT 1 AS my_col UNION SELECT 12 UNION SELECT 123
+UNION SELECT 1234 UNION SELECT 12345) AS tx;
+my_result
+->B1                   __1_E<-
+->B12                  __1_E<-
+->B123                 __1_E<-
+->B1234                __1_E<-
+->B12345               __1_E<-
+CREATE TABLE my_metrics LIKE information_schema.innodb_metrics;
+ALTER TABLE my_metrics ADD COLUMN phase ENUM('after', 'before'),
+DROP COLUMN SUBSYSTEM, DROP COLUMN TYPE, DROP COLUMN COMMENT,
+ADD PRIMARY KEY (NAME,phase);
+CREATE TABLE t1 (
+col_int0 BIGINT,
+col_int1 BIGINT,
+col_int2 BIGINT,
+col_int3 BIGINT,
+col_blob BLOB,
+col_char0 VARCHAR(255),
+col_char1 VARCHAR(30),
+col_char2 VARCHAR(30),
+col_char3 VARCHAR(30),
+col_char4 VARCHAR(30)
+) ENGINE = InnoDB;
+ALTER TABLE t1 ADD UNIQUE KEY uidx_col_int0 (col_int0),
+ADD UNIQUE KEY uidx1 (col_int1, col_char0),
+ADD UNIQUE KEY uidx2 (col_int2, col_char0, col_int1),
+ADD UNIQUE KEY uidx3 (col_int3, col_int2, col_char0),
+ADD UNIQUE KEY uidx4 (col_char1, col_char0),
+ADD UNIQUE KEY uidx5 (col_char2, col_char0, col_char1),
+ADD UNIQUE KEY uidx6 (col_char3, col_char2, col_char0),
+ADD UNIQUE KEY uidx7 (col_int1, col_int2, col_int3, col_char4,
+col_char1, col_char2, col_char3, col_char0),
+ADD KEY idx8 (col_blob(10), col_char4);
+CREATE PROCEDURE proc_fill_t1 (max_row_count INT, load_unit INT)
+BEGIN
+DECLARE my_count INTEGER DEFAULT 0;
+DECLARE max_load_count INTEGER DEFAULT 0;
+DROP TABLE IF EXISTS t0;
+CREATE TEMPORARY TABLE t0 (col_int0 BIGINT, PRIMARY KEY(col_int0));
+WHILE (my_count < load_unit ) DO
+SET my_count = my_count + 1;
+INSERT INTO t0 SET col_int0 = my_count;
+END WHILE;
+SET max_load_count = (SELECT (max_row_count DIV load_unit) + 1 );
+SELECT COUNT(col_int0) INTO @val FROM t1;
+SET my_count = 0;
+REPEAT
+INSERT INTO t1 (col_int0, col_int1, col_int2, col_int3, col_blob,
+col_char0, col_char1, col_char2,col_char3,col_char4)
+SELECT col_int0 + @val,
+f_col_int1(col_int0 + @val),
+f_col_int2(col_int0 + @val),
+f_col_int3(col_int0 + @val),
+f_col_blob(col_int0 + @val),
+f_col_char0(col_int0 + @val),
+f_col_char1(col_int0 + @val),
+f_col_char2(col_int0 + @val),
+f_col_char3(col_int0 + @val),
+f_col_char4(col_int0 + @val)
+FROM t0;
+COMMIT;
+SELECT MAX(col_int0) INTO @val FROM t1;
+SET my_count = my_count + 1;
+UNTIL( my_count > max_load_count OR @val >= max_row_count )
+END REPEAT;
+DROP TEMPORARY TABLE t0;
+END|
+CREATE PROCEDURE proc_dml (max_duration INT, t1_stripe_half INT)
+BEGIN
+DECLARE aux INTEGER DEFAULT 0;
+DECLARE start_time INT;
+DECLARE CONTINUE HANDLER FOR SQLEXCEPTION, SQLWARNING, NOT FOUND BEGIN END;
+SET @extra_int    = CONNECTION_ID();
+SET @extra_string = f_thread_id(@extra_int);
+SELECT ROUND(MAX(col_int0) / 2 ) INTO @t1_half FROM t1;
+# The user lock 'Blocker' should be already set by some other session S1.
+# S1 starts the race by releasing that lock.
+# Wait till the lock is released and the lock can be obtained.
+# In order to prevent endless waiting in case of non foreseen problems
+# limit the timespan to 30 seconds.
+SELECT GET_LOCK('Blocker', 30) INTO @aux;
+# Release the lock immediate so that the other "runner" sessions start too.
+SELECT RELEASE_LOCK('Blocker') INTO @aux;
+SET start_time = UNIX_TIMESTAMP();
+WHILE (UNIX_TIMESTAMP() - start_time < max_duration) DO
+SET @aux = @t1_half - t1_stripe_half + ROUND(RAND() * t1_stripe_half * 2);
+UPDATE t1 SET
+col_int1  = f_col_int1(col_int0),
+col_int2  = f_col_int2(col_int0),
+col_int3  = f_col_int3(col_int0),
+col_blob  = f_col_blob(col_int0),
+col_char0 = f_col_char0(col_int0),
+col_char1 = f_col_char1(col_int0),
+col_char2 = f_col_char2(col_int0),
+col_char3 = f_col_char3(col_int0),
+col_char4 = f_col_char4(col_int0)
+WHERE col_int0 = @aux;
+COMMIT;
+END WHILE;
+END|
+SET GLOBAL innodb_monitor_disable = "innodb_rwlock_sx_%";
+SET @pre_reset_ts = NOW();
+SET GLOBAL innodb_monitor_reset   = "innodb_rwlock_sx_%";
+SET @pre_enable_ts = NOW();
+SET GLOBAL innodb_monitor_enable  = "innodb_rwlock_sx_%";
+SET @pre_collect_ts = NOW();
+DELETE FROM my_metrics;
+INSERT INTO my_metrics
+SELECT NAME, COUNT, MAX_COUNT, MIN_COUNT, AVG_COUNT,
+COUNT_RESET, MAX_COUNT_RESET, MIN_COUNT_RESET, AVG_COUNT_RESET,
+TIME_ENABLED, TIME_DISABLED, TIME_ELAPSED, TIME_RESET,
+STATUS, 'before'
+FROM information_schema.innodb_metrics
+WHERE NAME LIKE 'innodb_rwlock_sx_%';
+# TC-01 There are exact three entries "innodb_rwlock_sx_%" with the
+#       with the name which follow in innodb_metrics.
+#    pass
+SELECT COUNT(*) INTO @sx_count FROM my_metrics;
+# TC-02 Counting is now enabled. ALL = @sx_count entries show that.
+#    pass
+# TC-03 @pre_reset_ts < TIME_RESET. ALL = @sx_count entries show that.
+#    pass
+# TC-04 @pre_enable_ts < TIME_ENABLED. ALL = @sx_count entries show that.
+#    pass
+# TC-05 TIME_RESET < TIME_ENABLED AND TIME_ENABLED < @pre_collect_ts
+#       AND TIME_ELAPSED > 0. ALL = @sx_count entries show that.
+#    pass
+# TC-06 COUNT_RESET = MAX_COUNT_RESET. ALL = @sx_count entries show that.
+#    pass
+SET GLOBAL innodb_monitor_reset = "innodb_rwlock_sx_%";
+SHOW ENGINE INNODB STATUS;
+DELETE FROM my_metrics;
+INSERT INTO my_metrics
+SELECT NAME, COUNT, MAX_COUNT, MIN_COUNT, AVG_COUNT,
+COUNT_RESET, MAX_COUNT_RESET, MIN_COUNT_RESET, AVG_COUNT_RESET,
+TIME_ENABLED, TIME_DISABLED, TIME_ELAPSED, TIME_RESET,
+STATUS, 'before'
+FROM information_schema.innodb_metrics
+WHERE NAME LIKE 'innodb_rwlock_sx_%';
+SET @extra_string = '__0_';
+SET @extra_int    =    0;
+# TC-07 One session inserts some significant amount of rows into t1.
+#       The system MUST survive that.
+SET @max_row_count = <max_row_count>;
+SET @load_unit = <load_unit>;
+SET @start_time = UNIX_TIMESTAMP();
+SET AUTOCOMMIT = OFF;
+CALL proc_fill_t1 (@max_row_count, @load_unit);
+#    pass
+SET AUTOCOMMIT = ON;
+SELECT col_int0 INTO @t1_half FROM t1
+WHERE col_int0 >= (@val DIV 2) ORDER BY col_int0 LIMIT 1;
+SHOW ENGINE INNODB STATUS;
+SELECT col_int0, col_int1, col_int2, col_int3,
+CONCAT('->', SUBSTR(col_blob FROM 1 FOR 10),
+'<-.....->', SUBSTR(col_blob FROM -10 FOR 10), '<-') AS  col_blobx,
+CONCAT('->',col_char0,'<-') AS col_char0x,
+CONCAT('->',col_char1,'<-') AS col_char1x,
+CONCAT('->',col_char2,'<-') AS col_char2x,
+CONCAT('->',col_char3,'<-') AS col_char3x,
+CONCAT('->',col_char4,'<-') AS col_char4x
+FROM t1 WHERE col_int0 between 98 AND 102;
+col_int0	98
+col_int1	98000
+col_int2	98
+col_int3	0
+col_blobx	->__0_aaaaaa<-.....->aaaaaaaaaa<-
+col_char0x	->                                                                                                                                                                                                                                                             98<-
+col_char1x	->B         9__0_8         E<-
+col_char2x	->B9         __0_         8E<-
+col_char3x	->B__0_                  98E<-
+col_char4x	->B98                  __0_E<-
+col_int0	99
+col_int1	99000
+col_int2	99
+col_int3	0
+col_blobx	->__0_aaaaaa<-.....->aaaaaaaaaa<-
+col_char0x	->                                                                                                                                                                                                                                                             99<-
+col_char1x	->B         9__0_9         E<-
+col_char2x	->B9         __0_         9E<-
+col_char3x	->B__0_                  99E<-
+col_char4x	->B99                  __0_E<-
+col_int0	100
+col_int1	100000
+col_int2	100
+col_int3	0
+col_blobx	->__0_aaaaaa<-.....->aaaaaaaaaa<-
+col_char0x	->                                                                                                                                                                                                                                                            100<-
+col_char1x	->B         1__0_00        E<-
+col_char2x	->B1         __0_        00E<-
+col_char3x	->B__0_                 100E<-
+col_char4x	->B100                 __0_E<-
+col_int0	101
+col_int1	101000
+col_int2	101
+col_int3	0
+col_blobx	->__0_aaaaaa<-.....->aaaaaaaaaa<-
+col_char0x	->                                                                                                                                                                                                                                                            101<-
+col_char1x	->B         1__0_01        E<-
+col_char2x	->B1         __0_        01E<-
+col_char3x	->B__0_                 101E<-
+col_char4x	->B101                 __0_E<-
+col_int0	102
+col_int1	102000
+col_int2	102
+col_int3	0
+col_blobx	->__0_aaaaaa<-.....->aaaaaaaaaa<-
+col_char0x	->                                                                                                                                                                                                                                                            102<-
+col_char1x	->B         1__0_02        E<-
+col_char2x	->B1         __0_        02E<-
+col_char3x	->B__0_                 102E<-
+col_char4x	->B102                 __0_E<-
+# TC-11 Several concurrent sessions perform updates in t1 like mad.
+#       The system MUST survive this.
+#       Printing of statements is partially suppressed.
+SET @start_time = UNIX_TIMESTAMP();
+SELECT 1 FROM t1 WHERE col_int0 = @t1_half FOR UPDATE;
+1
+1
+SELECT GET_LOCK('Blocker', 1000) ;
+GET_LOCK('Blocker', 1000)
+1
+RELEASE_LOCK('Blocker')
+1
+#    pass
+SHOW ENGINE INNODB STATUS;
+# TC-13 One session performs ALTER TABLE t1 ADD KEY ... on the fat table t1.
+#       The system MUST survive this.
+SET @start_time = UNIX_TIMESTAMP();
+ALTER TABLE t1 ADD KEY idx_col_char4_col_char0 (col_char4,col_char0);
+SHOW ENGINE INNODB STATUS;
+#    pass
+# TC-15 One session performs a fat update on the fat table t1.
+#       The system MUST survive this.
+SET @start_time   = UNIX_TIMESTAMP();
+SET @extra_int    = 13;
+SET @extra_string = f_thread_id(@extra_int);
+UPDATE t1 SET
+col_int1  = f_col_int1(col_int0),  col_int2  = f_col_int2(col_int0),
+col_int3  = f_col_int3(col_int0),  col_blob  = f_col_blob(col_int0),
+col_char0 = f_col_char0(col_int0), col_char1 = f_col_char1(col_int0),
+col_char2 = f_col_char2(col_int0), col_char3 = f_col_char3(col_int0),
+col_char4 = f_col_char4(col_int0)
+WHERE col_int0 BETWEEN @t1_half - 2500 AND @t1_half + 2500;
+COMMIT;
+SHOW ENGINE INNODB STATUS;
+#    pass
+INSERT INTO my_metrics
+SELECT NAME, COUNT, MAX_COUNT, MIN_COUNT, AVG_COUNT,
+COUNT_RESET, MAX_COUNT_RESET, MIN_COUNT_RESET, AVG_COUNT_RESET,
+TIME_ENABLED, TIME_DISABLED, TIME_ELAPSED, TIME_RESET,
+STATUS, 'after'
+FROM information_schema.innodb_metrics
+WHERE NAME LIKE 'innodb_rwlock_sx_%';
+# TC-16 The following activities happend after reset in innodb_metrics
+#       - Insert some significant amount of rows into t1.
+#       - Several concurrent users perform excessive updates in t1.
+#       - ALTER TABLE ... ADD KEY <sufficient big enough structure>
+#       - One UPDATE statement modifying a huge slice of t1.
+#       Any of them causes heavy use of SX lock and therefore COUNT_RESET
+#       must have grown for ALL = @sx_count entries.
+#    pass
+# TC-09 Heavy activity after reset.
+#       COUNT_RESET = MAX_COUNT_RESET for ALL = @sx_count entries
+#       needs to stay valid though he counters will have grown.
+#    pass
+DELETE FROM my_metrics;
+INSERT INTO my_metrics
+SELECT NAME, COUNT, MAX_COUNT, MIN_COUNT, AVG_COUNT,
+COUNT_RESET, MAX_COUNT_RESET, MIN_COUNT_RESET, AVG_COUNT_RESET,
+TIME_ENABLED, TIME_DISABLED, TIME_ELAPSED, TIME_RESET,
+STATUS, 'before'
+FROM information_schema.innodb_metrics
+WHERE NAME LIKE 'innodb_rwlock_sx_%';
+SET GLOBAL innodb_monitor_reset = "innodb_rwlock_sx_%";
+INSERT INTO my_metrics
+SELECT NAME, COUNT, MAX_COUNT, MIN_COUNT, AVG_COUNT,
+COUNT_RESET, MAX_COUNT_RESET, MIN_COUNT_RESET, AVG_COUNT_RESET,
+TIME_ENABLED, TIME_DISABLED, TIME_ELAPSED, TIME_RESET,
+STATUS, 'after'
+FROM information_schema.innodb_metrics
+WHERE NAME LIKE 'innodb_rwlock_sx_%';
+# TC-08 There was a reset. COUNT_RESET = MAX_COUNT_RESET for ALL
+#       = @sx_count entries.
+#    pass
+# TC-17 We had heavy activity causing big counters and after that a reset.
+#       Reset causes COUNT > COUNT_RESET AND MAX_COUNT > MAX_COUNT_RESET
+#       for ALL @sx_count entries.
+#    pass
+# TC-18 We had some reset but this must not decrease COUNT or MAX_COUNT
+#       after.COUNT >= before.COUNT AND
+#       after.MAX_COUNT >= before.MAX_COUNT for ALL @sx_count entries.
+#    pass
+# TC-19 We had some reset after heavy activity and this must cause
+#       after.COUNT_RESET < before.COUNT_RESET
+#       AND after.MAX_COUNT_RESET < before.MAX_COUNT_RESET AND
+#       for ALL @sx_count entries.
+#    pass
+connection con10;
+disconnect con10;
+connection con9;
+disconnect con9;
+connection con8;
+disconnect con8;
+connection con7;
+disconnect con7;
+connection con6;
+disconnect con6;
+connection con5;
+disconnect con5;
+connection con4;
+disconnect con4;
+connection con3;
+disconnect con3;
+connection con2;
+disconnect con2;
+connection con1;
+disconnect con1;
+connection default;
+USE test;
+DROP SCHEMA my_schema;
+SET GLOBAL innodb_monitor_disable   = all;
+SET GLOBAL innodb_monitor_reset_all = all;
+SET GLOBAL innodb_monitor_enable    = default;
+SET GLOBAL innodb_monitor_disable   = default;
+SET GLOBAL innodb_monitor_reset     = default;
+SET GLOBAL innodb_monitor_reset_all = default;
+SET GLOBAL innodb_monitor_disable   = "innodb_rwlock_sx_%";
+SET GLOBAL innodb_monitor_reset     = "innodb_rwlock_sx_%";
diff --git a/mysql-test/suite/innodb/r/redo_log_during_checkpoint.result b/mysql-test/suite/innodb/r/redo_log_during_checkpoint.result
index efe48682a6f..3915b07f12e 100644
--- a/mysql-test/suite/innodb/r/redo_log_during_checkpoint.result
+++ b/mysql-test/suite/innodb/r/redo_log_during_checkpoint.result
@@ -4,8 +4,8 @@ SET GLOBAL innodb_master_thread_disabled_debug = 1;
 SET GLOBAL innodb_log_checkpoint_now = 1;
 CREATE DATABASE very_long_database_name;
 USE very_long_database_name;
-set debug_dbug = '+d,increase_mtr_checkpoint_size';
-set debug_dbug = '+d,crash_after_checkpoint';
+SET debug_dbug = '+d,increase_mtr_checkpoint_size';
+SET debug_dbug = '+d,crash_after_checkpoint';
 set global innodb_log_checkpoint_now = 1;
 ERROR HY000: Lost connection to MySQL server during query
 # Skip MLOG_FILE_NAME redo records during recovery
@@ -18,7 +18,7 @@ SET GLOBAL innodb_log_checkpoint_now = 1;
 # exceeds LOG_CHECKPOINT_FREE_PER_THREAD size during checkpoint.
 CREATE DATABASE very_long_database_name;
 USE very_long_database_name;
-set debug_dbug = '+d,crash_after_checkpoint';
+SET debug_dbug = '+d,crash_after_checkpoint';
 set global innodb_log_checkpoint_now = 1;
 ERROR HY000: Lost connection to MySQL server during query
 # Skip MLOG_FILE_NAME redo records during recovery
diff --git a/mysql-test/suite/innodb/t/blob-update-debug.test b/mysql-test/suite/innodb/t/blob-update-debug.test
index 948cd749148..8d35dbfc70e 100644
--- a/mysql-test/suite/innodb/t/blob-update-debug.test
+++ b/mysql-test/suite/innodb/t/blob-update-debug.test
@@ -11,7 +11,9 @@
 create table t1 (f1 int primary key, f2 blob) engine = innodb;
 insert into t1 values (1, repeat('*', 50000));
 select f1, substring(f2, 1, 40) from t1;
-set debug_dbug = 'd,row_ins_index_entry_timeout';
+set @saved_debug = @@session.debug_dbug;
+SET debug_dbug = 'd,row_ins_index_entry_timeout';
 update t1 set f1 = 3;
 select f1, substring(f2, 1, 40) from t1;
 drop table t1;
+SET debug_dbug= @saved_debug;
diff --git a/mysql-test/suite/innodb/t/innodb-replace-debug.test b/mysql-test/suite/innodb/t/innodb-replace-debug.test
index 7e710ae154c..823712a01f1 100644
--- a/mysql-test/suite/innodb/t/innodb-replace-debug.test
+++ b/mysql-test/suite/innodb/t/innodb-replace-debug.test
@@ -9,8 +9,8 @@ create table t1 (f1 int primary key, f2 int, f3 int, unique key k1(f2),
   key k2(f3)) engine=innodb;
 insert into t1 values (14, 24, 34);
 set @old_dbug= @@session.debug_dbug;
-set debug_dbug = '+d,row_ins_sec_index_entry_timeout';
+SET debug_dbug = '+d,row_ins_sec_index_entry_timeout';
 replace into t1 values (14, 25, 34);
 select * from t1;
 drop table t1;
-set debug_dbug = @old_dbug;
+SET debug_dbug = @old_dbug;
diff --git a/mysql-test/suite/innodb/t/innodb-stats-initialize-failure.test b/mysql-test/suite/innodb/t/innodb-stats-initialize-failure.test
index e480f0caf07..d5d04190b8a 100644
--- a/mysql-test/suite/innodb/t/innodb-stats-initialize-failure.test
+++ b/mysql-test/suite/innodb/t/innodb-stats-initialize-failure.test
@@ -6,6 +6,7 @@
 
 call mtr.add_suppression("InnoDB: Warning: Index.*");
 # This caused crash earlier
+SET @saved_dbug = @@SESSION.debug_dbug;
 set DEBUG_DBUG='+d,ib_ha_innodb_stat_not_initialized';
 create table t1(a int not null primary key, b int, c int, key(b), key(c)) engine=innodb;
 
@@ -32,8 +33,8 @@ select count(1) from t1 where a between 5 and 100;
 select count(1) from t1 where b between 5 and 256;
 select count(1) from t1 where c between 7 and 787;
 
-set DEBUG_DBUG=NULL;
+
 
 drop procedure innodb_insert_proc;
 drop table t1;
-
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/innodb/t/innodb_bug11754376.test b/mysql-test/suite/innodb/t/innodb_bug11754376.test
index a7f35c1a960..64547d409b3 100644
--- a/mysql-test/suite/innodb/t/innodb_bug11754376.test
+++ b/mysql-test/suite/innodb/t/innodb_bug11754376.test
@@ -8,7 +8,8 @@
 CREATE TABLE bug11754376 (c INT) ENGINE=INNODB;
 
 # This will invoke test_normalize_table_name_low() in debug builds
-
+SET @saved_dbug = @@SESSION.debug_dbug;
 SET SESSION DEBUG_DBUG='+d,test_normalize_table_name_low';
 
 DROP TABLE bug11754376;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/innodb/t/innodb_bug30113362.opt b/mysql-test/suite/innodb/t/innodb_bug30113362.opt
new file mode 100644
index 00000000000..99bf0e5a28b
--- /dev/null
+++ b/mysql-test/suite/innodb/t/innodb_bug30113362.opt
@@ -0,0 +1 @@
+--innodb-sys-tablestats
diff --git a/mysql-test/suite/innodb/t/innodb_bug30113362.test b/mysql-test/suite/innodb/t/innodb_bug30113362.test
new file mode 100644
index 00000000000..6d8833a38fc
--- /dev/null
+++ b/mysql-test/suite/innodb/t/innodb_bug30113362.test
@@ -0,0 +1,236 @@
+#
+# Test for Bug#30113362 : BTR_CUR_WILL_MODIFY_TREE() IS INSUFFICIENT FOR HIGHER TREE LEVEL
+#
+
+--source include/have_innodb.inc
+--source include/have_debug.inc
+--source include/have_debug_sync.inc
+--source include/have_innodb_16k.inc
+
+--disable_query_log
+SET @old_innodb_limit_optimistic_insert_debug = @@innodb_limit_optimistic_insert_debug;
+SET @old_innodb_adaptive_hash_index = @@innodb_adaptive_hash_index;
+SET @old_innodb_stats_persistent = @@innodb_stats_persistent;
+--enable_query_log
+
+# Save the initial number of concurrent sessions
+--source include/count_sessions.inc
+
+SET GLOBAL innodb_adaptive_hash_index = false;
+SET GLOBAL innodb_stats_persistent = false;
+
+connect (purge_control,localhost,root,,);
+START TRANSACTION WITH CONSISTENT SNAPSHOT;
+
+--connect (con2,localhost,root,,)
+
+CREATE TABLE t1 (
+  a00 CHAR(255) NOT NULL DEFAULT 'a',
+  a01 CHAR(255) NOT NULL DEFAULT 'a',
+  a02 CHAR(255) NOT NULL DEFAULT 'a',
+  b INT NOT NULL DEFAULT 0,
+  PRIMARY KEY(a00, a01, a02)
+) charset latin1 ENGINE = InnoDB COMMENT='MERGE_THRESHOLD=45';
+
+#
+# Prepare primary key index tree to be used for this test.
+#
+
+SET GLOBAL innodb_limit_optimistic_insert_debug = 3;
+
+delimiter |;
+CREATE PROCEDURE data_load_t1()
+BEGIN
+  DECLARE c1 INT DEFAULT 97;
+  DECLARE c2 INT DEFAULT 97;
+  DECLARE c3 INT DEFAULT 97;
+
+  WHILE c1 < 102 DO
+    WHILE c2 < 123 DO
+      WHILE c3 < 123 DO
+        INSERT INTO t1 (a00) VALUES (CHAR(c1,c2,c3));
+        SET c3 = c3 + 1;
+      END WHILE;
+      SET c3 = 97;
+      SET c2 = c2 + 1;
+    END WHILE;
+    SET c2 = 97;
+    SET c1 = c1 + 1;
+  END WHILE;
+END |
+delimiter ;|
+call data_load_t1();
+DROP PROCEDURE data_load_t1;
+
+# all node pages are sparse (max 3 node_ptrs)
+ANALYZE TABLE t1;
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+connection con2;
+DELETE FROM t1 WHERE a00 = 'cnm';
+COMMIT;
+BEGIN;
+INSERT INTO t1 SET a00 = 'cnm';
+# causes "domino falling" merges to upper level
+connection purge_control;
+COMMIT;
+connection con2;
+SET GLOBAL innodb_limit_optimistic_insert_debug = 0;
+ROLLBACK;
+
+# at this moment, in the tree,
+# ...
+# level 4: ...(ast,avw,ayz)(bcc,bff,bii,bll,boo,brr,buu,bxx,cba,ced,cqp,cts)(cwv,czy,ddb)...
+# ...
+
+--echo # Test start
+
+# (1) Similar case to the first reported corefile at bug#30113362
+#     - Deleting 'bii' causes "domino falling" merges and the node_ptr becomes left_most of level 4.
+#       So, the operation needs upper level pages' X-latch, though doesn't cause merge more.
+
+connection purge_control;
+START TRANSACTION WITH CONSISTENT SNAPSHOT;
+connection con2;
+DELETE FROM t1 WHERE a00 = 'bii';
+COMMIT;
+BEGIN;
+INSERT INTO t1 SET a00 = 'bii';
+SET DEBUG_SYNC = 'rollback_undo_pk SIGNAL roll1_wait WAIT_FOR roll2';
+SET DEBUG_SYNC = 'rollback_purge_clust SIGNAL rollback_waiting WAIT_FOR resume';
+send ROLLBACK;
+
+connection purge_control;
+SET DEBUG_SYNC = 'now WAIT_FOR roll1_wait';
+COMMIT;
+SET DEBUG_SYNC = 'now SIGNAL roll2';
+
+connect (con1,localhost,root,,);
+SET DEBUG_SYNC = 'now WAIT_FOR rollback_waiting';
+SET DEBUG_SYNC = 'rw_s_lock_waiting SIGNAL lockwait1';
+send SELECT a00 FROM t1 WHERE a00 = 'bii';
+
+connection default;
+SET DEBUG_SYNC = 'now WAIT_FOR lockwait1';
+# bug#30113362 caused deadlock
+SET DEBUG_SYNC = 'now SIGNAL resume';
+
+connection con1;
+reap;
+connection con2;
+reap;
+connection default;
+
+ANALYZE TABLE t1;
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+# (2) Confirm blocking domain caused by DELETE modify_tree for tall index tree
+
+# at this moment, in the tree,
+# ...
+# level 4: ...(ajk,amn,apq)(ast,avw,ayz,bll,boo,brr,buu,bxx,cba,ced,cqp,cts)(cwv,czy,ddb)(dge,djh,dmk)(dpn,dsq,dvt)(dyw,ebz,efc)...
+# ...
+
+# makes >17 records in level4 [(2^(4-1))*2 + 1]. (causes never left_most records)
+DELETE FROM t1 WHERE a00 = 'dpn';
+COMMIT;
+INSERT INTO t1 SET a00 = 'dpn';
+ROLLBACK;
+
+# at this moment, in the tree,
+# (* before "]" and after "[" records are treated as left_most possible records)
+# ...
+# level 4: ...(ajk,amn,apq)(ast,avw,ayz,bll,boo,brr,buu,bxx],cba,ced,[cqp,cts,cwv,czy,ddb,dge,dsq,dvt)(dyw,ebz,efc)...
+# level 3: ...(cba,ccb,cdc)(ced,cfe,cgf,chg],cih,cji,[ckj,clk,con,cpo)(cqp,crq,csr)...
+# level 2: ...(ckj,cks,clb)(clk,clt],cmc,cml,cmu,cnd,[cnv,coe)(con,cow,cpf)...
+# level 1: ...(cmu,cmx,cna)(cnd],cng,cnj,cnp,[cns)(cnv,cny,cob)...
+# level 0: ...(cnd,cne,cnf)(cng,cnh,cni)(cnj,cnk,cnl,cnn,cno)(cnp,cnq,cnr)...
+
+# deletes just 'ced' node_ptr only from level 4. doesn't cause merge and never left_most.
+# adjusts MERGE_THRESHOLD to do so.
+ALTER TABLE t1 COMMENT='MERGE_THRESHOLD=35';
+
+connection purge_control;
+START TRANSACTION WITH CONSISTENT SNAPSHOT;
+
+connection con2;
+DELETE FROM t1 WHERE a00 = 'cnd';
+COMMIT;
+BEGIN;
+INSERT INTO t1 SET a00 = 'cnd';
+SET DEBUG_SYNC = 'rollback_undo_pk SIGNAL roll1_wait WAIT_FOR roll2';
+SET DEBUG_SYNC = 'rollback_purge_clust SIGNAL rollback_waiting WAIT_FOR resume EXECUTE 2';
+send ROLLBACK;
+
+connection purge_control;
+SET DEBUG_SYNC = 'now WAIT_FOR roll1_wait';
+START TRANSACTION WITH CONSISTENT SNAPSHOT;
+SET DEBUG_SYNC = 'now SIGNAL roll2';
+
+connection con1;
+# FIXME: For some reason, we will not always receive these signals!
+--disable_warnings
+# An optimistic row_undo_mod_remove_clust_low() will fail.
+SET DEBUG_SYNC = 'now WAIT_FOR rollback_waiting TIMEOUT 1';
+SET DEBUG_SYNC = 'now SIGNAL resume';
+# Wait for the pessimistic row_undo_mod_remove_clust_low() attempt.
+SET DEBUG_SYNC = 'now WAIT_FOR rollback_waiting TIMEOUT 1';
+--enable_warnings
+disconnect purge_control;
+
+# The expectation should be...
+# level 0: (#cnd#,cne,cnf): causes merge
+# level 1: (#cnd#],cng,cnj,cnp,[cns): left_most
+# level 2: (clk,clt],cmc,cml,cmu,#cnd#,[cnv,coe): causes merge
+# level 3: (ced,cfe,cgf,chg],cih,cji,[ckj,#clk#,con,cpo): left_most possible (not cause merge)
+# level 4: (ast,avw,ayz,bll,boo,brr,buu,bxx],cba,#ced#,[cqp,cts,cwv,czy,ddb,dge,dsq,dvt): no merge, not left_most possible
+# So, the top X-latch page is at level4. (ast~dvt)
+
+# blocking domain based on whether its ancestor is latched or not.
+# (*[]: ancestor is X-latched)
+# level 0: ...(asq,asr,ass) [(ast,asu,asv)...(dyt,dyu,dyv)] (dyw,dyx,dyy)...
+
+# Not blocked searches
+## In MariaDB, both these will block, because we use different DEBUG_SYNC
+## instrumentation (in rollback, not purge) and the root page (number 3)
+## is being latched in row_undo_mod_remove_clust_low().
+## SELECT a00 FROM t1 WHERE a00 = 'ass';
+## SELECT a00 FROM t1 WHERE a00 = 'dyx';
+
+## SET DEBUG_SYNC = 'rw_s_lock_waiting SIGNAL lockwait1';
+## send SELECT a00 FROM t1 WHERE a00 = 'ast';
+
+## connection con2;
+## SET DEBUG_SYNC = 'rw_s_lock_waiting SIGNAL lockwait2';
+## send SELECT a00 FROM t1 WHERE a00 = 'dyw';
+
+connection default;
+## SET DEBUG_SYNC = 'now WAIT_FOR lockwait1';
+## SET DEBUG_SYNC = 'now WAIT_FOR lockwait2';
+SET DEBUG_SYNC = 'now SIGNAL resume';
+
+## connection con1;
+## reap;
+disconnect con1;
+
+connection con2;
+reap;
+disconnect con2;
+
+connection default;
+ANALYZE TABLE t1;
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+
+# Cleanup
+SET DEBUG_SYNC = 'RESET';
+
+DROP TABLE t1;
+
+--disable_query_log
+SET GLOBAL innodb_limit_optimistic_insert_debug = @old_innodb_limit_optimistic_insert_debug;
+SET GLOBAL innodb_adaptive_hash_index = @old_innodb_adaptive_hash_index;
+SET GLOBAL innodb_stats_persistent = @old_innodb_stats_persistent;
+--enable_query_log
+
+--source include/wait_until_count_sessions.inc
diff --git a/mysql-test/suite/innodb/t/innodb_bug56947.test b/mysql-test/suite/innodb/t/innodb_bug56947.test
index 84c5e70e1b5..ce64f1a8322 100644
--- a/mysql-test/suite/innodb/t/innodb_bug56947.test
+++ b/mysql-test/suite/innodb/t/innodb_bug56947.test
@@ -7,6 +7,7 @@
 SET GLOBAL innodb_file_per_table=0;
 create table bug56947(a int not null) engine = innodb;
 
+SET @saved_dbug = @@SESSION.debug_dbug;
 SET DEBUG_DBUG='+d,ib_rebuild_cannot_rename';
 --replace_regex /"[^"]*"/"xxx"/
 --error ER_GET_ERRNO
@@ -15,3 +16,4 @@ check table bug56947;
 
 drop table bug56947;
 SET @@global.innodb_file_per_table=DEFAULT;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/innodb/t/innodb_corrupt_bit.test b/mysql-test/suite/innodb/t/innodb_corrupt_bit.test
index 1d723c0bbc3..f1fd7f3c56a 100644
--- a/mysql-test/suite/innodb/t/innodb_corrupt_bit.test
+++ b/mysql-test/suite/innodb/t/innodb_corrupt_bit.test
@@ -36,7 +36,7 @@ select count(*) from corrupt_bit_test_�;
 SET @save_dbug = @@SESSION.debug_dbug;
 SET debug_dbug = '+d,dict_set_index_corrupted';
 check table corrupt_bit_test_�;
-SET debug_dbug = @save_dbug;
+SET @@SESSION.debug_dbug = @save_dbug;
 
 # Cannot create new indexes while corrupted indexes exist
 --error ER_INDEX_CORRUPT
diff --git a/mysql-test/suite/innodb/t/innodb_sys_semaphore_waits.test b/mysql-test/suite/innodb/t/innodb_sys_semaphore_waits.test
index e7acb98b0d0..ccd9e3d70f4 100644
--- a/mysql-test/suite/innodb/t/innodb_sys_semaphore_waits.test
+++ b/mysql-test/suite/innodb/t/innodb_sys_semaphore_waits.test
@@ -17,6 +17,7 @@ eval create table t1 (id integer, x integer) engine = InnoDB;
 insert into t1 values(0, 0);
 
 # Enable the debug injection.
+SET @saved_dbug = @@SESSION.debug_dbug;
 set DEBUG_DBUG='+d,fatal-semaphore-timeout';
 set autocommit=0;
 
@@ -107,7 +108,7 @@ source include/wait_until_connected_again.inc;
 
 --echo # Cleaning up before exit
 --disable_warnings
-set DEBUG_DBUG=NULL;
+SET debug_dbug = @saved_dbug;
 drop table if exists t1;
 --enable_warnings
 
diff --git a/mysql-test/suite/innodb/t/innodb_wl6326.opt b/mysql-test/suite/innodb/t/innodb_wl6326.opt
new file mode 100644
index 00000000000..99bf0e5a28b
--- /dev/null
+++ b/mysql-test/suite/innodb/t/innodb_wl6326.opt
@@ -0,0 +1 @@
+--innodb-sys-tablestats
diff --git a/mysql-test/suite/innodb/t/innodb_wl6326.test b/mysql-test/suite/innodb/t/innodb_wl6326.test
new file mode 100644
index 00000000000..71eba94be04
--- /dev/null
+++ b/mysql-test/suite/innodb/t/innodb_wl6326.test
@@ -0,0 +1,506 @@
+#
+# WL#6326: InnoDB: fix index->lock contention
+#
+
+--source include/have_innodb.inc
+--source include/have_debug.inc
+--source include/have_debug_sync.inc
+--source include/have_innodb_16k.inc
+
+--disable_query_log
+SET @old_innodb_limit_optimistic_insert_debug = @@innodb_limit_optimistic_insert_debug;
+SET @old_innodb_adaptive_hash_index = @@innodb_adaptive_hash_index;
+SET @old_innodb_stats_persistent = @@innodb_stats_persistent;
+--enable_query_log
+
+# Save the initial number of concurrent sessions
+--source include/count_sessions.inc
+
+SET GLOBAL innodb_adaptive_hash_index = false;
+SET GLOBAL innodb_stats_persistent = false;
+
+--connect (con1,localhost,root,,)
+--connect (con2,localhost,root,,)
+--connect (con3,localhost,root,,)
+
+CREATE TABLE t1 (
+  a00 CHAR(255) NOT NULL DEFAULT 'a',
+  a01 CHAR(255) NOT NULL DEFAULT 'a',
+  a02 CHAR(255) NOT NULL DEFAULT 'a',
+  a03 CHAR(255) NOT NULL DEFAULT 'a',
+  a04 CHAR(255) NOT NULL DEFAULT 'a',
+  a05 CHAR(255) NOT NULL DEFAULT 'a',
+  a06 CHAR(255) NOT NULL DEFAULT 'a',
+  b INT NOT NULL DEFAULT 0
+) ENGINE = InnoDB;
+
+ALTER TABLE t1 ADD PRIMARY KEY(
+  a00,
+  a01,
+  a02,
+  a03,
+  a04,
+  a05,
+  a06
+);
+
+#
+# Prepare primary key index tree to be used for this test.
+#
+
+# Only root (1)
+ANALYZE TABLE t1;
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+# Make the first records sparse artificially,
+# not to cause modify_tree by single node_ptr insert operation.
+# * (7 - 2) records should be larger than a half of the page size
+# * (7 + 2) records should be fit to the page
+# (above t1 definition is already adjusted)
+SET GLOBAL innodb_limit_optimistic_insert_debug = 7;
+
+INSERT INTO t1 (a00) VALUES ('aa');
+INSERT INTO t1 (a00) VALUES ('ab');
+INSERT INTO t1 (a00) VALUES ('ac');
+INSERT INTO t1 (a00) VALUES ('ad');
+INSERT INTO t1 (a00) VALUES ('ae');
+INSERT INTO t1 (a00) VALUES ('af');
+INSERT INTO t1 (a00) VALUES ('ag');
+INSERT INTO t1 (a00) VALUES ('ah');
+# Raise root (1-2)
+# (aa,ad)
+# (aa,ab,ac)(ad,ae,af,ag,ah)
+ANALYZE TABLE t1;
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+INSERT INTO t1 (a00) VALUES ('ai');
+INSERT INTO t1 (a00) VALUES ('aj');
+INSERT INTO t1 (a00) VALUES ('ak');
+# Split leaf (1-3)
+# (aa,ad,ak)
+# (aa,ab,ac)(ad,ae,af,ag,ah,ai,aj)(ak)
+ANALYZE TABLE t1;
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+INSERT INTO t1 (a00) VALUES ('al');
+INSERT INTO t1 (a00) VALUES ('am');
+INSERT INTO t1 (a00) VALUES ('an');
+INSERT INTO t1 (a00) VALUES ('ao');
+INSERT INTO t1 (a00) VALUES ('ap');
+INSERT INTO t1 (a00) VALUES ('aq');
+INSERT INTO t1 (a00) VALUES ('ar');
+# Split leaf (1-4)
+# (aa,ad,ak,ar)
+# (aa,ab,ac)(ad,ae,af,ag,ah,ai,aj)(ak,al,am,an,ao,ap,aq)(ar)
+ANALYZE TABLE t1;
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+INSERT INTO t1 (a00) VALUES ('as');
+INSERT INTO t1 (a00) VALUES ('at');
+INSERT INTO t1 (a00) VALUES ('au');
+INSERT INTO t1 (a00) VALUES ('av');
+INSERT INTO t1 (a00) VALUES ('aw');
+INSERT INTO t1 (a00) VALUES ('ax');
+INSERT INTO t1 (a00) VALUES ('ay');
+# Split leaf (1-5)
+# (aa,ad,ak,ar,ay)
+# (aa,ab,ac)(ad,ae,af,ag,ah,ai,aj)(ak,al,am,an,ao,ap,aq)(ar,as,at,au,av,aw,ax)(ay)
+ANALYZE TABLE t1;
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+INSERT INTO t1 (a00) VALUES ('az');
+INSERT INTO t1 (a00) VALUES ('ba');
+INSERT INTO t1 (a00) VALUES ('bb');
+INSERT INTO t1 (a00) VALUES ('bc');
+INSERT INTO t1 (a00) VALUES ('bd');
+INSERT INTO t1 (a00) VALUES ('be');
+INSERT INTO t1 (a00) VALUES ('bf');
+# Split leaf (1-6)
+# (aa,ad,ak,ar,ay,bf)
+# (aa,ab,ac)(ad..)(ak..)(ar,as,at,au,av,aw,ax)(ay,az,ba,bb,bc,bd,be)(bf)
+ANALYZE TABLE t1;
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+
+INSERT INTO t1 (a00) VALUES ('bg');
+INSERT INTO t1 (a00) VALUES ('bh');
+INSERT INTO t1 (a00) VALUES ('bi');
+INSERT INTO t1 (a00) VALUES ('bj');
+INSERT INTO t1 (a00) VALUES ('bk');
+INSERT INTO t1 (a00) VALUES ('bl');
+INSERT INTO t1 (a00) VALUES ('bm');
+# Split leaf (1-7)
+# (aa,ad,ak,ar,ay,bf,bm)
+# (aa,ab,ac)(ad..)(ak..)(ar..)(ay,az,ba,bb,bc,bd,be)(bf,bg,bh,bi,bj,bk,bl)(bm)
+ANALYZE TABLE t1;
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+INSERT INTO t1 (a00) VALUES ('bn');
+INSERT INTO t1 (a00) VALUES ('bo');
+INSERT INTO t1 (a00) VALUES ('bp');
+INSERT INTO t1 (a00) VALUES ('bq');
+INSERT INTO t1 (a00) VALUES ('br');
+INSERT INTO t1 (a00) VALUES ('bs');
+INSERT INTO t1 (a00) VALUES ('bt');
+# Raise root (1-2-8)
+# (aa,ar)
+# (aa,ad,ak)            (ar,ay,bf,bm,bt)
+# (aa,ab,ac)(ad..)(ak..)(ar..)(ay..)(bf..)(bm..)(bt)
+ANALYZE TABLE t1;
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+
+INSERT INTO t1 (a00) VALUES ('bu');
+INSERT INTO t1 (a00) VALUES ('bv');
+INSERT INTO t1 (a00) VALUES ('bw');
+INSERT INTO t1 (a00) VALUES ('bx');
+INSERT INTO t1 (a00) VALUES ('by');
+INSERT INTO t1 (a00) VALUES ('bz');
+INSERT INTO t1 (a00) VALUES ('ca');
+
+INSERT INTO t1 (a00) VALUES ('cb');
+INSERT INTO t1 (a00) VALUES ('cc');
+INSERT INTO t1 (a00) VALUES ('cd');
+INSERT INTO t1 (a00) VALUES ('ce');
+INSERT INTO t1 (a00) VALUES ('cf');
+INSERT INTO t1 (a00) VALUES ('cg');
+INSERT INTO t1 (a00) VALUES ('ch');
+
+INSERT INTO t1 (a00) VALUES ('ci');
+INSERT INTO t1 (a00) VALUES ('cj');
+INSERT INTO t1 (a00) VALUES ('ck');
+INSERT INTO t1 (a00) VALUES ('cl');
+INSERT INTO t1 (a00) VALUES ('cm');
+INSERT INTO t1 (a00) VALUES ('cn');
+INSERT INTO t1 (a00) VALUES ('co');
+# Split also at level 1 (1-3-11)
+# (aa,ar,co)
+# (aa,ad,ak)            (ar,ay,bf,bm,bt,ca,ch)                    (co)
+# (aa,ab,ac)(ad..)(ak..)(ar..)(ay..)(bf..)(bm..)(bt..)(ca..)(ch..)(co)
+ANALYZE TABLE t1;
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+
+INSERT INTO t1 (a00) VALUES ('cp');
+INSERT INTO t1 (a00) VALUES ('cq');
+INSERT INTO t1 (a00) VALUES ('cr');
+INSERT INTO t1 (a00) VALUES ('cs');
+INSERT INTO t1 (a00) VALUES ('ct');
+INSERT INTO t1 (a00) VALUES ('cu');
+INSERT INTO t1 (a00) VALUES ('cv');
+
+INSERT INTO t1 (a00) VALUES ('cw');
+INSERT INTO t1 (a00) VALUES ('cx');
+INSERT INTO t1 (a00) VALUES ('cy');
+INSERT INTO t1 (a00) VALUES ('cz');
+INSERT INTO t1 (a00) VALUES ('da');
+INSERT INTO t1 (a00) VALUES ('db');
+INSERT INTO t1 (a00) VALUES ('dc');
+
+INSERT INTO t1 (a00) VALUES ('dd');
+INSERT INTO t1 (a00) VALUES ('de');
+INSERT INTO t1 (a00) VALUES ('df');
+INSERT INTO t1 (a00) VALUES ('dg');
+INSERT INTO t1 (a00) VALUES ('dh');
+INSERT INTO t1 (a00) VALUES ('di');
+INSERT INTO t1 (a00) VALUES ('dj');
+
+INSERT INTO t1 (a00) VALUES ('dk');
+INSERT INTO t1 (a00) VALUES ('dl');
+INSERT INTO t1 (a00) VALUES ('dm');
+INSERT INTO t1 (a00) VALUES ('dn');
+INSERT INTO t1 (a00) VALUES ('do');
+INSERT INTO t1 (a00) VALUES ('dp');
+INSERT INTO t1 (a00) VALUES ('dq');
+
+INSERT INTO t1 (a00) VALUES ('dr');
+INSERT INTO t1 (a00) VALUES ('ds');
+INSERT INTO t1 (a00) VALUES ('dt');
+INSERT INTO t1 (a00) VALUES ('du');
+INSERT INTO t1 (a00) VALUES ('dv');
+INSERT INTO t1 (a00) VALUES ('dw');
+INSERT INTO t1 (a00) VALUES ('dx');
+
+INSERT INTO t1 (a00) VALUES ('dy');
+INSERT INTO t1 (a00) VALUES ('dz');
+INSERT INTO t1 (a00) VALUES ('ea');
+INSERT INTO t1 (a00) VALUES ('eb');
+INSERT INTO t1 (a00) VALUES ('ec');
+INSERT INTO t1 (a00) VALUES ('ed');
+INSERT INTO t1 (a00) VALUES ('ee');
+
+INSERT INTO t1 (a00) VALUES ('ef');
+INSERT INTO t1 (a00) VALUES ('eg');
+INSERT INTO t1 (a00) VALUES ('eh');
+INSERT INTO t1 (a00) VALUES ('ei');
+INSERT INTO t1 (a00) VALUES ('ej');
+INSERT INTO t1 (a00) VALUES ('ek');
+INSERT INTO t1 (a00) VALUES ('el');
+# Split also at level 1 (1-4-18)
+# (aa,ar,co,el)
+# (aa,ad,ak)            (ar,ay,bf,bm,bt,ca,ch)                    (co,cv,dc,dj,dq,dx,ee)                    (el)
+# (aa,ab,ac)(ad..)(ak..)(ar..)(ay..)(bf..)(bm..)(bt..)(ca..)(ch..)(co..)(cv..)(dc..)(dj..)(dq..)(dx..)(ee..)(el)
+ANALYZE TABLE t1;
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+INSERT INTO t1 (a00) VALUES ('em');
+INSERT INTO t1 (a00) VALUES ('en');
+INSERT INTO t1 (a00) VALUES ('eo');
+INSERT INTO t1 (a00) VALUES ('ep');
+INSERT INTO t1 (a00) VALUES ('eq');
+INSERT INTO t1 (a00) VALUES ('er');
+INSERT INTO t1 (a00) VALUES ('es');
+
+INSERT INTO t1 (a00) VALUES ('et');
+INSERT INTO t1 (a00) VALUES ('eu');
+INSERT INTO t1 (a00) VALUES ('ev');
+INSERT INTO t1 (a00) VALUES ('ew');
+INSERT INTO t1 (a00) VALUES ('ex');
+INSERT INTO t1 (a00) VALUES ('ey');
+INSERT INTO t1 (a00) VALUES ('ez');
+
+INSERT INTO t1 (a00) VALUES ('fa');
+INSERT INTO t1 (a00) VALUES ('fb');
+INSERT INTO t1 (a00) VALUES ('fc');
+INSERT INTO t1 (a00) VALUES ('fd');
+INSERT INTO t1 (a00) VALUES ('fe');
+INSERT INTO t1 (a00) VALUES ('ff');
+INSERT INTO t1 (a00) VALUES ('fg');
+
+INSERT INTO t1 (a00) VALUES ('fh');
+INSERT INTO t1 (a00) VALUES ('fi');
+INSERT INTO t1 (a00) VALUES ('fj');
+INSERT INTO t1 (a00) VALUES ('fk');
+INSERT INTO t1 (a00) VALUES ('fl');
+INSERT INTO t1 (a00) VALUES ('fm');
+INSERT INTO t1 (a00) VALUES ('fn');
+
+INSERT INTO t1 (a00) VALUES ('fo');
+INSERT INTO t1 (a00) VALUES ('fp');
+INSERT INTO t1 (a00) VALUES ('fq');
+INSERT INTO t1 (a00) VALUES ('fr');
+INSERT INTO t1 (a00) VALUES ('fs');
+INSERT INTO t1 (a00) VALUES ('ft');
+INSERT INTO t1 (a00) VALUES ('fu');
+
+INSERT INTO t1 (a00) VALUES ('fv');
+INSERT INTO t1 (a00) VALUES ('fw');
+INSERT INTO t1 (a00) VALUES ('fx');
+INSERT INTO t1 (a00) VALUES ('fy');
+INSERT INTO t1 (a00) VALUES ('fz');
+INSERT INTO t1 (a00) VALUES ('ga');
+INSERT INTO t1 (a00) VALUES ('gb');
+
+INSERT INTO t1 (a00) VALUES ('gc');
+INSERT INTO t1 (a00) VALUES ('gd');
+INSERT INTO t1 (a00) VALUES ('ge');
+INSERT INTO t1 (a00) VALUES ('gf');
+INSERT INTO t1 (a00) VALUES ('gg');
+INSERT INTO t1 (a00) VALUES ('gh');
+
+
+# Current tree form (1-4-24)
+# (aa,ar,co,el)
+# (aa,ad,ak)            (ar,ay,bf,bm,bt,ca,ch)                    (co,cv,dc,dj,dq,dx,ee)                    (el..,gb)
+# (aa,ab,ac)(ad..)(ak..)(ar..)(ay..)(bf..)(bm..)(bt..)(ca..)(ch..)(co..)(cv..)(dc..)(dj..)(dq..)(dx..)(ee..)(el..)..(gb..)
+ANALYZE TABLE t1;
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+
+
+# Insert the rest of records normally
+SET GLOBAL innodb_limit_optimistic_insert_debug = 0;
+
+
+--echo # Test start
+
+# (1) Insert records to leaf page (bf..) and cause modify_page.
+#     - root page is not X latched
+#     - latched from level 1 page (ar,ay,bf,bm,bt,ca,ch)
+
+SET DEBUG_SYNC = 'RESET';
+
+# Filling leaf page (bf..)
+INSERT INTO t1 (a00) VALUES ('bfa');
+
+--connection con1
+SET DEBUG_SYNC = 'before_insert_pessimitic_row_ins_clust SIGNAL reached WAIT_FOR continue';
+# Cause modify_tree
+--send
+INSERT INTO t1 (a00) VALUES ('bfb');
+
+--connection con2
+SET DEBUG_SYNC = 'now WAIT_FOR reached';
+# Not blocked searches
+SELECT a00,a01 FROM t1 WHERE a00 = 'aa';
+SELECT a00,a01 FROM t1 WHERE a00 = 'aq';
+# "where a00 = 'co'" is blocked because searching from smaller ('co','a','a',..).
+SELECT a00,a01 FROM t1 WHERE a00 = 'cp';
+SELECT a00,a01 FROM t1 WHERE a00 = 'el';
+
+SET DEBUG_SYNC = 'rw_s_lock_waiting SIGNAL lockwait1';
+# Blocked
+--send
+SELECT a00,a01 FROM t1 WHERE a00 = 'ar';
+
+--connection con3
+SET DEBUG_SYNC = 'rw_s_lock_waiting SIGNAL lockwait2';
+# Blocked
+--send
+SELECT a00,a01 FROM t1 WHERE a00 = 'cn';
+
+--connection default
+# FIXME: These occasionally time out!
+--disable_warnings
+SET DEBUG_SYNC = 'now WAIT_FOR lockwait1 TIMEOUT 1';
+SET DEBUG_SYNC = 'now WAIT_FOR lockwait2 TIMEOUT 1';
+--enable_warnings
+SET DEBUG_SYNC = 'now SIGNAL continue';
+
+--connection con1
+--reap
+
+--connection con2
+--reap
+
+--connection con3
+--reap
+
+--connection default
+
+ANALYZE TABLE t1;
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+
+
+# (2) Insert records to leaf page (co..) and cause modify_page
+#     - root page is X latched, because node_ptr for 'co'
+#       is 1st record for (co,cv,dc,dj,dq,dx,ee)
+#
+# * ordinary pessimitic insert might be done by pessistic update
+#   and we should consider possibility node_ptr to be deleted.
+
+SET DEBUG_SYNC = 'RESET';
+
+# Filling leaf page (co..)
+INSERT INTO t1 (a00) VALUES ('coa');
+
+--connection con1
+SET DEBUG_SYNC = 'before_insert_pessimitic_row_ins_clust SIGNAL reached WAIT_FOR continue';
+# Cause modify_tree
+--send
+INSERT INTO t1 (a00) VALUES ('cob');
+
+--connection con2
+SET DEBUG_SYNC = 'now WAIT_FOR reached';
+# All searches are blocked because root page is X latched
+
+SET DEBUG_SYNC = 'rw_s_lock_waiting SIGNAL lockwait1';
+# Blocked
+--send
+SELECT a00,a01 FROM t1 WHERE a00 = 'aa';
+
+--connection con3
+SET DEBUG_SYNC = 'rw_s_lock_waiting SIGNAL lockwait2';
+# Blocked
+--send
+SELECT a00,a01 FROM t1 WHERE a00 = 'el';
+
+--connection default
+# FIXME: These occasionally time out!
+--disable_warnings
+SET DEBUG_SYNC = 'now WAIT_FOR lockwait1 TIMEOUT 1';
+SET DEBUG_SYNC = 'now WAIT_FOR lockwait2 TIMEOUT 1';
+--enable_warnings
+SET DEBUG_SYNC = 'now SIGNAL continue';
+
+--connection con1
+--reap
+
+--connection con2
+--reap
+
+--connection con3
+--reap
+
+--connection default
+
+ANALYZE TABLE t1;
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+
+
+# (3) Insert records to rightmost leaf page (gb..) and cause modify_page
+#     - root page is not X latched, because node_ptr for 'gb' is the last record
+#       of the level 1 though it is last record in the page.
+#     - lathed from level 1 page (el..,gb)
+
+SET DEBUG_SYNC = 'RESET';
+
+# Filling leaf page (gb..)
+INSERT INTO t1 (a00) VALUES ('gba');
+
+--connection con1
+SET DEBUG_SYNC = 'before_insert_pessimitic_row_ins_clust SIGNAL reached WAIT_FOR continue';
+# Cause modify_tree
+--send
+INSERT INTO t1 (a00) VALUES ('gbb');
+
+--connection con2
+SET DEBUG_SYNC = 'now WAIT_FOR reached';
+# Not blocked searches
+SELECT a00,a01 FROM t1 WHERE a00 = 'aa';
+SELECT a00,a01 FROM t1 WHERE a00 = 'ek';
+
+SET DEBUG_SYNC = 'rw_s_lock_waiting SIGNAL lockwait1';
+# Blocked
+--send
+SELECT a00,a01 FROM t1 WHERE a00 = 'el';
+
+--connection con3
+SET DEBUG_SYNC = 'rw_s_lock_waiting SIGNAL lockwait2';
+# Blocked
+--send
+SELECT a00,a01 FROM t1 WHERE a00 = 'gb';
+
+--connection default
+# FIXME: These occasionally time out!
+--disable_warnings
+SET DEBUG_SYNC = 'now WAIT_FOR lockwait1 TIMEOUT 1';
+SET DEBUG_SYNC = 'now WAIT_FOR lockwait2 TIMEOUT 1';
+--enable_warnings
+SET DEBUG_SYNC = 'now SIGNAL continue';
+
+--connection con1
+--reap
+
+--connection con2
+--reap
+
+--connection con3
+--reap
+
+--connection default
+ANALYZE TABLE t1;
+SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+
+
+# Cleanup
+SET DEBUG_SYNC = 'RESET';
+
+--connection default
+--disconnect con1
+--disconnect con2
+--disconnect con3
+
+DROP TABLE t1;
+
+--disable_query_log
+SET GLOBAL innodb_limit_optimistic_insert_debug = @old_innodb_limit_optimistic_insert_debug;
+SET GLOBAL innodb_adaptive_hash_index = @old_innodb_adaptive_hash_index;
+SET GLOBAL innodb_stats_persistent = @old_innodb_stats_persistent;
+--enable_query_log
+
+# Wait till all disconnects are completed.
+--source include/wait_until_count_sessions.inc
diff --git a/mysql-test/suite/innodb/t/innodb_wl6326_big.test b/mysql-test/suite/innodb/t/innodb_wl6326_big.test
new file mode 100644
index 00000000000..6d4b07e7cb6
--- /dev/null
+++ b/mysql-test/suite/innodb/t/innodb_wl6326_big.test
@@ -0,0 +1,716 @@
+# This is a script for MTR with hybrid use.
+# a) As regression test
+#    Mostly some brute force attempt to stress the internal sx locks of
+#    InnoDB which were introduced by WL#6326+WL#6363.
+#    The file with expected results fits to this variant.
+#    The impact on code coverage is quite good.
+# b) As testbed for attempts to extend or improve the RQG test wl6326_sql.yy.
+#    The MTR based test uses
+#     - a table t1 with the same layout
+#     - the same stored functions
+#     - the same stored procedure proc_fill_t1 for inserting a configurable
+#       amount of records into t1
+#    like the RQG test wl6326_sql.yy.
+#    Feel free to modify parameters like $max_row_count, $max_con,
+#    $high_load_duration or switch debugging on (let $test_debug= 1).
+#    But please be aware that MTR will most probably report that the test
+#    failed because it got a difference to expected results.
+#    Reasons:
+#    - In general: The file with expected results fits to a) only.
+#    - The actual results might dependend on $max_row_count.
+#    - Additional result sets might be printed.
+#
+
+# WL#6326 is about the sx locks (InnoDB feature only).
+--source include/have_innodb.inc
+# Runtime properties:
+# Notebook i5 dual core with HT, MySQL binaries compiled with debug,
+#          max_row_count=10000 rows
+# vardir on tmpfs : ~ 375
+# vardir on disk  : ~ 546
+--source include/big_test.inc
+# We go with "--send" and "--reap" and that fails with the embedded server.
+--source include/not_embedded.inc
+# Its intentional to not take the risk that a run with valgrind times out.
+--source include/not_valgrind.inc
+
+# FIXME:
+#    Increase the code coverage provided by the current test by
+#    trying "InnoDB Tablespace Monitor" as soon as some bug is fixed
+#    or wait till the deprecated "InnoDB Tablespace Monitor" is
+#    removed.
+
+# Setup of some parameters
+# ------------------------
+# Number of records within every chunk to be added to t1.
+let $load_unit= 10000;
+#
+# Rough number of records in t1 to achieve.
+#    We add chunks of $load_unit rows till the actual number
+#    of rows in the table t1 exceeds $max_row_count.
+# let $max_row_count= 1000000;
+# let $max_row_count= 300000;
+# let $max_row_count= 100000;
+# let $max_row_count= 30000;
+  let $max_row_count= 10000;        # ~ 322s  on tmpfs (NB)
+#
+# Determine which variant to run.
+let $test_debug= 0;
+#
+# Number of concurrent sessions to be used in the high load test.
+let $max_con=            10;
+# Duration of the high load test in seconds.
+let $high_load_duration= 60;
+
+# Putting all objects into the SCHEMA my_schema makes the final cleanup easier.
+# We simply run than DROP SCHEMA my_schema.
+CREATE SCHEMA my_schema;
+USE my_schema;
+CREATE FUNCTION f_thread_id (i INT) RETURNS CHAR(4) DETERMINISTIC
+RETURN CONCAT(LPAD(CAST(i AS CHAR),3,'_'),'_') ;
+SELECT CONCAT('->', f_thread_id( 1), '<-');
+SELECT CONCAT('->', f_thread_id(12), '<-');
+
+# Definition of parameters used in functions.
+# We use here a "1" in order to make the impact on the results of the functions
+# good visible.
+SET @extra_int    = 1;
+SET @extra_string = f_thread_id(@extra_int);
+SELECT @extra_int , @extra_string;
+
+# The different functions are used later when filling t1 and also during
+# RQG testing. They serve to generate the difference between column values
+# in different rows in different areas of the column.
+# Fictional example:
+#    row 1 col_int0=1 colx='1abcdefgh' coly='abcd1efgh' colz='abcdefgh1'
+#    row 2 col_int0=2 colx='2abcdefgh' coly='abcd2efgh' colz='abcdefgh2'
+# The function f_<pattern> is for the column with the name <pattern>.
+# There is a function
+# - for every column except col_int0
+# - even if the SQL for generating the value is simple.
+# The reason for this is the architecture of the RQG test.
+
+let $part= AS my_result
+FROM (SELECT 1 AS my_col UNION SELECT 12 UNION SELECT 123
+UNION SELECT 1234 UNION SELECT 12345) AS tx;
+
+let $function_name= f_col_int1;
+eval CREATE FUNCTION $function_name (i INT) RETURNS INT(20) DETERMINISTIC
+RETURN i * 1000 + @extra_int ;
+eval SELECT $function_name(my_col) $part;
+
+let $function_name= f_col_int2;
+eval CREATE FUNCTION $function_name (i INT) RETURNS INT(20) DETERMINISTIC
+RETURN @extra_int * 10000000 + i ;
+eval SELECT $function_name(my_col) $part;
+
+let $function_name= f_col_int3;
+eval CREATE FUNCTION $function_name (i INT) RETURNS INT(20) DETERMINISTIC
+RETURN @extra_int ;
+eval SELECT $function_name(my_col) $part;
+
+let $function_name= f_col_blob;
+eval CREATE FUNCTION $function_name (i INT) RETURNS BLOB DETERMINISTIC
+RETURN RPAD(@extra_string,(@@innodb_page_size / 2 ) + 1,'a');
+eval SELECT CONCAT('->', SUBSTR($function_name(my_col) FROM 1 FOR 10),
+     '<-.....->', SUBSTR($function_name(my_col) FROM -10 FOR 10), '<-') $part;
+
+let $function_name= f_col_char0;
+eval CREATE FUNCTION $function_name (i INT) RETURNS CHAR(255) DETERMINISTIC
+RETURN LPAD(CAST(i AS CHAR),255,' ');
+eval SELECT CONCAT('->', $function_name(my_col), '<-') $part;
+
+let $function_name= f_col_char1;
+eval CREATE FUNCTION $function_name (i INT) RETURNS CHAR(26) DETERMINISTIC
+RETURN
+CONCAT('B',
+   LPAD(SUBSTR(CAST(i AS CHAR),1,(LENGTH(CAST(i AS CHAR)) DIV 2)),10,' '),
+   @extra_string,
+   RPAD(SUBSTR(CAST(i AS CHAR), -((LENGTH(CAST(i AS CHAR)) + 1) DIV 2)),10,' '),
+   'E') ;
+eval SELECT CONCAT('->', $function_name(my_col), '<-') $part;
+
+let $function_name= f_col_char2;
+eval CREATE FUNCTION $function_name (i INT) RETURNS CHAR(26) DETERMINISTIC
+RETURN
+CONCAT('B',
+   RPAD(SUBSTR(CAST(i AS CHAR),1,(LENGTH(CAST(i AS CHAR)) DIV 2)),10,' '),
+   @extra_string,
+   LPAD(SUBSTR(CAST(i AS CHAR), -((LENGTH(CAST(i AS CHAR)) + 1) DIV 2)),10,' '),
+   'E');
+eval SELECT CONCAT('->', $function_name(my_col), '<-') $part;
+
+let $function_name= f_col_char3;
+eval CREATE FUNCTION $function_name (i INT) RETURNS CHAR(26) DETERMINISTIC
+RETURN
+CONCAT('B',@extra_string,LPAD(CAST(i AS CHAR),20,' '),'E');
+eval SELECT CONCAT('->', $function_name(my_col), '<-') $part;
+
+let $function_name= f_col_char4;
+eval CREATE FUNCTION $function_name (i INT) RETURNS CHAR(26) DETERMINISTIC
+RETURN
+CONCAT('B',RPAD(CAST(i AS CHAR),20,' '),@extra_string,'E');
+eval SELECT CONCAT('->', $function_name(my_col), '<-') $part;
+
+# Auxiliary table for figuring out the impact of scenarios on
+# information_schema.innodb_metrics content.
+CREATE TABLE my_metrics LIKE information_schema.innodb_metrics;
+ALTER TABLE my_metrics ADD COLUMN phase ENUM('after', 'before'),
+DROP COLUMN SUBSYSTEM, DROP COLUMN TYPE, DROP COLUMN COMMENT,
+ADD PRIMARY KEY (NAME,phase);
+let $empty_my_metrics= DELETE FROM my_metrics;
+let $before_my_metrics= INSERT INTO my_metrics
+SELECT NAME, COUNT, MAX_COUNT, MIN_COUNT, AVG_COUNT,
+COUNT_RESET, MAX_COUNT_RESET, MIN_COUNT_RESET, AVG_COUNT_RESET,
+TIME_ENABLED, TIME_DISABLED, TIME_ELAPSED, TIME_RESET,
+STATUS, 'before'
+FROM information_schema.innodb_metrics
+WHERE NAME LIKE 'innodb_rwlock_sx_%';
+let $after_my_metrics= INSERT INTO my_metrics
+SELECT NAME, COUNT, MAX_COUNT, MIN_COUNT, AVG_COUNT,
+COUNT_RESET, MAX_COUNT_RESET, MIN_COUNT_RESET, AVG_COUNT_RESET,
+TIME_ENABLED, TIME_DISABLED, TIME_ELAPSED, TIME_RESET,
+STATUS, 'after'
+FROM information_schema.innodb_metrics
+WHERE NAME LIKE 'innodb_rwlock_sx_%';
+let $print_metrics= SELECT NAME, COUNT, MAX_COUNT, MIN_COUNT, AVG_COUNT,
+COUNT_RESET, MAX_COUNT_RESET, MIN_COUNT_RESET, AVG_COUNT_RESET,
+TIME_ENABLED, TIME_DISABLED, TIME_ELAPSED, TIME_RESET, STATUS
+FROM information_schema.innodb_metrics
+WHERE NAME LIKE 'innodb_rwlock_sx_%'
+ORDER BY NAME;
+
+# The main table for testing.
+CREATE TABLE t1 (
+   col_int0 BIGINT,
+   col_int1 BIGINT,
+   col_int2 BIGINT,
+   col_int3 BIGINT,
+   col_blob BLOB,
+   col_char0 VARCHAR(255),
+   col_char1 VARCHAR(30),
+   col_char2 VARCHAR(30),
+   col_char3 VARCHAR(30),
+   col_char4 VARCHAR(30)
+) ENGINE = InnoDB;
+
+# Use many indexes with mostly significant size in order to cause
+# some heavy use of sx locks during data generation.
+ALTER TABLE t1 ADD UNIQUE KEY uidx_col_int0 (col_int0),
+ADD UNIQUE KEY uidx1 (col_int1, col_char0),
+ADD UNIQUE KEY uidx2 (col_int2, col_char0, col_int1),
+ADD UNIQUE KEY uidx3 (col_int3, col_int2, col_char0),
+ADD UNIQUE KEY uidx4 (col_char1, col_char0),
+ADD UNIQUE KEY uidx5 (col_char2, col_char0, col_char1),
+ADD UNIQUE KEY uidx6 (col_char3, col_char2, col_char0),
+ADD UNIQUE KEY uidx7 (col_int1, col_int2, col_int3, col_char4,
+                 col_char1, col_char2, col_char3, col_char0),
+ADD KEY idx8 (col_blob(10), col_char4);
+
+delimiter |;
+CREATE PROCEDURE proc_fill_t1 (max_row_count INT, load_unit INT)
+BEGIN
+   DECLARE my_count INTEGER DEFAULT 0;
+   DECLARE max_load_count INTEGER DEFAULT 0;
+   DROP TABLE IF EXISTS t0;
+   CREATE TEMPORARY TABLE t0 (col_int0 BIGINT, PRIMARY KEY(col_int0));
+   WHILE (my_count < load_unit ) DO
+      SET my_count = my_count + 1;
+      INSERT INTO t0 SET col_int0 = my_count;
+   END WHILE;
+   SET max_load_count = (SELECT (max_row_count DIV load_unit) + 1 );
+   SELECT COUNT(col_int0) INTO @val FROM t1;
+   SET my_count = 0;
+   REPEAT
+      INSERT INTO t1 (col_int0, col_int1, col_int2, col_int3, col_blob,
+                      col_char0, col_char1, col_char2,col_char3,col_char4)
+      SELECT col_int0 + @val,
+             f_col_int1(col_int0 + @val),
+             f_col_int2(col_int0 + @val),
+             f_col_int3(col_int0 + @val),
+             f_col_blob(col_int0 + @val),
+             f_col_char0(col_int0 + @val),
+             f_col_char1(col_int0 + @val),
+             f_col_char2(col_int0 + @val),
+             f_col_char3(col_int0 + @val),
+             f_col_char4(col_int0 + @val)
+      FROM t0;
+      COMMIT;
+      SELECT MAX(col_int0) INTO @val FROM t1;
+      SET my_count = my_count + 1;
+   UNTIL( my_count > max_load_count OR @val >= max_row_count )
+   END REPEAT;
+   DROP TEMPORARY TABLE t0;
+END|
+delimiter ;|
+
+delimiter |;
+CREATE PROCEDURE proc_dml (max_duration INT, t1_stripe_half INT)
+BEGIN
+   DECLARE aux INTEGER DEFAULT 0;
+   DECLARE start_time INT;
+   DECLARE CONTINUE HANDLER FOR SQLEXCEPTION, SQLWARNING, NOT FOUND BEGIN END;
+
+   SET @extra_int    = CONNECTION_ID();
+   SET @extra_string = f_thread_id(@extra_int);
+   SELECT ROUND(MAX(col_int0) / 2 ) INTO @t1_half FROM t1;
+   # The user lock 'Blocker' should be already set by some other session S1.
+   # S1 starts the race by releasing that lock.
+   # Wait till the lock is released and the lock can be obtained.
+   # In order to prevent endless waiting in case of non foreseen problems
+   # limit the timespan to 30 seconds.
+   SELECT GET_LOCK('Blocker', 30) INTO @aux;
+   # Release the lock immediate so that the other "runner" sessions start too.
+   SELECT RELEASE_LOCK('Blocker') INTO @aux;
+   SET start_time = UNIX_TIMESTAMP();
+
+   WHILE (UNIX_TIMESTAMP() - start_time < max_duration) DO
+      SET @aux = @t1_half - t1_stripe_half + ROUND(RAND() * t1_stripe_half * 2);
+      UPDATE t1 SET
+         col_int1  = f_col_int1(col_int0),
+         col_int2  = f_col_int2(col_int0),
+         col_int3  = f_col_int3(col_int0),
+         col_blob  = f_col_blob(col_int0),
+         col_char0 = f_col_char0(col_int0),
+         col_char1 = f_col_char1(col_int0),
+         col_char2 = f_col_char2(col_int0),
+         col_char3 = f_col_char3(col_int0),
+         col_char4 = f_col_char4(col_int0)
+      WHERE col_int0 = @aux;
+      COMMIT;
+   END WHILE;
+END|
+delimiter ;|
+
+SET GLOBAL innodb_monitor_disable = "innodb_rwlock_sx_%";
+SET @pre_reset_ts = NOW();
+--sleep 1.1
+SET GLOBAL innodb_monitor_reset   = "innodb_rwlock_sx_%";
+SET @pre_enable_ts = NOW();
+--sleep 1.1
+SET GLOBAL innodb_monitor_enable  = "innodb_rwlock_sx_%";
+--sleep 1.1
+SET @pre_collect_ts = NOW();
+eval $empty_my_metrics;
+eval $before_my_metrics;
+--echo # TC-01 There are exact three entries "innodb_rwlock_sx_%" with the
+--echo #       with the name which follow in innodb_metrics.
+let $check_statement=
+SELECT COUNT(*) <> 3 FROM my_metrics
+WHERE NAME IN ('innodb_rwlock_sx_spin_waits',
+               'innodb_rwlock_sx_spin_rounds',
+               'innodb_rwlock_sx_os_waits');
+if(`$check_statement`)
+{
+   --echo #    fail
+   eval $check_statement;
+   SELECT NAME FROM my_metrics
+   ORDER BY NAME;
+   exit;
+}
+--echo #    pass
+
+SELECT COUNT(*) INTO @sx_count FROM my_metrics;
+
+--echo # TC-02 Counting is now enabled. ALL = @sx_count entries show that.
+let $check_statement=
+SELECT COUNT(*) <> @sx_count FROM my_metrics
+WHERE STATUS = 'enabled';
+if(`$check_statement`)
+{
+   --echo #    fail
+   eval $check_statement;
+   SELECT NAME, STATUS FROM my_metrics
+   ORDER BY NAME;
+   exit;
+}
+--echo #    pass
+
+--echo # TC-03 @pre_reset_ts < TIME_RESET. ALL = @sx_count entries show that.
+let $check_statement=
+SELECT COUNT(*) <> @sx_count FROM my_metrics
+WHERE @pre_reset_ts < TIME_RESET;
+if(`$check_statement`)
+{
+   --echo #    fail
+   eval $check_statement;
+   SELECT NAME, @pre_reset_ts, TIME_RESET FROM my_metrics
+   ORDER BY NAME;
+   exit;
+}
+--echo #    pass
+
+--echo # TC-04 @pre_enable_ts < TIME_ENABLED. ALL = @sx_count entries show that.
+let $check_statement=
+SELECT COUNT(*) <> @sx_count FROM my_metrics
+WHERE @pre_enable_ts < TIME_ENABLED;
+if(`$check_statement`)
+{
+   --echo #    fail
+   eval $check_statement;
+   SELECT NAME, @pre_enable_ts, TIME_ENABLED FROM my_metrics
+   ORDER BY NAME;
+   exit;
+}
+--echo #    pass
+
+--echo # TC-05 TIME_RESET < TIME_ENABLED AND TIME_ENABLED < @pre_collect_ts
+--echo #       AND TIME_ELAPSED > 0. ALL = @sx_count entries show that.
+let $check_statement=
+SELECT COUNT(*) <> @sx_count FROM my_metrics
+WHERE TIME_RESET < TIME_ENABLED AND TIME_ENABLED < @pre_collect_ts
+  AND TIME_ELAPSED > 0;
+if(`$check_statement`)
+{
+   --echo #    fail
+   eval $check_statement;
+   SELECT NAME, @pre_collect_ts, TIME_RESET, TIME_ENABLED, TIME_ELAPSED
+   FROM my_metrics
+   ORDER BY NAME;
+   exit;
+}
+--echo #    pass
+
+--echo # TC-06 COUNT_RESET = MAX_COUNT_RESET. ALL = @sx_count entries show that.
+let $check_statement=
+SELECT COUNT(*) <> @sx_count FROM my_metrics
+WHERE COUNT_RESET = MAX_COUNT_RESET;
+if(`$check_statement`)
+{
+   --echo #    fail
+   eval $check_statement;
+   SELECT NAME, COUNT_RESET, MAX_COUNT_RESET FROM my_metrics
+   ORDER BY NAME;
+   exit;
+}
+--echo #    pass
+
+SET GLOBAL innodb_monitor_reset = "innodb_rwlock_sx_%";
+--disable_result_log
+if($test_debug)
+{
+   --enable_result_log
+   eval $print_metrics;
+}
+SHOW ENGINE INNODB STATUS;
+--enable_result_log
+
+eval $empty_my_metrics;
+eval $before_my_metrics;
+# These values (the "0") help to identify later if some record is in its
+# initial state or already modified.
+SET @extra_string = '__0_';
+SET @extra_int    =    0;
+
+--echo # TC-07 One session inserts some significant amount of rows into t1.
+--echo #       The system MUST survive that.
+--replace_result $max_row_count <max_row_count>
+eval SET @max_row_count = $max_row_count;
+--replace_result $load_unit <load_unit>
+eval SET @load_unit = $load_unit;
+SET @start_time = UNIX_TIMESTAMP();
+SET AUTOCOMMIT = OFF;
+CALL proc_fill_t1 (@max_row_count, @load_unit);
+--echo #    pass
+SET AUTOCOMMIT = ON;
+SELECT col_int0 INTO @t1_half FROM t1
+WHERE col_int0 >= (@val DIV 2) ORDER BY col_int0 LIMIT 1;
+
+--disable_result_log
+if($test_debug)
+{
+   --enable_result_log
+   SELECT COUNT(*) AS table_row_count,
+          UNIX_TIMESTAMP() - @start_time AS fill_run_time
+   FROM t1;
+   eval $print_metrics;
+}
+SHOW ENGINE INNODB STATUS;
+--enable_result_log
+
+# Show that the value distribution is according to the plan.
+--vertical_results
+SELECT col_int0, col_int1, col_int2, col_int3,
+   CONCAT('->', SUBSTR(col_blob FROM 1 FOR 10),
+     '<-.....->', SUBSTR(col_blob FROM -10 FOR 10), '<-') AS  col_blobx,
+   CONCAT('->',col_char0,'<-') AS col_char0x,
+   CONCAT('->',col_char1,'<-') AS col_char1x,
+   CONCAT('->',col_char2,'<-') AS col_char2x,
+   CONCAT('->',col_char3,'<-') AS col_char3x,
+   CONCAT('->',col_char4,'<-') AS col_char4x
+FROM t1 WHERE col_int0 between 98 AND 102;
+--horizontal_results
+
+# For experiments/interest only. Please do not remove that.
+if (0)
+{
+   ANALYZE TABLE t1;
+   SELECT n_rows, clustered_index_size, sum_of_other_index_sizes
+   FROM mysql.innodb_table_stats;
+
+   # SELECT * FROM mysql.innodb_index_stats;
+   # idx_col_int3_int0  n_diff_pfx01      1  col_int3
+   # idx_col_int3_int0  n_diff_pfx02  10000  col_int3,col_int0
+   # idx_col_int3_int0  n_diff_pfx03  10000  col_int3,col_int0,DB_ROW_ID
+   # idx_col_int3_int0  n_leaf_pages     19  Number of leaf pages in the index
+   # idx_col_int3_int0  size             20  Number of pages in the index
+
+   --vertical_results
+   SELECT t1.index_name, t1.stat_value AS idx_pages, t2.stat_value AS idx_leaf_pages,
+          (t1.stat_value - t2.stat_value - 1) / t1.stat_value AS sx_page_ratio
+   FROM mysql.innodb_index_stats t1, mysql.innodb_index_stats t2
+   WHERE t1.index_name = t2.index_name
+     AND t1.stat_name = 'size' AND t2.stat_name = 'n_leaf_pages'
+   ORDER BY t1.index_name;
+   --horizontal_results
+}
+
+--echo # TC-11 Several concurrent sessions perform updates in t1 like mad.
+--echo #       The system MUST survive this.
+--echo #       Printing of statements is partially suppressed.
+SET @start_time = UNIX_TIMESTAMP();
+SELECT 1 FROM t1 WHERE col_int0 = @t1_half FOR UPDATE;
+SELECT GET_LOCK('Blocker', 1000) ;
+--disable_query_log
+let $num= $max_con;
+while ($num)
+{
+   --connect (con$num,localhost,root,,)
+   USE my_schema;
+   # The second parameter of the procedure is size of the affected stripe / 2.
+   # A smaller stripe causes some smaller counter growth but most probably
+   # also more stress around locking in general.
+   # Example # (nnnn) = half stripe size
+   # NAME                         | COUNT_RESET (5000) | COUNT_RESET (100)
+   # -----------------------------+--------------------+----------------
+   # innodb_rwlock_sx_os_waits    |        1412        |         486
+   # innodb_rwlock_sx_spin_rounds |       44061        |       17031
+   # innodb_rwlock_sx_spin_waits  |         996        |         515
+   --send
+   eval CALL proc_dml($high_load_duration,@t1_half);
+   dec $num;
+}
+--connection default
+SELECT RELEASE_LOCK('Blocker') ;
+--sleep 3
+COMMIT;
+let $num= $max_con;
+while ($num)
+{
+   --connection con$num
+   --reap
+   dec $num;
+}
+--echo #    pass
+--connection default
+--enable_query_log
+
+# let $wait_timeout= 181;
+# --source include/wait_condition.inc
+# eval $after_my_metrics;
+--disable_result_log
+if($test_debug)
+{
+   --enable_result_log
+   SELECT UNIX_TIMESTAMP() - @start_time AS update_battle_run_time;
+   eval $print_metrics;
+}
+SHOW ENGINE INNODB STATUS;
+--enable_result_log
+
+--echo # TC-13 One session performs ALTER TABLE t1 ADD KEY ... on the fat table t1.
+--echo #       The system MUST survive this.
+SET @start_time = UNIX_TIMESTAMP();
+ALTER TABLE t1 ADD KEY idx_col_char4_col_char0 (col_char4,col_char0);
+--disable_result_log
+if($test_debug)
+{
+   --enable_result_log
+   SELECT UNIX_TIMESTAMP() - @start_time AS add_key_run_time;
+   eval $print_metrics;
+}
+SHOW ENGINE INNODB STATUS;
+--enable_result_log
+--echo #    pass
+
+--echo # TC-15 One session performs a fat update on the fat table t1.
+--echo #       The system MUST survive this.
+SET @start_time   = UNIX_TIMESTAMP();
+SET @extra_int    = 13;
+SET @extra_string = f_thread_id(@extra_int);
+eval UPDATE t1 SET
+   col_int1  = f_col_int1(col_int0),  col_int2  = f_col_int2(col_int0),
+   col_int3  = f_col_int3(col_int0),  col_blob  = f_col_blob(col_int0),
+   col_char0 = f_col_char0(col_int0), col_char1 = f_col_char1(col_int0),
+   col_char2 = f_col_char2(col_int0), col_char3 = f_col_char3(col_int0),
+   col_char4 = f_col_char4(col_int0)
+WHERE col_int0 BETWEEN @t1_half - 2500 AND @t1_half + 2500;
+COMMIT;
+--disable_result_log
+if($test_debug)
+{
+   --enable_result_log
+   SELECT UNIX_TIMESTAMP() - @start_time AS total_update_run_time;
+   eval $print_metrics;
+}
+SHOW ENGINE INNODB STATUS;
+--enable_result_log
+--echo #    pass
+
+# Basically every of the big activities causes some counter growth.
+# But caused by
+# - the architecture of InnoDB (certain things happen asynchronous)
+# - the actual test configuration (server/InnoDB options)
+# - conditions like parallel (./mtr --parallel=auto?) load on the testing box
+# this might be not fulfilled per single big activity every time except
+# we go with huge waits or similar.
+# Observation:
+# - non debug binaries: expectation frequent not fulfilled
+# - debug binaries:     expectation rare not fulfilled
+#
+let $wait_timeout= 121;
+let $wait_condition=
+SELECT COUNT(*) = @sx_count
+FROM information_schema.innodb_metrics t_after
+JOIN my_metrics t_before
+ON t_after.COUNT_RESET > t_before.COUNT_RESET AND t_after.NAME = t_before.NAME;
+--source include/wait_condition.inc
+eval $after_my_metrics;
+
+--echo # TC-16 The following activities happend after reset in innodb_metrics
+--echo #       - Insert some significant amount of rows into t1.
+--echo #       - Several concurrent users perform excessive updates in t1.
+--echo #       - ALTER TABLE ... ADD KEY <sufficient big enough structure>
+--echo #       - One UPDATE statement modifying a huge slice of t1.
+--echo #       Any of them causes heavy use of SX lock and therefore COUNT_RESET
+--echo #       must have grown for ALL = @sx_count entries.
+# The former testcases TC-10 and TC12 had to be made a part of this testcase
+# because their results were unstable.
+let $check_statement=
+SELECT COUNT(*) <> @sx_count FROM my_metrics t_after JOIN my_metrics t_before
+ON t_after.COUNT_RESET > t_before.COUNT_RESET AND t_after.NAME = t_before.NAME
+WHERE t_after.phase = 'after' AND t_before.phase = 'before';
+if(`$check_statement`)
+{
+   --echo #    fail
+   eval $check_statement;
+   SELECT * FROM my_metrics
+   ORDER BY NAME, phase;
+   exit;
+}
+--echo #    pass
+
+--echo # TC-09 Heavy activity after reset.
+--echo #       COUNT_RESET = MAX_COUNT_RESET for ALL = @sx_count entries
+--echo #       needs to stay valid though he counters will have grown.
+let $check_statement=
+SELECT COUNT(*) <> @sx_count FROM my_metrics
+WHERE phase = 'after' AND COUNT_RESET = MAX_COUNT_RESET;
+if(`$check_statement`)
+{
+   --echo #    fail
+   eval $check_statement;
+   SELECT * FROM my_metrics
+   ORDER BY NAME, phase;
+   exit;
+}
+--echo #    pass
+
+eval $empty_my_metrics;
+eval $before_my_metrics;
+SET GLOBAL innodb_monitor_reset = "innodb_rwlock_sx_%";
+eval $after_my_metrics;
+--echo # TC-08 There was a reset. COUNT_RESET = MAX_COUNT_RESET for ALL
+--echo #       = @sx_count entries.
+let $check_statement=
+SELECT COUNT(*) <> @sx_count FROM my_metrics
+WHERE phase = 'before' AND COUNT_RESET = MAX_COUNT_RESET;
+if(`$check_statement`)
+{
+   --echo #    fail
+   eval $check_statement;
+   SELECT * FROM my_metrics
+   ORDER BY NAME, phase;
+   exit;
+}
+--echo #    pass
+
+--echo # TC-17 We had heavy activity causing big counters and after that a reset.
+--echo #       Reset causes COUNT > COUNT_RESET AND MAX_COUNT > MAX_COUNT_RESET
+--echo #       for ALL @sx_count entries.
+let $check_statement=
+SELECT COUNT(*) <> @sx_count FROM my_metrics
+WHERE phase = 'after'
+  AND COUNT > COUNT_RESET
+  AND MAX_COUNT > MAX_COUNT_RESET;
+if(`$check_statement`)
+{
+   --echo #    fail
+   eval $check_statement;
+   SELECT * FROM my_metrics
+   ORDER BY NAME, phase;
+   exit;
+}
+--echo #    pass
+
+--echo # TC-18 We had some reset but this must not decrease COUNT or MAX_COUNT
+--echo #       after.COUNT >= before.COUNT AND
+--echo #       after.MAX_COUNT >= before.MAX_COUNT for ALL @sx_count entries.
+let $check_statement=
+SELECT COUNT(*) <> @sx_count FROM my_metrics t_after JOIN my_metrics t_before
+ON t_after.COUNT >= t_before.COUNT AND t_after.MAX_COUNT >= t_before.MAX_COUNT
+   AND t_after.NAME = t_before.NAME
+WHERE t_after.phase = 'after' AND t_before.phase = 'before';
+if(`$check_statement`)
+{
+   --echo #    fail
+   eval $check_statement;
+   SELECT * FROM my_metrics
+   ORDER BY NAME, phase;
+   exit;
+}
+--echo #    pass
+
+--echo # TC-19 We had some reset after heavy activity and this must cause
+--echo #       after.COUNT_RESET < before.COUNT_RESET
+--echo #       AND after.MAX_COUNT_RESET < before.MAX_COUNT_RESET AND
+--echo #       for ALL @sx_count entries.
+let $check_statement=
+SELECT COUNT(*) <> @sx_count FROM my_metrics t_after JOIN my_metrics t_before
+ON t_after.COUNT_RESET < t_before.COUNT_RESET
+   AND t_after.MAX_COUNT_RESET < t_before.MAX_COUNT_RESET
+   AND t_after.NAME = t_before.NAME
+WHERE t_after.phase = 'after' AND t_before.phase = 'before';
+if(`$check_statement`)
+{
+   --echo #    fail
+   eval $check_statement;
+   SELECT * FROM my_metrics
+   ORDER BY NAME, phase;
+   exit;
+}
+--echo #    pass
+
+# Cleanup
+let $num= $max_con;
+while ($num)
+{
+   --connection con$num
+   --disconnect con$num
+   --source include/wait_until_disconnected.inc
+   dec $num;
+}
+--connection default
+USE test;
+DROP SCHEMA my_schema;
+SET GLOBAL innodb_monitor_disable   = all;
+SET GLOBAL innodb_monitor_reset_all = all;
+--disable_warnings
+SET GLOBAL innodb_monitor_enable    = default;
+SET GLOBAL innodb_monitor_disable   = default;
+SET GLOBAL innodb_monitor_reset     = default;
+SET GLOBAL innodb_monitor_reset_all = default;
+--enable_warnings
+SET GLOBAL innodb_monitor_disable   = "innodb_rwlock_sx_%";
+SET GLOBAL innodb_monitor_reset     = "innodb_rwlock_sx_%";
+
diff --git a/mysql-test/suite/innodb/t/redo_log_during_checkpoint.test b/mysql-test/suite/innodb/t/redo_log_during_checkpoint.test
index 21c3c72da1c..645ae8c7855 100644
--- a/mysql-test/suite/innodb/t/redo_log_during_checkpoint.test
+++ b/mysql-test/suite/innodb/t/redo_log_during_checkpoint.test
@@ -34,8 +34,8 @@ while ($i)
 --let $_expect_file_name= $MYSQLTEST_VARDIR/tmp/mysqld.$_server_id.expect
 --exec echo "wait" > $_expect_file_name
 
-set debug_dbug = '+d,increase_mtr_checkpoint_size';
-set debug_dbug = '+d,crash_after_checkpoint';
+SET debug_dbug = '+d,increase_mtr_checkpoint_size';
+SET debug_dbug = '+d,crash_after_checkpoint';
 --error 2013
 set global innodb_log_checkpoint_now = 1;
 
@@ -65,7 +65,7 @@ while ($i)
 --enable_query_log
 
 --exec echo "wait" > $_expect_file_name
-set debug_dbug = '+d,crash_after_checkpoint';
+SET debug_dbug = '+d,crash_after_checkpoint';
 --error 2013
 set global innodb_log_checkpoint_now = 1;
 
diff --git a/mysql-test/suite/innodb_fts/r/concurrent_insert.result b/mysql-test/suite/innodb_fts/r/concurrent_insert.result
index 9871d43119a..9be7ba35f30 100644
--- a/mysql-test/suite/innodb_fts/r/concurrent_insert.result
+++ b/mysql-test/suite/innodb_fts/r/concurrent_insert.result
@@ -17,6 +17,7 @@ INSERT INTO t1 VALUES('test');
 CREATE TABLE t2 (f1 char(100), FULLTEXT idx1(f1))ENGINE=InnoDB;
 INSERT INTO t2 VALUES('mariadb');
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 SET GLOBAL debug_dbug ='+d,fts_instrument_sync_request,ib_optimize_wq_hang';
 SET DEBUG_SYNC= 'fts_instrument_sync_request
 		 SIGNAL drop_index_start WAIT_FOR sync_op';
@@ -28,7 +29,7 @@ ALTER TABLE t2 drop index idx1;
 connection default;
 set DEBUG_SYNC= 'now SIGNAL fts_drop_index';
 connection con1;
-SET global DEBUG_DBUG=RESET;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 drop table t1, t2;
 connection default;
 set DEBUG_SYNC=RESET;
diff --git a/mysql-test/suite/innodb_fts/t/concurrent_insert.test b/mysql-test/suite/innodb_fts/t/concurrent_insert.test
index 77097d44dc5..1505767d835 100644
--- a/mysql-test/suite/innodb_fts/t/concurrent_insert.test
+++ b/mysql-test/suite/innodb_fts/t/concurrent_insert.test
@@ -29,6 +29,7 @@ CREATE TABLE t2 (f1 char(100), FULLTEXT idx1(f1))ENGINE=InnoDB;
 INSERT INTO t2 VALUES('mariadb');
 
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 SET GLOBAL debug_dbug ='+d,fts_instrument_sync_request,ib_optimize_wq_hang';
 SET DEBUG_SYNC= 'fts_instrument_sync_request
 		 SIGNAL drop_index_start WAIT_FOR sync_op';
@@ -45,7 +46,7 @@ set DEBUG_SYNC= 'now SIGNAL fts_drop_index';
 
 connection con1;
 reap;
-SET global DEBUG_DBUG=RESET;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 drop table t1, t2;
 connection default;
 set DEBUG_SYNC=RESET;
diff --git a/mysql-test/suite/innodb_gis/r/rtree_debug.result b/mysql-test/suite/innodb_gis/r/rtree_debug.result
index 11e2cd40e25..e8d2418af57 100644
--- a/mysql-test/suite/innodb_gis/r/rtree_debug.result
+++ b/mysql-test/suite/innodb_gis/r/rtree_debug.result
@@ -42,7 +42,7 @@ SET @save_dbug = @@SESSION.debug_dbug;
 SET debug_dbug='+d,row_merge_ins_spatial_fail';
 create spatial index idx2 on t1(c2);
 ERROR HY000: Got error 1000 "Unknown error 1000" from storage engine InnoDB
-SET debug_dbug = @save_dbug;
+SET @@SESSION.debug_dbug = @save_dbug;
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
diff --git a/mysql-test/suite/innodb_gis/t/rtree_debug.test b/mysql-test/suite/innodb_gis/t/rtree_debug.test
index 2f7c2806c68..580f3cf48a1 100644
--- a/mysql-test/suite/innodb_gis/t/rtree_debug.test
+++ b/mysql-test/suite/innodb_gis/t/rtree_debug.test
@@ -53,7 +53,7 @@ SET @save_dbug = @@SESSION.debug_dbug;
 SET debug_dbug='+d,row_merge_ins_spatial_fail';
 --error ER_GET_ERRNO
 create spatial index idx2 on t1(c2);
-SET debug_dbug = @save_dbug;
+SET @@SESSION.debug_dbug = @save_dbug;
 show create table t1;
 
 # Check table.
diff --git a/mysql-test/suite/innodb_gis/t/rtree_rollback1.test b/mysql-test/suite/innodb_gis/t/rtree_rollback1.test
index 123bccf76a1..3dea75bc026 100644
--- a/mysql-test/suite/innodb_gis/t/rtree_rollback1.test
+++ b/mysql-test/suite/innodb_gis/t/rtree_rollback1.test
@@ -1,9 +1,6 @@
 # WL#6745 InnoDB R-tree support
 # This test case will test R-tree split.
 
-# Not supported in embedded
---source include/not_embedded.inc
-
 --source include/have_innodb.inc
 --source include/big_test.inc
 --source include/not_valgrind.inc
diff --git a/mysql-test/suite/innodb_gis/t/rtree_rollback2.test b/mysql-test/suite/innodb_gis/t/rtree_rollback2.test
index cddbaf5592d..78b251bd696 100644
--- a/mysql-test/suite/innodb_gis/t/rtree_rollback2.test
+++ b/mysql-test/suite/innodb_gis/t/rtree_rollback2.test
@@ -1,9 +1,6 @@
 # WL#6745 InnoDB R-tree support
 # This test case will test R-tree split.
 
-# Not supported in embedded
---source include/not_embedded.inc
-
 --source include/have_innodb.inc
 --source include/big_test.inc
 --source include/not_valgrind.inc
diff --git a/mysql-test/suite/innodb_zip/r/wl5522_zip.result b/mysql-test/suite/innodb_zip/r/wl5522_zip.result
index 03bfd2cac7a..80e22bef257 100644
--- a/mysql-test/suite/innodb_zip/r/wl5522_zip.result
+++ b/mysql-test/suite/innodb_zip/r/wl5522_zip.result
@@ -412,7 +412,7 @@ SELECT * FROM t1;
 ERROR HY000: Tablespace has been discarded for table `t1`
 restore: t1 .ibd and .cfg files
 ALTER TABLE t1 IMPORT TABLESPACE;
-ERROR HY000: Schema mismatch (Column c2 precise type mismatch.)
+ERROR HY000: Schema mismatch (Column c2 precise type mismatch, it's 0X408 in the table and 0X403 in the tablespace meta file)
 unlink: t1.ibd
 unlink: t1.cfg
 DROP TABLE t1;
diff --git a/mysql-test/suite/optimizer_unfixed_bugs/r/bug36981.result b/mysql-test/suite/optimizer_unfixed_bugs/r/bug36981.result
index 760d7342752..a0be9e23818 100644
--- a/mysql-test/suite/optimizer_unfixed_bugs/r/bug36981.result
+++ b/mysql-test/suite/optimizer_unfixed_bugs/r/bug36981.result
@@ -1,3 +1,4 @@
+SET @saved_dbug = @@SESSION.debug_dbug;
 set session debug_dbug="+d,optimizer_innodb_icp";
 create table `t1` (`c1` char(1) default null,`c2` char(10) default null,
 key (`c1`))
@@ -7,3 +8,4 @@ select * from `t1` where `c1`='3' for update;
 c1	c2
 3	NULL
 drop table `t1`;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/optimizer_unfixed_bugs/r/bug40992.result b/mysql-test/suite/optimizer_unfixed_bugs/r/bug40992.result
index 5e53649c538..59ab7607a40 100644
--- a/mysql-test/suite/optimizer_unfixed_bugs/r/bug40992.result
+++ b/mysql-test/suite/optimizer_unfixed_bugs/r/bug40992.result
@@ -1,6 +1,7 @@
 #
 # Bug#40992 - InnoDB: Crash when engine_condition_pushdown is on
 #
+SET @saved_dbug = @@SESSION.debug_dbug;
 set session debug_dbug="+d,optimizer_innodb_icp";
 CREATE TABLE t (
 dummy INT PRIMARY KEY, 
@@ -13,3 +14,4 @@ dummy	a	b
 3	3	3
 5	5	5
 DROP TABLE t;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/optimizer_unfixed_bugs/r/bug41996.result b/mysql-test/suite/optimizer_unfixed_bugs/r/bug41996.result
index 31e39d4421d..acc18b06ea0 100644
--- a/mysql-test/suite/optimizer_unfixed_bugs/r/bug41996.result
+++ b/mysql-test/suite/optimizer_unfixed_bugs/r/bug41996.result
@@ -1,3 +1,4 @@
+SET @saved_dbug = @@SESSION.debug_dbug;
 set session debug_dbug="+d,optimizer_innodb_icp";
 drop table if exists `t1`;
 Warnings:
@@ -6,3 +7,4 @@ create table `t1` (`c` bigint, key(`c`),`a` int)engine=innodb;
 insert into `t1` values(2,2);
 delete `t1` from `t1` `a`, `t1` where `a`.`a`=`t1`.`c` ;
 drop table `t1`;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/optimizer_unfixed_bugs/r/bug42991.result b/mysql-test/suite/optimizer_unfixed_bugs/r/bug42991.result
index e4fdf0d03a7..f5554563a18 100644
--- a/mysql-test/suite/optimizer_unfixed_bugs/r/bug42991.result
+++ b/mysql-test/suite/optimizer_unfixed_bugs/r/bug42991.result
@@ -1,3 +1,4 @@
+SET @saved_dbug = @@SESSION.debug_dbug;
 set session debug_dbug="+d,optimizer_innodb_icp";
 /*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
 /*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
@@ -252,3 +253,4 @@ Warning	1292	Truncated incorrect DOUBLE value: 'd'
 Warning	1292	Truncated incorrect DOUBLE value: 'd'
 Warning	1292	Truncated incorrect DOUBLE value: 'd'
 drop table `table5`;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/optimizer_unfixed_bugs/r/bug43249.result b/mysql-test/suite/optimizer_unfixed_bugs/r/bug43249.result
index 0cd801280c8..f6f5cd7c6fd 100644
--- a/mysql-test/suite/optimizer_unfixed_bugs/r/bug43249.result
+++ b/mysql-test/suite/optimizer_unfixed_bugs/r/bug43249.result
@@ -1,3 +1,4 @@
+SET @saved_dbug = @@SESSION.debug_dbug;
 set session debug_dbug="+d,optimizer_innodb_icp";
 CREATE TABLE t1(c1 TIME NOT NULL, c2 TIME NULL, c3 DATE, PRIMARY
 KEY(c1), UNIQUE INDEX(c2)) engine=innodb;
@@ -9,3 +10,4 @@ SELECT * FROM t1 WHERE c2 <=> NULL ORDER BY c2 LIMIT 2;
 c1	c2	c3
 08:29:45	NULL	2009-02-01
 drop table `t1`;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/optimizer_unfixed_bugs/r/bug43360.result b/mysql-test/suite/optimizer_unfixed_bugs/r/bug43360.result
index 899bf04e635..7e838906114 100644
--- a/mysql-test/suite/optimizer_unfixed_bugs/r/bug43360.result
+++ b/mysql-test/suite/optimizer_unfixed_bugs/r/bug43360.result
@@ -1,6 +1,7 @@
 #
 # Bug#43360 - Server crash with a simple multi-table update
 #
+SET @saved_dbug = @@SESSION.debug_dbug;
 set session debug_dbug="+d,optimizer_innodb_icp";
 CREATE TABLE t1 (
 a CHAR(2) NOT NULL PRIMARY KEY, 
@@ -42,3 +43,4 @@ AB	Sweden
 MS	United States of Ame
 JA	USA
 DROP TABLE t1,t2;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/optimizer_unfixed_bugs/r/bug43448.result b/mysql-test/suite/optimizer_unfixed_bugs/r/bug43448.result
index a8f56923386..9b7a2c459c3 100644
--- a/mysql-test/suite/optimizer_unfixed_bugs/r/bug43448.result
+++ b/mysql-test/suite/optimizer_unfixed_bugs/r/bug43448.result
@@ -1,6 +1,7 @@
 #
 # Bug#43448 - Server crashes on multi table delete with Innodb
 #
+SET @saved_dbug = @@SESSION.debug_dbug;
 set session debug_dbug="+d,optimizer_innodb_icp";
 CREATE TABLE t1 (
 id1 INT NOT NULL AUTO_INCREMENT PRIMARY KEY, 
@@ -28,3 +29,4 @@ DELETE t1, t2, t3
 FROM t1, t2, t3 
 WHERE t1.id1 = t2.id2 AND t2.id2 = t3.id3 AND t1.id1 > 5;
 DROP TABLE t1, t2, t3;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/optimizer_unfixed_bugs/r/bug43617.result b/mysql-test/suite/optimizer_unfixed_bugs/r/bug43617.result
index 0d88ff3d2cb..11f915aaf8e 100644
--- a/mysql-test/suite/optimizer_unfixed_bugs/r/bug43617.result
+++ b/mysql-test/suite/optimizer_unfixed_bugs/r/bug43617.result
@@ -1,6 +1,7 @@
 set storage_engine=innodb;
 set @save_time_zone= @@time_zone;
 set time_zone='+03:00';
+SET @saved_dbug = @@SESSION.debug_dbug;
 set session debug_dbug="+d,optimizer_innodb_icp";
 CREATE TABLE t1(c1 TIMESTAMP NOT NULL, c2 TIMESTAMP NULL, c3 DATE, c4 DATETIME, PRIMARY KEY(c1), UNIQUE INDEX(c2));
 INSERT INTO t1 VALUES('98-12-31 11:30:45','98.12.31 11+30+45','98-12-31 11:30:45','98.12.31 11+30+45'),('98/12/30 11*30*45','98@12@30 11^30^45','98/12/30 11*30*45','98@12@30 11^30^45'),('98-12-29','98.12.29','98-12-29','98.12.29'),('98/12/28','98@12@28','98/12/28','98@12@28');
@@ -100,3 +101,4 @@ c1	c2	c3	c4
 2038-01-09 03:14:07	2038-01-09 03:14:07	2009-01-05	2009-01-06 00:00:00
 DROP TABLE t1;
 set time_zone= @save_time_zone;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/optimizer_unfixed_bugs/t/bug36981.test b/mysql-test/suite/optimizer_unfixed_bugs/t/bug36981.test
index da9de306b09..5c316c0a4d6 100644
--- a/mysql-test/suite/optimizer_unfixed_bugs/t/bug36981.test
+++ b/mysql-test/suite/optimizer_unfixed_bugs/t/bug36981.test
@@ -4,6 +4,7 @@
 --source include/have_innodb.inc
 
 # crash requires this
+SET @saved_dbug = @@SESSION.debug_dbug;
 set session debug_dbug="+d,optimizer_innodb_icp";
 
 create table `t1` (`c1` char(1) default null,`c2` char(10) default null,
@@ -12,3 +13,4 @@ engine=innodb default charset=latin1;
 insert into `t1` values ('3',null);
 select * from `t1` where `c1`='3' for update;
 drop table `t1`;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/optimizer_unfixed_bugs/t/bug40992.test b/mysql-test/suite/optimizer_unfixed_bugs/t/bug40992.test
index b16f55aa951..41d38445095 100644
--- a/mysql-test/suite/optimizer_unfixed_bugs/t/bug40992.test
+++ b/mysql-test/suite/optimizer_unfixed_bugs/t/bug40992.test
@@ -5,6 +5,7 @@
 --source include/have_debug.inc
 --source include/have_innodb.inc
 
+SET @saved_dbug = @@SESSION.debug_dbug;
 # Crash requires that we enable Index Condition Pushdown in InnoDB
 set session debug_dbug="+d,optimizer_innodb_icp";
 
@@ -19,3 +20,4 @@ INSERT INTO t VALUES (1,1,1),(3,3,3),(5,5,5);
 SELECT * FROM t WHERE a > 2 FOR UPDATE;
 
 DROP TABLE t;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/optimizer_unfixed_bugs/t/bug41996.test b/mysql-test/suite/optimizer_unfixed_bugs/t/bug41996.test
index 7d6237fa536..0eb7e34a9dd 100644
--- a/mysql-test/suite/optimizer_unfixed_bugs/t/bug41996.test
+++ b/mysql-test/suite/optimizer_unfixed_bugs/t/bug41996.test
@@ -5,6 +5,7 @@
 --source include/have_innodb.inc
 
 # crash requires this
+SET @saved_dbug = @@SESSION.debug_dbug;
 set session debug_dbug="+d,optimizer_innodb_icp";
 
 drop table if exists `t1`;
@@ -12,3 +13,4 @@ create table `t1` (`c` bigint, key(`c`),`a` int)engine=innodb;
 insert into `t1` values(2,2);
 delete `t1` from `t1` `a`, `t1` where `a`.`a`=`t1`.`c` ;
 drop table `t1`;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/optimizer_unfixed_bugs/t/bug42991.test b/mysql-test/suite/optimizer_unfixed_bugs/t/bug42991.test
index 2b5864a3e69..d59e9e1fbeb 100644
--- a/mysql-test/suite/optimizer_unfixed_bugs/t/bug42991.test
+++ b/mysql-test/suite/optimizer_unfixed_bugs/t/bug42991.test
@@ -6,6 +6,7 @@
 
 --source include/have_innodb.inc
 
+SET @saved_dbug = @@SESSION.debug_dbug;
 # Valgrind errors happen only with this:
 set session debug_dbug="+d,optimizer_innodb_icp";
 
@@ -246,3 +247,4 @@ UNLOCK TABLES;
 select * from `table5` where  (col2 <= '6566-06-15' AND col24 <> 'd')  group by `col83` order by `col83` desc  ;
 
 drop table `table5`;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/optimizer_unfixed_bugs/t/bug43249.test b/mysql-test/suite/optimizer_unfixed_bugs/t/bug43249.test
index 6275038a650..c647b777059 100644
--- a/mysql-test/suite/optimizer_unfixed_bugs/t/bug43249.test
+++ b/mysql-test/suite/optimizer_unfixed_bugs/t/bug43249.test
@@ -4,6 +4,7 @@
 --source include/have_debug.inc
 --source include/have_innodb.inc
 
+SET @saved_dbug = @@SESSION.debug_dbug;
 set session debug_dbug="+d,optimizer_innodb_icp";
 
 CREATE TABLE t1(c1 TIME NOT NULL, c2 TIME NULL, c3 DATE, PRIMARY
@@ -15,3 +16,4 @@ SELECT * FROM t1 WHERE c2 <=> NULL ORDER BY c2 LIMIT 2;
 SELECT * FROM t1 WHERE c2 <=> NULL ORDER BY c2 LIMIT 2;
 
 drop table `t1`;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/optimizer_unfixed_bugs/t/bug43360.test b/mysql-test/suite/optimizer_unfixed_bugs/t/bug43360.test
index 9bfff0ccdb7..0896caa7712 100644
--- a/mysql-test/suite/optimizer_unfixed_bugs/t/bug43360.test
+++ b/mysql-test/suite/optimizer_unfixed_bugs/t/bug43360.test
@@ -6,6 +6,7 @@
 --source include/have_debug.inc
 --source include/have_innodb.inc
 
+SET @saved_dbug = @@SESSION.debug_dbug;
 # crash requires this
 set session debug_dbug="+d,optimizer_innodb_icp";
 
@@ -42,3 +43,4 @@ SELECT * FROM t1;
 SELECT * FROM t2;
 
 DROP TABLE t1,t2;   
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/optimizer_unfixed_bugs/t/bug43448.test b/mysql-test/suite/optimizer_unfixed_bugs/t/bug43448.test
index f7f40a6d3bf..4e1df63b45b 100644
--- a/mysql-test/suite/optimizer_unfixed_bugs/t/bug43448.test
+++ b/mysql-test/suite/optimizer_unfixed_bugs/t/bug43448.test
@@ -5,6 +5,7 @@
 --source include/have_debug.inc
 --source include/have_innodb.inc
 
+SET @saved_dbug = @@SESSION.debug_dbug;
 # crash requires ICP support in InnoDB
 set session debug_dbug="+d,optimizer_innodb_icp";
 
@@ -58,3 +59,4 @@ FROM t1, t2, t3
 WHERE t1.id1 = t2.id2 AND t2.id2 = t3.id3 AND t1.id1 > 5;
 
 DROP TABLE t1, t2, t3;
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/optimizer_unfixed_bugs/t/bug43617.test b/mysql-test/suite/optimizer_unfixed_bugs/t/bug43617.test
index 2b5b5fd96dd..02d0ab6d566 100644
--- a/mysql-test/suite/optimizer_unfixed_bugs/t/bug43617.test
+++ b/mysql-test/suite/optimizer_unfixed_bugs/t/bug43617.test
@@ -6,6 +6,7 @@
 set storage_engine=innodb;
 set @save_time_zone= @@time_zone;
 set time_zone='+03:00';
+SET @saved_dbug = @@SESSION.debug_dbug;
 set session debug_dbug="+d,optimizer_innodb_icp";
 
 ######## Running INSERT tests for TIMESTAMP ########
@@ -83,4 +84,4 @@ SELECT * FROM t1 WHERE c2 IN ('1971-01-01 00:00:01','2038-01-09 03:14:07') ORDER
 DROP TABLE t1;
 
 set time_zone= @save_time_zone;
-
+SET debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/parts/r/partition_debug.result b/mysql-test/suite/parts/r/partition_debug.result
index 7460fe8dd74..e438cae7a14 100644
--- a/mysql-test/suite/parts/r/partition_debug.result
+++ b/mysql-test/suite/parts/r/partition_debug.result
@@ -6,11 +6,11 @@ CREATE TABLE t1 (a INT, b VARCHAR(64), KEY(b,a))
 PARTITION BY HASH (a) PARTITIONS 3;
 INSERT INTO t1 VALUES (1, "1"), (2, "2"), (3, "3"), (4, "Four"), (5, "Five"),
 (6, "Six"), (7, "Seven"), (8, "Eight"), (9, "Nine");
-SET @save_dbug=@@debug_dbug;
+SET @saved_dbug=@@debug_dbug;
 SET SESSION debug_dbug="+d,ha_partition_fail_index_init";
 SELECT * FROM t1 WHERE b = "Seven";
 ERROR HY000: Table has no partition for value 0
-SET SESSION debug_dbug=@save_dbug;
+SET SESSION debug_dbug=@saved_dbug;
 SELECT * FROM t1 WHERE b = "Seven";
 a	b
 7	Seven
diff --git a/mysql-test/suite/parts/t/partition_debug.test b/mysql-test/suite/parts/t/partition_debug.test
index ef12ee99948..864452f8d8b 100644
--- a/mysql-test/suite/parts/t/partition_debug.test
+++ b/mysql-test/suite/parts/t/partition_debug.test
@@ -18,11 +18,11 @@ CREATE TABLE t1 (a INT, b VARCHAR(64), KEY(b,a))
   PARTITION BY HASH (a) PARTITIONS 3;
   INSERT INTO t1 VALUES (1, "1"), (2, "2"), (3, "3"), (4, "Four"), (5, "Five"),
   (6, "Six"), (7, "Seven"), (8, "Eight"), (9, "Nine");
-SET @save_dbug=@@debug_dbug;
+SET @saved_dbug=@@debug_dbug;
 SET SESSION debug_dbug="+d,ha_partition_fail_index_init";
 --error ER_NO_PARTITION_FOR_GIVEN_VALUE
 SELECT * FROM t1 WHERE b = "Seven";
-SET SESSION debug_dbug=@save_dbug;
+SET SESSION debug_dbug=@saved_dbug;
 SELECT * FROM t1 WHERE b = "Seven";
 DROP TABLE t1;
 
diff --git a/mysql-test/suite/parts/t/partition_debug_innodb.test b/mysql-test/suite/parts/t/partition_debug_innodb.test
index c3fa85ba5ba..0d065d0e3f2 100644
--- a/mysql-test/suite/parts/t/partition_debug_innodb.test
+++ b/mysql-test/suite/parts/t/partition_debug_innodb.test
@@ -30,7 +30,7 @@ INSERT INTO t1 VALUES (6, 'X 6 row'), (7, 'Seventh row'), (8, 'Last row');
 ALTER TABLE t1 ADD INDEX new_b_index (b);
 ALTER TABLE t1 DROP INDEX new_b_index;
 
-SET @save_dbug=@@debug_dbug;
+SET @saved_dbug=@@debug_dbug;
 SET SESSION debug_dbug = "+d,ha_partition_fail_final_add_index";
 
 --error ER_NO_PARTITION_FOR_GIVEN_VALUE
@@ -46,7 +46,7 @@ SHOW CREATE TABLE t1;
 --sorted_result
 SELECT * FROM t1;
 
-SET SESSION debug_dbug = @save_dbug;
+SET SESSION debug_dbug = @saved_dbug;
 SHOW CREATE TABLE t1;
 DROP TABLE t1;
 }
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_again_allow.result b/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_again_allow.result
index 27243b52422..86cab03c4c6 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_again_allow.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_again_allow.result
@@ -22,6 +22,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_error_again";
 connect  con2,"127.0.0.1",root,,test,$MASTER_MYPORT,;
 select "Con2 is alive";
@@ -99,4 +100,4 @@ FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
 revoke select on test.* from 'root'@'192.0.2.4';
 drop user 'root'@'192.0.2.4';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_again_deny.result b/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_again_deny.result
index 7879919b09d..f824c319afa 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_again_deny.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_again_deny.result
@@ -20,6 +20,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_error_again";
 ERROR HY000: Host '192.0.2.4' is not allowed to connect to this MariaDB server
 connection default;
@@ -81,4 +82,4 @@ COUNT_LOCAL_ERRORS	0
 COUNT_UNKNOWN_ERRORS	0
 FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_bad_allow.result b/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_bad_allow.result
index 1d5923483c9..33948013822 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_bad_allow.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_bad_allow.result
@@ -22,6 +22,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_fake_bad_ipv4";
 connect  con2,"127.0.0.1",root,,test,$MASTER_MYPORT,;
 select "Con2 is alive";
@@ -99,4 +100,4 @@ FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
 revoke select on test.* from 'root'@'192.0.2.4';
 drop user 'root'@'192.0.2.4';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_bad_deny.result b/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_bad_deny.result
index 87fc75817df..096c5c3dbd5 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_bad_deny.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_bad_deny.result
@@ -20,6 +20,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_fake_bad_ipv4";
 ERROR HY000: Host '192.0.2.4' is not allowed to connect to this MariaDB server
 connection default;
@@ -81,4 +82,4 @@ COUNT_LOCAL_ERRORS	0
 COUNT_UNKNOWN_ERRORS	0
 FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_good_allow.result b/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_good_allow.result
index 949fa8f9c3e..f36e4604a7c 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_good_allow.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_good_allow.result
@@ -22,6 +22,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_fake_good_ipv4";
 connect  con2,"127.0.0.1",root,,test,$MASTER_MYPORT,;
 select "Con2 is alive";
@@ -99,4 +100,4 @@ FIRST_ERROR_SEEN	null
 LAST_ERROR_SEEN	null
 revoke select on test.* from 'root'@'santa.claus.ipv4.example.com';
 drop user 'root'@'santa.claus.ipv4.example.com';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_good_deny.result b/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_good_deny.result
index b2e0fb60811..d84ffe2e9df 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_good_deny.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_good_deny.result
@@ -20,6 +20,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_fake_good_ipv4";
 ERROR HY000: Host 'santa.claus.ipv4.example.com' is not allowed to connect to this MariaDB server
 connection default;
@@ -81,4 +82,4 @@ COUNT_LOCAL_ERRORS	0
 COUNT_UNKNOWN_ERRORS	0
 FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_noname_allow.result b/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_noname_allow.result
index bfc7fde5be8..ff2a93efec4 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_noname_allow.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_noname_allow.result
@@ -24,6 +24,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_error_noname";
 connect  con2,"127.0.0.1",root,,test,$MASTER_MYPORT,;
 select "Con2 is alive";
@@ -103,4 +104,4 @@ revoke select on test.* from 'root'@'santa.claus.ipv4.example.com';
 revoke select on test.* from 'root'@'192.0.2.4';
 drop user 'root'@'santa.claus.ipv4.example.com';
 drop user 'root'@'192.0.2.4';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_noname_deny.result b/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_noname_deny.result
index 41eb9636e31..c300d6a50af 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_noname_deny.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv4_addrinfo_noname_deny.result
@@ -20,6 +20,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_error_noname";
 ERROR HY000: Host '192.0.2.4' is not allowed to connect to this MariaDB server
 connection default;
@@ -81,4 +82,4 @@ COUNT_LOCAL_ERRORS	0
 COUNT_UNKNOWN_ERRORS	0
 FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv4_auth_plugin.result b/mysql-test/suite/perfschema/r/hostcache_ipv4_auth_plugin.result
index 22dd7e7632c..1c34faa9457 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv4_auth_plugin.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv4_auth_plugin.result
@@ -24,6 +24,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_fake_good_ipv4";
 uninstall plugin test_plugin_server;
 ERROR HY000: Plugin 'test_plugin_server' is not loaded
@@ -194,5 +195,5 @@ REVOKE PROXY ON 'plug_dest'@'santa.claus.ipv4.example.com'
   FROM 'plug'@'santa.claus.ipv4.example.com';
 DROP USER 'plug'@'santa.claus.ipv4.example.com';
 DROP USER 'plug_dest'@'santa.claus.ipv4.example.com';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 delete from mysql.plugin where name='test_plugin_server';
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv4_blocked.result b/mysql-test/suite/perfschema/r/hostcache_ipv4_blocked.result
index f301df94ce6..2751dbd7edb 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv4_blocked.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv4_blocked.result
@@ -25,6 +25,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_fake_good_ipv4,native_password_bad_reply";
 ERROR 08S01: Bad handshake
 connection default;
@@ -427,4 +428,4 @@ drop user 'root'@'santa.claus.ipv4.example.com';
 revoke select on test.* from 'quota'@'santa.claus.ipv4.example.com';
 drop user 'quota'@'santa.claus.ipv4.example.com';
 set global max_connect_errors = @saved_max_connect_errors;
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv4_format.result b/mysql-test/suite/perfschema/r/hostcache_ipv4_format.result
index 14a6ace09e4..18e437559e4 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv4_format.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv4_format.result
@@ -20,6 +20,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_format_ipv4";
 ERROR HY000: Host '192.0.2.4' is not allowed to connect to this MariaDB server
 connection default;
@@ -81,4 +82,4 @@ COUNT_LOCAL_ERRORS	0
 COUNT_UNKNOWN_ERRORS	0
 FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv4_max_con.result b/mysql-test/suite/perfschema/r/hostcache_ipv4_max_con.result
index 6cca75f9775..3d41f013ba9 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv4_max_con.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv4_max_con.result
@@ -25,6 +25,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_fake_good_ipv4";
 connect  con2a,"127.0.0.1",quota,,test,$MASTER_MYPORT,;
 select "Con2a is alive";
@@ -702,4 +703,4 @@ disconnect tmp_con7;
 set global max_connections = @saved_max_connections;
 set global max_user_connections = @saved_max_user_connections;
 drop user 'quota'@'santa.claus.ipv4.example.com';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv4_nameinfo_again_allow.result b/mysql-test/suite/perfschema/r/hostcache_ipv4_nameinfo_again_allow.result
index 6d278da3812..bc7721aef30 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv4_nameinfo_again_allow.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv4_nameinfo_again_allow.result
@@ -24,6 +24,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_error_again";
 connect  con2,"127.0.0.1",root,,test,$MASTER_MYPORT,;
 select "Con2 is alive";
@@ -178,4 +179,4 @@ revoke select on test.* from 'root'@'192.0.2.4';
 revoke select on test.* from 'root'@'santa.claus.ipv4.example.com';
 drop user 'root'@'192.0.2.4';
 drop user 'root'@'santa.claus.ipv4.example.com';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv4_nameinfo_again_deny.result b/mysql-test/suite/perfschema/r/hostcache_ipv4_nameinfo_again_deny.result
index abe9a606bc4..3896ed086ba 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv4_nameinfo_again_deny.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv4_nameinfo_again_deny.result
@@ -20,6 +20,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_error_again";
 ERROR HY000: Host '192.0.2.4' is not allowed to connect to this MariaDB server
 connection default;
@@ -142,4 +143,4 @@ COUNT_LOCAL_ERRORS	0
 COUNT_UNKNOWN_ERRORS	0
 FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv4_nameinfo_noname_allow.result b/mysql-test/suite/perfschema/r/hostcache_ipv4_nameinfo_noname_allow.result
index 18986674491..236bc12d9bf 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv4_nameinfo_noname_allow.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv4_nameinfo_noname_allow.result
@@ -22,6 +22,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_error_noname";
 connect  con2,"127.0.0.1",root,,test,$MASTER_MYPORT,;
 select "Con2 is alive";
@@ -99,4 +100,4 @@ FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
 revoke select on test.* from 'root'@'192.0.2.4';
 drop user 'root'@'192.0.2.4';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv4_nameinfo_noname_deny.result b/mysql-test/suite/perfschema/r/hostcache_ipv4_nameinfo_noname_deny.result
index 88ac817ce17..5479393c29b 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv4_nameinfo_noname_deny.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv4_nameinfo_noname_deny.result
@@ -20,6 +20,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_error_noname";
 ERROR HY000: Host '192.0.2.4' is not allowed to connect to this MariaDB server
 connection default;
@@ -81,4 +82,4 @@ COUNT_LOCAL_ERRORS	0
 COUNT_UNKNOWN_ERRORS	0
 FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv4_passwd.result b/mysql-test/suite/perfschema/r/hostcache_ipv4_passwd.result
index a5f70873ed9..4c2a9d48a63 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv4_passwd.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv4_passwd.result
@@ -24,6 +24,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_fake_good_ipv4";
 ERROR 28000: Access denied for user 'user_without'@'santa.claus.ipv4.example.com' (using password: YES)
 connection default;
@@ -207,4 +208,4 @@ FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
 drop user 'user_with'@'santa.claus.ipv4.example.com';
 drop user 'user_without'@'santa.claus.ipv4.example.com';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv4_ssl.result b/mysql-test/suite/perfschema/r/hostcache_ipv4_ssl.result
index 86e7bf5780b..267f346836d 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv4_ssl.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv4_ssl.result
@@ -28,6 +28,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_fake_good_ipv4";
 ERROR 28000: Access denied for user 'user_ssl'@'santa.claus.ipv4.example.com' (using password: NO)
 connection default;
@@ -151,4 +152,4 @@ FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
 drop user 'user_ssl'@'santa.claus.ipv4.example.com';
 drop user 'user_ssl_x509'@'santa.claus.ipv4.example.com';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_again_allow.result b/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_again_allow.result
index 42d86e858fb..4325cfec6dc 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_again_allow.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_again_allow.result
@@ -22,6 +22,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_error_again";
 connect  con2,"::1",root,,test,$MASTER_MYPORT,;
 select "Con2 is alive";
@@ -99,4 +100,4 @@ FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
 revoke select on test.* from 'root'@'2001:db8::6:6';
 drop user 'root'@'2001:db8::6:6';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_again_deny.result b/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_again_deny.result
index 87e97ba2138..12435dd54f5 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_again_deny.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_again_deny.result
@@ -20,6 +20,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_error_again";
 ERROR HY000: Host '2001:db8::6:6' is not allowed to connect to this MariaDB server
 connection default;
@@ -81,4 +82,4 @@ COUNT_LOCAL_ERRORS	0
 COUNT_UNKNOWN_ERRORS	0
 FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_bad_allow.result b/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_bad_allow.result
index bcd47243d03..57e14dfe913 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_bad_allow.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_bad_allow.result
@@ -22,6 +22,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_fake_bad_ipv6";
 connect  con2,"::1",root,,test,$MASTER_MYPORT,;
 select "Con2 is alive";
@@ -99,4 +100,4 @@ FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
 revoke select on test.* from 'root'@'2001:db8::6:6';
 drop user 'root'@'2001:db8::6:6';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_bad_deny.result b/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_bad_deny.result
index 5c24a86248a..654ed7759b1 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_bad_deny.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_bad_deny.result
@@ -20,6 +20,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_fake_bad_ipv6";
 ERROR HY000: Host '2001:db8::6:6' is not allowed to connect to this MariaDB server
 connection default;
@@ -81,4 +82,4 @@ COUNT_LOCAL_ERRORS	0
 COUNT_UNKNOWN_ERRORS	0
 FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_good_allow.result b/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_good_allow.result
index 68ea9a1d826..f68d90978e7 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_good_allow.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_good_allow.result
@@ -22,6 +22,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_fake_good_ipv6";
 connect  con2,"::1",root,,test,$MASTER_MYPORT,;
 select "Con2 is alive";
@@ -99,4 +100,4 @@ FIRST_ERROR_SEEN	null
 LAST_ERROR_SEEN	null
 revoke select on test.* from 'root'@'santa.claus.ipv6.example.com';
 drop user 'root'@'santa.claus.ipv6.example.com';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_good_deny.result b/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_good_deny.result
index 5b1f546b30e..e63c84bf352 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_good_deny.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_good_deny.result
@@ -19,6 +19,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_fake_good_ipv6";
 ERROR HY000: Host 'santa.claus.ipv6.example.com' is not allowed to connect to this MariaDB server
 connection default;
@@ -80,4 +81,4 @@ COUNT_LOCAL_ERRORS	0
 COUNT_UNKNOWN_ERRORS	0
 FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_noname_allow.result b/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_noname_allow.result
index 0a3a3329c1e..50297797f6a 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_noname_allow.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_noname_allow.result
@@ -24,6 +24,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_error_noname";
 connect  con2,"::1",root,,test,$MASTER_MYPORT,;
 select "Con2 is alive";
@@ -103,4 +104,4 @@ revoke select on test.* from 'root'@'santa.claus.ipv6.example.com';
 revoke select on test.* from 'root'@'2001:db8::6:6';
 drop user 'root'@'santa.claus.ipv6.example.com';
 drop user 'root'@'2001:db8::6:6';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_noname_deny.result b/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_noname_deny.result
index 493ada909b7..549e83369df 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_noname_deny.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv6_addrinfo_noname_deny.result
@@ -20,6 +20,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_error_noname";
 ERROR HY000: Host '2001:db8::6:6' is not allowed to connect to this MariaDB server
 connection default;
@@ -81,4 +82,4 @@ COUNT_LOCAL_ERRORS	0
 COUNT_UNKNOWN_ERRORS	0
 FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv6_auth_plugin.result b/mysql-test/suite/perfschema/r/hostcache_ipv6_auth_plugin.result
index a36d1442ee6..5312958bd91 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv6_auth_plugin.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv6_auth_plugin.result
@@ -24,6 +24,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_fake_good_ipv6";
 uninstall plugin test_plugin_server;
 ERROR HY000: Plugin 'test_plugin_server' is not loaded
@@ -194,5 +195,5 @@ REVOKE PROXY ON 'plug_dest'@'santa.claus.ipv6.example.com'
   FROM 'plug'@'santa.claus.ipv6.example.com';
 DROP USER 'plug'@'santa.claus.ipv6.example.com';
 DROP USER 'plug_dest'@'santa.claus.ipv6.example.com';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 delete from mysql.plugin where name='test_plugin_server';
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv6_blocked.result b/mysql-test/suite/perfschema/r/hostcache_ipv6_blocked.result
index 7cfb6f87277..757285b1033 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv6_blocked.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv6_blocked.result
@@ -25,6 +25,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_fake_good_ipv6,native_password_bad_reply";
 ERROR 08S01: Bad handshake
 connection default;
@@ -427,4 +428,4 @@ drop user 'root'@'santa.claus.ipv6.example.com';
 revoke select on test.* from 'quota'@'santa.claus.ipv6.example.com';
 drop user 'quota'@'santa.claus.ipv6.example.com';
 set global max_connect_errors = @saved_max_connect_errors;
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv6_max_con.result b/mysql-test/suite/perfschema/r/hostcache_ipv6_max_con.result
index f9d2b556804..f2e25ab6ca1 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv6_max_con.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv6_max_con.result
@@ -25,6 +25,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_fake_good_ipv6";
 connect  con2a,"::1",quota,,test,$MASTER_MYPORT,;
 select "Con2a is alive";
@@ -702,4 +703,4 @@ disconnect tmp_con7;
 set global max_connections = @saved_max_connections;
 set global max_user_connections = @saved_max_user_connections;
 drop user 'quota'@'santa.claus.ipv6.example.com';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv6_nameinfo_again_allow.result b/mysql-test/suite/perfschema/r/hostcache_ipv6_nameinfo_again_allow.result
index 6d98c2cc186..357dfd3db3e 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv6_nameinfo_again_allow.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv6_nameinfo_again_allow.result
@@ -24,6 +24,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_error_again";
 connect  con2,"::1",root,,test,$MASTER_MYPORT,;
 select "Con2 is alive";
@@ -178,4 +179,4 @@ revoke select on test.* from 'root'@'2001:db8::6:6';
 revoke select on test.* from 'root'@'santa.claus.ipv6.example.com';
 drop user 'root'@'2001:db8::6:6';
 drop user 'root'@'santa.claus.ipv6.example.com';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv6_nameinfo_again_deny.result b/mysql-test/suite/perfschema/r/hostcache_ipv6_nameinfo_again_deny.result
index 22ce0c3e809..5befbd98087 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv6_nameinfo_again_deny.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv6_nameinfo_again_deny.result
@@ -20,6 +20,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_error_again";
 ERROR HY000: Host '2001:db8::6:6' is not allowed to connect to this MariaDB server
 connection default;
@@ -142,4 +143,4 @@ COUNT_LOCAL_ERRORS	0
 COUNT_UNKNOWN_ERRORS	0
 FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv6_nameinfo_noname_allow.result b/mysql-test/suite/perfschema/r/hostcache_ipv6_nameinfo_noname_allow.result
index a78ba09513c..f899cb935e9 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv6_nameinfo_noname_allow.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv6_nameinfo_noname_allow.result
@@ -22,6 +22,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_error_noname";
 connect  con2,"::1",root,,test,$MASTER_MYPORT,;
 select "Con2 is alive";
@@ -99,4 +100,4 @@ FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
 revoke select on test.* from 'root'@'2001:db8::6:6';
 drop user 'root'@'2001:db8::6:6';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv6_nameinfo_noname_deny.result b/mysql-test/suite/perfschema/r/hostcache_ipv6_nameinfo_noname_deny.result
index da1570f1b37..6d50530ffa0 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv6_nameinfo_noname_deny.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv6_nameinfo_noname_deny.result
@@ -20,6 +20,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_error_noname";
 ERROR HY000: Host '2001:db8::6:6' is not allowed to connect to this MariaDB server
 connection default;
@@ -81,4 +82,4 @@ COUNT_LOCAL_ERRORS	0
 COUNT_UNKNOWN_ERRORS	0
 FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv6_passwd.result b/mysql-test/suite/perfschema/r/hostcache_ipv6_passwd.result
index a4cc3eeb0d0..670a3713d91 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv6_passwd.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv6_passwd.result
@@ -24,6 +24,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_fake_good_ipv6";
 ERROR 28000: Access denied for user 'user_without'@'santa.claus.ipv6.example.com' (using password: YES)
 connection default;
@@ -207,4 +208,4 @@ FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
 drop user 'user_with'@'santa.claus.ipv6.example.com';
 drop user 'user_without'@'santa.claus.ipv6.example.com';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_ipv6_ssl.result b/mysql-test/suite/perfschema/r/hostcache_ipv6_ssl.result
index 75f8e5391cf..9ec33df2fee 100644
--- a/mysql-test/suite/perfschema/r/hostcache_ipv6_ssl.result
+++ b/mysql-test/suite/perfschema/r/hostcache_ipv6_ssl.result
@@ -28,6 +28,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_fake_good_ipv6";
 ERROR 28000: Access denied for user 'user_ssl'@'santa.claus.ipv6.example.com' (using password: NO)
 connection default;
@@ -151,4 +152,4 @@ FIRST_ERROR_SEEN	set
 LAST_ERROR_SEEN	set
 drop user 'user_ssl'@'santa.claus.ipv6.example.com';
 drop user 'user_ssl_x509'@'santa.claus.ipv6.example.com';
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/r/hostcache_peer_addr.result b/mysql-test/suite/perfschema/r/hostcache_peer_addr.result
index ddb44157f44..6d15f2f5b25 100644
--- a/mysql-test/suite/perfschema/r/hostcache_peer_addr.result
+++ b/mysql-test/suite/perfschema/r/hostcache_peer_addr.result
@@ -27,6 +27,7 @@ current_user()
 root@localhost
 disconnect con1;
 connection default;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_error";
 ERROR HY000: Can't get hostname for your address
 connection default;
@@ -50,7 +51,7 @@ Connection_errors_peer_address	2
 Connection_errors_select	0
 Connection_errors_tcpwrap	0
 "Dumping performance_schema.host_cache"
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 flush status;
 show global status like "connection_errors_%";
 Variable_name	Value
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_again_allow.test b/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_again_allow.test
index 6bed01e50bf..c96c8ea37c8 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_again_allow.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_again_allow.test
@@ -27,6 +27,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_error_again";
 
 connect (con2,"127.0.0.1",root,,test,$MASTER_MYPORT,);
@@ -48,5 +49,5 @@ disconnect con3;
 revoke select on test.* from 'root'@'192.0.2.4';
 drop user 'root'@'192.0.2.4';
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_again_deny.test b/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_again_deny.test
index 3c72de8a05e..00f5d218e17 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_again_deny.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_again_deny.test
@@ -25,6 +25,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_error_again";
 
 --disable_query_log
@@ -43,5 +44,5 @@ connect (con3,"127.0.0.1",root,,test,$MASTER_MYPORT,);
 --connection default
 --source ../include/hostcache_dump.inc
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_bad_allow.test b/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_bad_allow.test
index 5cbe4c30530..d2dff92834e 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_bad_allow.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_bad_allow.test
@@ -30,6 +30,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_fake_bad_ipv4";
 
 connect (con2,"127.0.0.1",root,,test,$MASTER_MYPORT,);
@@ -51,5 +52,5 @@ disconnect con3;
 revoke select on test.* from 'root'@'192.0.2.4';
 drop user 'root'@'192.0.2.4';
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_bad_deny.test b/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_bad_deny.test
index c0639cd6b86..f37e1ed3b90 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_bad_deny.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_bad_deny.test
@@ -27,6 +27,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_fake_bad_ipv4";
 
 --disable_query_log
@@ -45,5 +46,5 @@ connect (con3,"127.0.0.1",root,,test,$MASTER_MYPORT,);
 --connection default
 --source ../include/hostcache_dump.inc
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_good_allow.test b/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_good_allow.test
index 3b69e0731a0..d2b5352d3a6 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_good_allow.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_good_allow.test
@@ -28,6 +28,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_fake_good_ipv4";
 
 connect (con2,"127.0.0.1",root,,test,$MASTER_MYPORT,);
@@ -49,5 +50,5 @@ disconnect con3;
 revoke select on test.* from 'root'@'santa.claus.ipv4.example.com';
 drop user 'root'@'santa.claus.ipv4.example.com';
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_good_deny.test b/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_good_deny.test
index e6478c13951..55afb6f0c4f 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_good_deny.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_good_deny.test
@@ -25,6 +25,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_fake_good_ipv4";
 
 --disable_query_log
@@ -43,5 +44,5 @@ connect (con3,"127.0.0.1",root,,test,$MASTER_MYPORT,);
 --connection default
 --source ../include/hostcache_dump.inc
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_noname_allow.test b/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_noname_allow.test
index b4b11526af6..a6bd4c751e2 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_noname_allow.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_noname_allow.test
@@ -30,6 +30,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_error_noname";
 
 connect (con2,"127.0.0.1",root,,test,$MASTER_MYPORT,);
@@ -53,5 +54,5 @@ revoke select on test.* from 'root'@'192.0.2.4';
 drop user 'root'@'santa.claus.ipv4.example.com';
 drop user 'root'@'192.0.2.4';
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_noname_deny.test b/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_noname_deny.test
index 06f0f7d29ee..41b8b25efc4 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_noname_deny.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv4_addrinfo_noname_deny.test
@@ -25,6 +25,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_error_noname";
 
 --disable_query_log
@@ -43,5 +44,5 @@ connect (con3,"127.0.0.1",root,,test,$MASTER_MYPORT,);
 --connection default
 --source ../include/hostcache_dump.inc
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv4_auth_plugin.test b/mysql-test/suite/perfschema/t/hostcache_ipv4_auth_plugin.test
index 325460e66ba..6e149b838ef 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv4_auth_plugin.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv4_auth_plugin.test
@@ -30,6 +30,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_fake_good_ipv4";
 uninstall plugin test_plugin_server;
 
@@ -86,6 +87,6 @@ REVOKE PROXY ON 'plug_dest'@'santa.claus.ipv4.example.com'
 DROP USER 'plug'@'santa.claus.ipv4.example.com';
 DROP USER 'plug_dest'@'santa.claus.ipv4.example.com';
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 delete from mysql.plugin where name='test_plugin_server';
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv4_blocked.test b/mysql-test/suite/perfschema/t/hostcache_ipv4_blocked.test
index 6990a4e7118..d304cc5a1b8 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv4_blocked.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv4_blocked.test
@@ -33,6 +33,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_fake_good_ipv4,native_password_bad_reply";
 
 --disable_query_log
@@ -156,5 +157,5 @@ revoke select on test.* from 'quota'@'santa.claus.ipv4.example.com';
 drop user 'quota'@'santa.claus.ipv4.example.com';
 
 set global max_connect_errors = @saved_max_connect_errors;
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv4_format.test b/mysql-test/suite/perfschema/t/hostcache_ipv4_format.test
index b37bfc79ada..989c82ef0ad 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv4_format.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv4_format.test
@@ -24,6 +24,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_format_ipv4";
 
 --disable_query_log
@@ -42,5 +43,5 @@ connect (con3,"127.0.0.1",root,,test,$MASTER_MYPORT,);
 --connection default
 --source ../include/hostcache_dump.inc
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv4_max_con.test b/mysql-test/suite/perfschema/t/hostcache_ipv4_max_con.test
index c0349184506..6420b8b5300 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv4_max_con.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv4_max_con.test
@@ -31,6 +31,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_fake_good_ipv4";
 
 connect (con2a,"127.0.0.1",quota,,test,$MASTER_MYPORT,);
@@ -259,5 +260,5 @@ set global max_user_connections = @saved_max_user_connections;
 # revoke all privileges on test.* from 'quota'@'santa.claus.ipv4.example.com';
 drop user 'quota'@'santa.claus.ipv4.example.com';
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv4_nameinfo_again_allow.test b/mysql-test/suite/perfschema/t/hostcache_ipv4_nameinfo_again_allow.test
index 187879985c9..5a2caf5849e 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv4_nameinfo_again_allow.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv4_nameinfo_again_allow.test
@@ -30,6 +30,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_error_again";
 
 connect (con2,"127.0.0.1",root,,test,$MASTER_MYPORT,);
@@ -71,5 +72,5 @@ revoke select on test.* from 'root'@'santa.claus.ipv4.example.com';
 drop user 'root'@'192.0.2.4';
 drop user 'root'@'santa.claus.ipv4.example.com';
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv4_nameinfo_again_deny.test b/mysql-test/suite/perfschema/t/hostcache_ipv4_nameinfo_again_deny.test
index a78c0dab4eb..6cd2664a04f 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv4_nameinfo_again_deny.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv4_nameinfo_again_deny.test
@@ -25,6 +25,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_error_again";
 
 --disable_query_log
@@ -61,5 +62,5 @@ connect (con5,"127.0.0.1",root,,test,$MASTER_MYPORT,);
 --connection default
 --source ../include/hostcache_dump.inc
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv4_nameinfo_noname_allow.test b/mysql-test/suite/perfschema/t/hostcache_ipv4_nameinfo_noname_allow.test
index 23ecd51eb4f..19a3ebe9892 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv4_nameinfo_noname_allow.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv4_nameinfo_noname_allow.test
@@ -28,6 +28,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_error_noname";
 
 connect (con2,"127.0.0.1",root,,test,$MASTER_MYPORT,);
@@ -49,5 +50,5 @@ disconnect con3;
 revoke select on test.* from 'root'@'192.0.2.4';
 drop user 'root'@'192.0.2.4';
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv4_nameinfo_noname_deny.test b/mysql-test/suite/perfschema/t/hostcache_ipv4_nameinfo_noname_deny.test
index 4b6c91c3df3..28e5615d273 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv4_nameinfo_noname_deny.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv4_nameinfo_noname_deny.test
@@ -25,6 +25,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_error_noname";
 
 --disable_query_log
@@ -43,5 +44,5 @@ connect (con3,"127.0.0.1",root,,test,$MASTER_MYPORT,);
 --connection default
 --source ../include/hostcache_dump.inc
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv4_passwd.test b/mysql-test/suite/perfschema/t/hostcache_ipv4_passwd.test
index ea331647b48..c6ff89f0902 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv4_passwd.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv4_passwd.test
@@ -29,6 +29,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_fake_good_ipv4";
 
 --disable_query_log
@@ -82,5 +83,5 @@ connect (con2f,"127.0.0.1",user_with,wrong_password,test,$MASTER_MYPORT,);
 drop user 'user_with'@'santa.claus.ipv4.example.com';
 drop user 'user_without'@'santa.claus.ipv4.example.com';
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv4_ssl.test b/mysql-test/suite/perfschema/t/hostcache_ipv4_ssl.test
index 2b949098bad..bd8d48984e4 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv4_ssl.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv4_ssl.test
@@ -30,6 +30,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_fake_good_ipv4";
 
 --disable_query_log
@@ -67,5 +68,5 @@ connect (con2d,"127.0.0.1",user_ssl_x509,good_password,test,$MASTER_MYPORT,,SSL)
 drop user 'user_ssl'@'santa.claus.ipv4.example.com';
 drop user 'user_ssl_x509'@'santa.claus.ipv4.example.com';
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_again_allow.test b/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_again_allow.test
index 11c45724f70..100fdffa377 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_again_allow.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_again_allow.test
@@ -29,6 +29,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_error_again";
 
 connect (con2,"::1",root,,test,$MASTER_MYPORT,);
@@ -50,5 +51,5 @@ disconnect con3;
 revoke select on test.* from 'root'@'2001:db8::6:6';
 drop user 'root'@'2001:db8::6:6';
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_again_deny.test b/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_again_deny.test
index bdbc0e3c025..8aafff745c4 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_again_deny.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_again_deny.test
@@ -26,6 +26,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_error_again";
 
 --disable_query_log
@@ -44,5 +45,5 @@ connect (con3,"::1",root,,test,$MASTER_MYPORT,);
 --connection default
 --source ../include/hostcache_dump.inc
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_bad_allow.test b/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_bad_allow.test
index 1eb0d3ec41f..eaf46a5c57e 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_bad_allow.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_bad_allow.test
@@ -31,6 +31,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_fake_bad_ipv6";
 
 connect (con2,"::1",root,,test,$MASTER_MYPORT,);
@@ -52,5 +53,5 @@ disconnect con3;
 revoke select on test.* from 'root'@'2001:db8::6:6';
 drop user 'root'@'2001:db8::6:6';
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_bad_deny.test b/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_bad_deny.test
index f8a3cc23c00..6c4ede9da8e 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_bad_deny.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_bad_deny.test
@@ -28,6 +28,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_fake_bad_ipv6";
 
 --disable_query_log
@@ -46,5 +47,5 @@ connect (con3,"::1",root,,test,$MASTER_MYPORT,);
 --connection default
 --source ../include/hostcache_dump.inc
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_good_allow.test b/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_good_allow.test
index 6493bb61a1a..e290a5f8ab4 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_good_allow.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_good_allow.test
@@ -29,6 +29,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_fake_good_ipv6";
 
 connect (con2,"::1",root,,test,$MASTER_MYPORT,);
@@ -50,5 +51,5 @@ disconnect con3;
 revoke select on test.* from 'root'@'santa.claus.ipv6.example.com';
 drop user 'root'@'santa.claus.ipv6.example.com';
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_good_deny.test b/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_good_deny.test
index 065ae02dd49..4feb0ffb7c8 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_good_deny.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_good_deny.test
@@ -22,6 +22,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_fake_good_ipv6";
 
 --disable_query_log
@@ -40,5 +41,5 @@ connect (con3,"::1",root,,test,$MASTER_MYPORT,);
 --connection default
 --source ../include/hostcache_dump.inc
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_noname_allow.test b/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_noname_allow.test
index 9ebafc9627d..6b422a19dbd 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_noname_allow.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_noname_allow.test
@@ -31,6 +31,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_error_noname";
 
 connect (con2,"::1",root,,test,$MASTER_MYPORT,);
@@ -54,5 +55,4 @@ revoke select on test.* from 'root'@'2001:db8::6:6';
 drop user 'root'@'santa.claus.ipv6.example.com';
 drop user 'root'@'2001:db8::6:6';
 
-set global debug_dbug= default;
-
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_noname_deny.test b/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_noname_deny.test
index 136b3c7a24f..c81b799edd1 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_noname_deny.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv6_addrinfo_noname_deny.test
@@ -26,6 +26,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_error_noname";
 
 --disable_query_log
@@ -44,5 +45,4 @@ connect (con3,"::1",root,,test,$MASTER_MYPORT,);
 --connection default
 --source ../include/hostcache_dump.inc
 
-set global debug_dbug= default;
-
+SET @@GLOBAL.debug_dbug = @saved_dbug;
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv6_auth_plugin.test b/mysql-test/suite/perfschema/t/hostcache_ipv6_auth_plugin.test
index 3a822bfacb3..d2e4ed69d79 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv6_auth_plugin.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv6_auth_plugin.test
@@ -31,6 +31,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_fake_good_ipv6";
 uninstall plugin test_plugin_server;
 
@@ -87,6 +88,6 @@ REVOKE PROXY ON 'plug_dest'@'santa.claus.ipv6.example.com'
 DROP USER 'plug'@'santa.claus.ipv6.example.com';
 DROP USER 'plug_dest'@'santa.claus.ipv6.example.com';
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 delete from mysql.plugin where name='test_plugin_server';
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv6_blocked.test b/mysql-test/suite/perfschema/t/hostcache_ipv6_blocked.test
index 0a04ec306cf..6da99e02444 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv6_blocked.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv6_blocked.test
@@ -33,6 +33,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_fake_good_ipv6,native_password_bad_reply";
 
 --disable_query_log
@@ -156,5 +157,5 @@ revoke select on test.* from 'quota'@'santa.claus.ipv6.example.com';
 drop user 'quota'@'santa.claus.ipv6.example.com';
 
 set global max_connect_errors = @saved_max_connect_errors;
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv6_max_con.test b/mysql-test/suite/perfschema/t/hostcache_ipv6_max_con.test
index b14fff1cc72..6f83221c496 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv6_max_con.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv6_max_con.test
@@ -32,6 +32,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_fake_good_ipv6";
 
 connect (con2a,"::1",quota,,test,$MASTER_MYPORT,);
@@ -241,5 +242,5 @@ set global max_user_connections = @saved_max_user_connections;
 # revoke all privileges on test.* from 'quota'@'santa.claus.ipv6.example.com';
 drop user 'quota'@'santa.claus.ipv6.example.com';
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv6_nameinfo_again_allow.test b/mysql-test/suite/perfschema/t/hostcache_ipv6_nameinfo_again_allow.test
index b44b58eb0d5..896b9bb4886 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv6_nameinfo_again_allow.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv6_nameinfo_again_allow.test
@@ -31,6 +31,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_error_again";
 
 connect (con2,"::1",root,,test,$MASTER_MYPORT,);
@@ -72,5 +73,5 @@ revoke select on test.* from 'root'@'santa.claus.ipv6.example.com';
 drop user 'root'@'2001:db8::6:6';
 drop user 'root'@'santa.claus.ipv6.example.com';
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv6_nameinfo_again_deny.test b/mysql-test/suite/perfschema/t/hostcache_ipv6_nameinfo_again_deny.test
index 073451c7e75..17cc1ffa528 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv6_nameinfo_again_deny.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv6_nameinfo_again_deny.test
@@ -26,6 +26,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_error_again";
 
 --disable_query_log
@@ -62,5 +63,5 @@ connect (con5,"::1",root,,test,$MASTER_MYPORT,);
 --connection default
 --source ../include/hostcache_dump.inc
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv6_nameinfo_noname_allow.test b/mysql-test/suite/perfschema/t/hostcache_ipv6_nameinfo_noname_allow.test
index a7b1a961f09..8e31420b6f1 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv6_nameinfo_noname_allow.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv6_nameinfo_noname_allow.test
@@ -29,6 +29,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_error_noname";
 
 connect (con2,"::1",root,,test,$MASTER_MYPORT,);
@@ -50,5 +51,5 @@ disconnect con3;
 revoke select on test.* from 'root'@'2001:db8::6:6';
 drop user 'root'@'2001:db8::6:6';
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv6_nameinfo_noname_deny.test b/mysql-test/suite/perfschema/t/hostcache_ipv6_nameinfo_noname_deny.test
index 5c3d643b166..ddffc820a2b 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv6_nameinfo_noname_deny.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv6_nameinfo_noname_deny.test
@@ -26,6 +26,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_error_noname";
 
 --disable_query_log
@@ -44,5 +45,5 @@ connect (con3,"::1",root,,test,$MASTER_MYPORT,);
 --connection default
 --source ../include/hostcache_dump.inc
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv6_passwd.test b/mysql-test/suite/perfschema/t/hostcache_ipv6_passwd.test
index 7dcfbb922e5..7281a8b36ec 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv6_passwd.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv6_passwd.test
@@ -27,6 +27,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_fake_good_ipv6";
 
 --disable_query_log
@@ -80,5 +81,5 @@ connect (con2f,"::1",user_with,wrong_password,test,$MASTER_MYPORT,);
 drop user 'user_with'@'santa.claus.ipv6.example.com';
 drop user 'user_without'@'santa.claus.ipv6.example.com';
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_ipv6_ssl.test b/mysql-test/suite/perfschema/t/hostcache_ipv6_ssl.test
index 3ea4451c7aa..d822d9f9bed 100644
--- a/mysql-test/suite/perfschema/t/hostcache_ipv6_ssl.test
+++ b/mysql-test/suite/perfschema/t/hostcache_ipv6_ssl.test
@@ -31,6 +31,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_fake_ipv6,getnameinfo_fake_ipv6,getaddrinfo_fake_good_ipv6";
 
 --disable_query_log
@@ -68,5 +69,5 @@ connect (con2d,"::1",user_ssl_x509,good_password,test,$MASTER_MYPORT,,SSL);
 drop user 'user_ssl'@'santa.claus.ipv6.example.com';
 drop user 'user_ssl_x509'@'santa.claus.ipv6.example.com';
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
diff --git a/mysql-test/suite/perfschema/t/hostcache_peer_addr.test b/mysql-test/suite/perfschema/t/hostcache_peer_addr.test
index 65f33ce73a8..827421312dc 100644
--- a/mysql-test/suite/perfschema/t/hostcache_peer_addr.test
+++ b/mysql-test/suite/perfschema/t/hostcache_peer_addr.test
@@ -22,6 +22,7 @@ select current_user();
 disconnect con1;
 
 --connection default
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= "+d,vio_peer_addr_error";
 
 --disable_query_log
@@ -42,7 +43,7 @@ connect (con3,"127.0.0.1",root,,test,$MASTER_MYPORT,);
 show global status like "connection_errors_%";
 --source ../include/hostcache_dump.inc
 
-set global debug_dbug= default;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
 flush status;
 show global status like "connection_errors_%";
diff --git a/mysql-test/suite/rpl/include/rpl_checksum.inc b/mysql-test/suite/rpl/include/rpl_checksum.inc
index b5e70abe4d0..17a986dc308 100644
--- a/mysql-test/suite/rpl/include/rpl_checksum.inc
+++ b/mysql-test/suite/rpl/include/rpl_checksum.inc
@@ -108,6 +108,7 @@ insert into t1 values (1) /* will not be applied on slave due to simulation */;
 # instruction to the dump thread
 
 connection slave;
+set @saved_dbug = @@global.debug_dbug;
 set @@global.debug_dbug='d,simulate_slave_unaware_checksum';
 start slave;
 --let $slave_io_errno= 1236
@@ -116,8 +117,7 @@ source include/wait_for_slave_io_error.inc;
 
 select count(*) as zero from t1;
 
-###connection master;
-set @@global.debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
 
 connection slave;
 source include/start_slave.inc;
@@ -129,10 +129,11 @@ source include/start_slave.inc;
 # C1. Failure by a client thread
 connection master;
 set @@global.master_verify_checksum = 1;
+set @save_dbug = @@session.debug_dbug;
 set @@session.debug_dbug='d,simulate_checksum_test_failure';
 --error ER_ERROR_WHEN_EXECUTING_COMMAND
 show binlog events;
-set @@session.debug_dbug='';
+SET debug_dbug= @save_dbug;
 set @@global.master_verify_checksum = default;
 
 #connection master;
@@ -149,6 +150,7 @@ connection slave;
 
 # C2. Failure by IO thread
 # instruction to io thread
+set @saved_dbug = @@global.debug_dbug;
 set @@global.debug_dbug='d,simulate_checksum_test_failure';
 start slave io_thread;
 # When the checksum error is detected, the slave sets error code 1913
@@ -158,7 +160,7 @@ start slave io_thread;
 --let $slave_io_errno= 1595,1913
 --let $show_slave_io_error= 0
 source include/wait_for_slave_io_error.inc;
-set @@global.debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
 
 # to make IO thread re-read it again w/o the failure
 start slave io_thread;
@@ -179,7 +181,7 @@ source include/wait_for_slave_sql_error.inc;
 
 # resuming SQL thread to parse out the event w/o the failure
 
-set @@global.debug_dbug=''; 
+set @@global.debug_dbug = @saved_dbug;
 source include/start_slave.inc;
 
 connection master;
diff --git a/mysql-test/suite/rpl/include/rpl_corruption.inc b/mysql-test/suite/rpl/include/rpl_corruption.inc
index 1726ee4ba2f..88f683ed53d 100644
--- a/mysql-test/suite/rpl/include/rpl_corruption.inc
+++ b/mysql-test/suite/rpl/include/rpl_corruption.inc
@@ -73,6 +73,7 @@ while ($i) {
 
 # Emulate corruption in binlog file when SHOW BINLOG EVENTS is executing
 --echo # 2. Corruption in master binlog and SHOW BINLOG EVENTS
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug="+d,corrupt_read_log_event_char";
 --echo SHOW BINLOG EVENTS;
 --disable_query_log
@@ -167,10 +168,10 @@ let $diff_tables= master:test.t1, slave:test.t1;
 # Clean up
 --echo # 8. Clean up
 --connection master
-SET GLOBAL debug_dbug= "";
+set @@global.debug_dbug = @saved_dbug;
 SET GLOBAL master_verify_checksum = @old_master_verify_checksum;
 DROP TABLE t1;
 --sync_slave_with_master
-SET GLOBAL debug_dbug= "";
+set @@global.debug_dbug = @saved_dbug;
 
 --source include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/include/rpl_incident.inc b/mysql-test/suite/rpl/include/rpl_incident.inc
index 350a2086681..75d28d6a6c6 100644
--- a/mysql-test/suite/rpl/include/rpl_incident.inc
+++ b/mysql-test/suite/rpl/include/rpl_incident.inc
@@ -20,7 +20,7 @@ CREATE TABLE t1 (a INT);
 INSERT INTO t1 VALUES (1),(2),(3);
 SELECT * FROM t1;
 
-let $debug_save= `SELECT @@GLOBAL.debug`;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug= '+d,incident_database_resync_on_replace,*';
 
 # This will generate an incident log event and store it in the binary
@@ -29,9 +29,7 @@ REPLACE INTO t1 VALUES (4);
 --save_master_pos
 SELECT * FROM t1;
 
---disable_query_log
-eval SET GLOBAL debug_dbug= '$debug_save';
---enable_query_log
+set @@global.debug_dbug = @saved_dbug;
 
 connection slave;
 # Wait until SQL thread stops with error LOST_EVENT on master
diff --git a/mysql-test/suite/rpl/include/rpl_init_slave_errors.inc b/mysql-test/suite/rpl/include/rpl_init_slave_errors.inc
index 4fdea651edd..46673ea4764 100644
--- a/mysql-test/suite/rpl/include/rpl_init_slave_errors.inc
+++ b/mysql-test/suite/rpl/include/rpl_init_slave_errors.inc
@@ -51,6 +51,7 @@ reset slave;
 connection slave;
 
 # Set debug flags on slave to force errors to occur
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug= "d,simulate_io_slave_error_on_init,simulate_sql_slave_error_on_init";
 
 start slave;
@@ -66,7 +67,7 @@ start slave;
 
 call mtr.add_suppression("Failed during slave.* thread initialization");
 
-SET GLOBAL debug_dbug= "";
+set @@global.debug_dbug = @saved_dbug;
 
 ######################################################################
 #             Injecting faults in the init_slave option
diff --git a/mysql-test/suite/rpl/r/kill_race_condition.result b/mysql-test/suite/rpl/r/kill_race_condition.result
index 1181eb0b0b1..8e8645cdb58 100644
--- a/mysql-test/suite/rpl/r/kill_race_condition.result
+++ b/mysql-test/suite/rpl/r/kill_race_condition.result
@@ -4,6 +4,7 @@ connection master;
 create table t1 (a int);
 connection slave;
 connection slave;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug='d,rows_log_event_before_open_table';
 connection master;
 insert t1 values (1),(2),(3);
@@ -13,7 +14,7 @@ kill slave_sql_thread;
 set debug_sync='now SIGNAL go_ahead_sql';
 include/wait_for_slave_sql_error.inc [errno=1927]
 Last_SQL_Error = Error executing row event: 'Connection was killed'
-set global debug_dbug='';
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 set debug_sync='RESET';
 connection master;
 drop table t1;
diff --git a/mysql-test/suite/rpl/r/rpl_binlog_rollback_cleanup.result b/mysql-test/suite/rpl/r/rpl_binlog_rollback_cleanup.result
new file mode 100644
index 00000000000..a677cbfecf6
--- /dev/null
+++ b/mysql-test/suite/rpl/r/rpl_binlog_rollback_cleanup.result
@@ -0,0 +1,9 @@
+include/master-slave.inc
+[connection master]
+connection master;
+SET GLOBAL max_binlog_cache_size = 65536;
+CREATE TABLE t1(a INT PRIMARY KEY, data VARCHAR(30000)) ENGINE=INNODB;
+ERROR HY000: Multi-statement transaction required more than 'max_binlog_cache_size' bytes of storage; increase this mysqld variable and try again
+SET GLOBAL max_binlog_cache_size= ORIGINAL_VALUE;
+DROP TABLE t1;
+include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/r/rpl_bug33931.result b/mysql-test/suite/rpl/r/rpl_bug33931.result
index 74ba945b027..bdf2c707e9b 100644
--- a/mysql-test/suite/rpl/r/rpl_bug33931.result
+++ b/mysql-test/suite/rpl/r/rpl_bug33931.result
@@ -5,10 +5,11 @@ call mtr.add_suppression("Failed during slave I/O thread initialization");
 call mtr.add_suppression("Slave SQL.*Failed during slave thread initialization.* 1593");
 include/stop_slave.inc
 reset slave;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 SET GLOBAL debug_dbug="d,simulate_io_slave_error_on_init,simulate_sql_slave_error_on_init";
 start slave;
 include/wait_for_slave_sql_error.inc [errno=1593]
 Last_SQL_Error = 'Failed during slave thread initialization'
-SET GLOBAL debug_dbug="";
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 RESET SLAVE;
 include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/r/rpl_bug41902.result b/mysql-test/suite/rpl/r/rpl_bug41902.result
index 8667795bd77..7d676ea73e3 100644
--- a/mysql-test/suite/rpl/r/rpl_bug41902.result
+++ b/mysql-test/suite/rpl/r/rpl_bug41902.result
@@ -2,6 +2,7 @@ include/master-slave.inc
 [connection master]
 connection slave;
 stop slave;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 SET @@debug_dbug="d,simulate_find_log_pos_error";
 reset slave;
 ERROR HY000: Target log not found in binlog index
@@ -19,6 +20,7 @@ SET @@debug_dbug="";
 reset slave;
 change master to master_host='dummy';
 connection master;
+SET @saved_dbug_m = @@global.debug_dbug;
 SET @@debug_dbug="d,simulate_find_log_pos_error";
 reset master;
 ERROR HY000: Target log not found in binlog index
@@ -29,6 +31,7 @@ purge binary logs to 'master-bin.000001';
 ERROR HY000: Target log not found in binlog index
 SET @@debug_dbug="";
 purge binary logs to 'master-bin.000001';
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 ==== clean up ====
 CHANGE MASTER TO MASTER_HOST = '127.0.0.1';
 include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/r/rpl_checksum.result b/mysql-test/suite/rpl/r/rpl_checksum.result
index a74b688d722..21d8ca22feb 100644
--- a/mysql-test/suite/rpl/r/rpl_checksum.result
+++ b/mysql-test/suite/rpl/r/rpl_checksum.result
@@ -76,6 +76,7 @@ connection master;
 set @@global.binlog_checksum = CRC32;
 insert into t1 values (1) /* will not be applied on slave due to simulation */;
 connection slave;
+set @saved_dbug = @@global.debug_dbug;
 set @@global.debug_dbug='d,simulate_slave_unaware_checksum';
 start slave;
 include/wait_for_slave_io_error.inc [errno=1236]
@@ -83,15 +84,16 @@ Last_IO_Error = 'Got fatal error 1236 from master when reading data from binary
 select count(*) as zero from t1;
 zero
 0
-set @@global.debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
 connection slave;
 include/start_slave.inc
 connection master;
 set @@global.master_verify_checksum = 1;
+set @save_dbug = @@session.debug_dbug;
 set @@session.debug_dbug='d,simulate_checksum_test_failure';
 show binlog events;
 ERROR HY000: Error when executing command SHOW BINLOG EVENTS: Wrong offset or I/O error
-set @@session.debug_dbug='';
+SET debug_dbug= @save_dbug;
 set @@global.master_verify_checksum = default;
 connection slave;
 connection slave;
@@ -99,10 +101,11 @@ include/stop_slave.inc
 connection master;
 create table t2 (a int);
 connection slave;
+set @saved_dbug = @@global.debug_dbug;
 set @@global.debug_dbug='d,simulate_checksum_test_failure';
 start slave io_thread;
 include/wait_for_slave_io_error.inc [errno=1595,1913]
-set @@global.debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
 start slave io_thread;
 include/wait_for_slave_param.inc [Read_Master_Log_Pos]
 set @@global.slave_sql_verify_checksum = 1;
@@ -110,7 +113,7 @@ set @@global.debug_dbug='d,simulate_checksum_test_failure';
 start slave sql_thread;
 include/wait_for_slave_sql_error.inc [errno=1593]
 Last_SQL_Error = 'Error initializing relay log position: I/O error reading event at position 4'
-set @@global.debug_dbug='';
+set @@global.debug_dbug = @saved_dbug;
 include/start_slave.inc
 connection master;
 connection slave;
diff --git a/mysql-test/suite/rpl/r/rpl_corruption.result b/mysql-test/suite/rpl/r/rpl_corruption.result
index 25a82fd60cd..db72bb304fc 100644
--- a/mysql-test/suite/rpl/r/rpl_corruption.result
+++ b/mysql-test/suite/rpl/r/rpl_corruption.result
@@ -13,6 +13,7 @@ connection master;
 CREATE TABLE t1 (a INT NOT NULL PRIMARY KEY, b VARCHAR(10), c VARCHAR(100));
 include/stop_slave.inc
 # 2. Corruption in master binlog and SHOW BINLOG EVENTS
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug="+d,corrupt_read_log_event_char";
 SHOW BINLOG EVENTS;
 ERROR HY000: Error when executing command SHOW BINLOG EVENTS: Wrong offset or I/O error
@@ -55,9 +56,9 @@ connection slave;
 include/diff_tables.inc [master:test.t1, slave:test.t1]
 # 8. Clean up
 connection master;
-SET GLOBAL debug_dbug= "";
+set @@global.debug_dbug = @saved_dbug;
 SET GLOBAL master_verify_checksum = @old_master_verify_checksum;
 DROP TABLE t1;
 connection slave;
-SET GLOBAL debug_dbug= "";
+set @@global.debug_dbug = @saved_dbug;
 include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/r/rpl_heartbeat_debug.result b/mysql-test/suite/rpl/r/rpl_heartbeat_debug.result
index cf26c3bf04a..dc45c0b9ab3 100644
--- a/mysql-test/suite/rpl/r/rpl_heartbeat_debug.result
+++ b/mysql-test/suite/rpl/r/rpl_heartbeat_debug.result
@@ -7,7 +7,7 @@ set @@global.slave_net_timeout= 10;
 show status like 'Slave_heartbeat_period';;
 Variable_name	Slave_heartbeat_period
 Value	60.000
-SET @save_dbug= @@GLOBAL.debug_dbug;
+SET @saved_dbug= @@GLOBAL.debug_dbug;
 SET GLOBAL debug_dbug="+d,simulate_slave_heartbeat_network_error";
 CALL mtr.add_suppression('SET @master_heartbeat_period to master failed with error');
 CALL mtr.add_suppression('Master command COM_REGISTER_SLAVE failed: failed registering on master, reconnecting to try again');
@@ -25,7 +25,7 @@ connection master;
 drop table t1;
 connection slave;
 include/stop_slave.inc
-SET GLOBAL debug_dbug=@save_dbug;
+SET GLOBAL debug_dbug=@saved_dbug;
 set @@global.slave_net_timeout= @restore_slave_net_timeout;
 include/start_slave.inc
 include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/r/rpl_incident.result b/mysql-test/suite/rpl/r/rpl_incident.result
index 8fb4aa907cc..6dbe4417c5a 100644
--- a/mysql-test/suite/rpl/r/rpl_incident.result
+++ b/mysql-test/suite/rpl/r/rpl_incident.result
@@ -14,6 +14,7 @@ a
 1
 2
 3
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug= '+d,incident_database_resync_on_replace,*';
 REPLACE INTO t1 VALUES (4);
 SELECT * FROM t1;
@@ -22,6 +23,7 @@ a
 2
 3
 4
+set @@global.debug_dbug = @saved_dbug;
 connection slave;
 call mtr.add_suppression("Slave SQL.*The incident LOST_EVENTS occurred on the master.* 1590");
 include/wait_for_slave_sql_error.inc [errno=1590]
diff --git a/mysql-test/suite/rpl/r/rpl_init_slave_errors.result b/mysql-test/suite/rpl/r/rpl_init_slave_errors.result
index 91742814b4c..fc23734c645 100644
--- a/mysql-test/suite/rpl/r/rpl_init_slave_errors.result
+++ b/mysql-test/suite/rpl/r/rpl_init_slave_errors.result
@@ -4,12 +4,13 @@ connection slave;
 stop slave;
 reset slave;
 connection slave;
+set @saved_dbug = @@global.debug_dbug;
 SET GLOBAL debug_dbug= "d,simulate_io_slave_error_on_init,simulate_sql_slave_error_on_init";
 start slave;
 include/wait_for_slave_sql_error.inc [errno=1593]
 Last_SQL_Error = 'Failed during slave thread initialization'
 call mtr.add_suppression("Failed during slave.* thread initialization");
-SET GLOBAL debug_dbug= "";
+set @@global.debug_dbug = @saved_dbug;
 connection slave;
 reset slave;
 SET GLOBAL init_slave= "garbage";
diff --git a/mysql-test/suite/rpl/r/rpl_row_big_table_id.result b/mysql-test/suite/rpl/r/rpl_row_big_table_id.result
index 7a0a964dc5e..4899dda5e5a 100644
--- a/mysql-test/suite/rpl/r/rpl_row_big_table_id.result
+++ b/mysql-test/suite/rpl/r/rpl_row_big_table_id.result
@@ -2,6 +2,7 @@ include/master-slave.inc
 [connection master]
 connection master;
 include/rpl_restart_server.inc [server_number=1]
+SET @saved_dbug = @@SESSION.debug_dbug;
 SET @@debug_dbug="d,simulate_big_table_id";
 CREATE TABLE t (a int);
 INSERT INTO t SET a= 0;
@@ -42,5 +43,6 @@ master-bin.000002	#	Query	1	#	COMMIT
 connection slave;
 connection master;
 DROP TABLE t;
+SET debug_dbug= @saved_dbug;
 connection slave;
 include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/r/rpl_row_find_row_debug.result b/mysql-test/suite/rpl/r/rpl_row_find_row_debug.result
index 269dc16733a..f1a0059a04f 100644
--- a/mysql-test/suite/rpl/r/rpl_row_find_row_debug.result
+++ b/mysql-test/suite/rpl/r/rpl_row_find_row_debug.result
@@ -2,6 +2,7 @@ include/master-slave.inc
 [connection master]
 connection slave;
 include/stop_slave.inc
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 SET GLOBAL log_warnings = 2;
 SET GLOBAL debug_dbug="d,inject_long_find_row_note";
 include/start_slave.inc
@@ -18,7 +19,7 @@ connection slave;
 FOUND 1 /The slave is applying a ROW event on behalf of an UPDATE statement on table t1 and is currently taking a considerable amount/ in mysqld.2.err
 FOUND 1 /The slave is applying a ROW event on behalf of a DELETE statement on table t1 and is currently taking a considerable amount/ in mysqld.2.err
 include/stop_slave.inc
-SET GLOBAL debug_dbug = '';
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 SET GLOBAL log_warnings = 2;
 include/start_slave.inc
 include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/r/rpl_semi_sync_skip_repl.result b/mysql-test/suite/rpl/r/rpl_semi_sync_skip_repl.result
index ec9607148d4..d517d53c6da 100644
--- a/mysql-test/suite/rpl/r/rpl_semi_sync_skip_repl.result
+++ b/mysql-test/suite/rpl/r/rpl_semi_sync_skip_repl.result
@@ -11,6 +11,7 @@ SET @@GLOBAL.rpl_semi_sync_slave_enabled = 1;
 include/start_slave.inc
 connection master;
 CREATE TABLE t1 (a INT) ENGINE=innodb;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 SET @@GLOBAL.debug_dbug="d,dbug_master_binlog_over_2GB";
 SET @@SESSION.skip_replication=1;
 INSERT INTO t1 SET a=1;
@@ -20,7 +21,7 @@ SET @@GLOBAL.debug_dbug="";
 FLUSH LOGS;
 connection slave;
 connection master;
-SET @@GLOBAL.debug_dbug=@@GLOBAL.debug_dbug;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 SET @@GLOBAL.rpl_semi_sync_master_timeout = 10000;
 SET @@GLOBAL.rpl_semi_sync_master_enabled = 0;
 connection master;
diff --git a/mysql-test/suite/rpl/r/rpl_show_slave_running.result b/mysql-test/suite/rpl/r/rpl_show_slave_running.result
index 729c718390a..353ff379776 100644
--- a/mysql-test/suite/rpl/r/rpl_show_slave_running.result
+++ b/mysql-test/suite/rpl/r/rpl_show_slave_running.result
@@ -3,6 +3,7 @@ include/master-slave.inc
 connection slave;
 SET DEBUG_SYNC= 'RESET';
 include/stop_slave.inc
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= 'd,dbug.before_get_running_status_yes';
 Slave_running, Slave_IO_Running, Slave_SQL_Running, must be OFF, NO, NO in three following queries
 SHOW STATUS LIKE 'Slave_running';
@@ -34,7 +35,7 @@ Slave_running	ON
 Slave_IO_Running= Yes
 Slave_SQL_Running= Yes
 connection slave;
-set global debug_dbug= '';
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 SET DEBUG_SYNC= 'RESET';
 End of tests
 include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/r/rpl_slave_load_remove_tmpfile.result b/mysql-test/suite/rpl/r/rpl_slave_load_remove_tmpfile.result
index be2a17ea2b7..8f855813554 100644
--- a/mysql-test/suite/rpl/r/rpl_slave_load_remove_tmpfile.result
+++ b/mysql-test/suite/rpl/r/rpl_slave_load_remove_tmpfile.result
@@ -1,6 +1,7 @@
 include/master-slave.inc
 [connection master]
 connection slave;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 SET @@global.debug_dbug= '+d,remove_slave_load_file_before_write';
 connection master;
 create table t1(a int not null auto_increment, b int, primary key(a)) engine=innodb;
@@ -21,5 +22,5 @@ call mtr.add_suppression("Slave: Can't get stat of .*");
 call mtr.add_suppression("Slave SQL: Error .Can.t get stat of.* error.* 13");
 call mtr.add_suppression("Slave: File.* not found.*");
 call mtr.add_suppression("Slave SQL: Error .File.* not found.* error.* 29");
-SET @@global.debug_dbug= '';
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/r/rpl_stop_slave.result b/mysql-test/suite/rpl/r/rpl_stop_slave.result
index 4b9c544527b..a4dbf13290a 100644
--- a/mysql-test/suite/rpl/r/rpl_stop_slave.result
+++ b/mysql-test/suite/rpl/r/rpl_stop_slave.result
@@ -15,7 +15,7 @@ include/stop_slave.inc
 # Suspend the INSERT statement in current transaction on SQL thread.
 # It guarantees that SQL thread is applying the transaction when
 # STOP SLAVE command launchs.
-set @old_debug=@@global.debug;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= '+d,after_mysql_insert';
 include/start_slave.inc
 
@@ -75,6 +75,7 @@ connection master;
 connection slave;
 
 # Test end
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 include/restart_slave.inc
 connection slave;
 call mtr.add_suppression("Slave SQL.*Request to stop slave SQL Thread received while applying a group that has non-transactional changes; waiting for completion of the group");
@@ -99,7 +100,7 @@ connection slave;
 include/stop_slave.inc
 connection master;
 include/stop_dump_threads.inc
-set @old_debug=@@global.debug;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= '+d,dump_thread_wait_before_send_xid';
 connection slave;
 include/start_slave.inc
@@ -122,6 +123,7 @@ connection slave;
 include/wait_for_slave_to_stop.inc
 connection slave1;
 connection master;
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 include/stop_dump_threads.inc
 connection slave1;
 include/start_slave.inc
diff --git a/mysql-test/suite/rpl/r/rpl_view_debug.result b/mysql-test/suite/rpl/r/rpl_view_debug.result
index 497f4303698..1ec3dda9daa 100644
--- a/mysql-test/suite/rpl/r/rpl_view_debug.result
+++ b/mysql-test/suite/rpl/r/rpl_view_debug.result
@@ -21,6 +21,7 @@ Tables_in_test
 t1
 v1
 connection master;
+SET @saved_dbug = @@SESSION.debug_dbug;
 set @@debug_dbug="d,simulate_register_view_failure";
 CREATE VIEW v2 as SELECT * FROM t1;
 ERROR HY000: Out of memory.
@@ -36,4 +37,5 @@ v1
 connection master;
 DROP VIEW IF EXISTS v1;
 DROP TABLE t1;
+SET debug_dbug= @saved_dbug;
 include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/t/kill_race_condition.test b/mysql-test/suite/rpl/t/kill_race_condition.test
index 0f3b44864fe..25a7b18bac2 100644
--- a/mysql-test/suite/rpl/t/kill_race_condition.test
+++ b/mysql-test/suite/rpl/t/kill_race_condition.test
@@ -7,6 +7,7 @@ create table t1 (a int);
 --sync_slave_with_master
 
 connection slave;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug='d,rows_log_event_before_open_table';
 
 connection master;
@@ -22,7 +23,7 @@ set debug_sync='now SIGNAL go_ahead_sql';
 --source include/wait_for_slave_sql_error.inc
 let $error= query_get_value(SHOW SLAVE STATUS, Last_SQL_Error, 1);
 --echo Last_SQL_Error = $error
-set global debug_dbug='';
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 set debug_sync='RESET';
 connection master;
 drop table t1;
diff --git a/mysql-test/suite/rpl/t/rpl_binlog_rollback_cleanup.test b/mysql-test/suite/rpl/t/rpl_binlog_rollback_cleanup.test
new file mode 100644
index 00000000000..ed4d713f626
--- /dev/null
+++ b/mysql-test/suite/rpl/t/rpl_binlog_rollback_cleanup.test
@@ -0,0 +1,46 @@
+# ==== Purpose ====
+#
+# Test verifies that when flushing an event to binary log fails the transaction
+# is successfully rolled back and following COMMIT command doesn't report any
+# assert.
+#
+# ==== Implementation ====
+#
+# Steps:
+#    0 - SET max_binlog_cache_size=64K
+#    1 - Create an Innodb table and insert required amount of data. Execute an
+#        UPDATE operation which generates a big update event whose size exceeds
+#        max_binlog_cache_size.
+#    2 - Wait for error 1197. Execute COMMIT command.
+#    3 - COMMIT should be successful.
+#
+# ==== References ====
+#
+# MDEV-18514: Assertion `!writer.checksum_len || writer.remains == 0' failed
+#
+--source include/have_innodb.inc
+--source include/have_binlog_format_row.inc
+--source include/master-slave.inc
+--connection master
+let $old_max_binlog_cache_size= query_get_value(SHOW VARIABLES LIKE "max_binlog_cache_size", Value, 1);
+SET GLOBAL max_binlog_cache_size = 65536;
+CREATE TABLE t1(a INT PRIMARY KEY, data VARCHAR(30000)) ENGINE=INNODB;
+let $data = `select concat('"', repeat('a',6000), '"')`;
+let $data1 = `select concat('"', repeat('b',6000), '"')`;
+--disable_query_log
+eval INSERT INTO t1 (a, data) VALUES (1, CONCAT($data, $data));
+eval INSERT INTO t1 (a, data) VALUES (2, CONCAT($data, $data));
+eval INSERT INTO t1 (a, data) VALUES (3, CONCAT($data, $data));
+eval INSERT INTO t1 (a, data) VALUES (4, CONCAT($data, $data));
+eval INSERT INTO t1 (a, data) VALUES (5, CONCAT($data, $data));
+START TRANSACTION;
+--error ER_TRANS_CACHE_FULL
+eval UPDATE t1 SET data=$data1;
+COMMIT;
+--enable_query_log
+
+--replace_result $old_max_binlog_cache_size ORIGINAL_VALUE
+--eval SET GLOBAL max_binlog_cache_size= $old_max_binlog_cache_size
+DROP TABLE t1;
+
+--source include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/t/rpl_bug33931.test b/mysql-test/suite/rpl/t/rpl_bug33931.test
index 2273219a821..0b2cbb6365c 100644
--- a/mysql-test/suite/rpl/t/rpl_bug33931.test
+++ b/mysql-test/suite/rpl/t/rpl_bug33931.test
@@ -15,6 +15,7 @@ call mtr.add_suppression("Slave SQL.*Failed during slave thread initialization.*
 reset slave;
 
 # Set debug flags on slave to force errors to occur
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 SET GLOBAL debug_dbug="d,simulate_io_slave_error_on_init,simulate_sql_slave_error_on_init";
 
 --disable_query_log
@@ -39,7 +40,7 @@ start slave;
 #
 # Cleanup
 #
-SET GLOBAL debug_dbug="";
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
 # Clear Last_SQL_Error
 RESET SLAVE;
diff --git a/mysql-test/suite/rpl/t/rpl_bug41902.test b/mysql-test/suite/rpl/t/rpl_bug41902.test
index fe9452b0eda..bb6c572580f 100644
--- a/mysql-test/suite/rpl/t/rpl_bug41902.test
+++ b/mysql-test/suite/rpl/t/rpl_bug41902.test
@@ -15,7 +15,7 @@ source include/master-slave.inc;
 
 connection slave;
 stop slave;
-
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 SET @@debug_dbug="d,simulate_find_log_pos_error";
 
 --error ER_UNKNOWN_TARGET_BINLOG
@@ -36,6 +36,7 @@ reset slave;
 change master to master_host='dummy';
 
 connection master;
+SET @saved_dbug_m = @@global.debug_dbug;
 SET @@debug_dbug="d,simulate_find_log_pos_error";
 --error ER_UNKNOWN_TARGET_BINLOG
 reset master;
@@ -53,10 +54,12 @@ purge binary logs to 'master-bin.000001';
 --disable_query_log
 call mtr.add_suppression("Failed to locate old binlog or relay log files");
 call mtr.add_suppression("MYSQL_BIN_LOG::purge_logs was called with file ..master-bin.000001 not listed in the index");
+set @@global.debug_dbug = @saved_dbug_m;
 connection slave;
 call mtr.add_suppression("Failed to locate old binlog or relay log files");
 call mtr.add_suppression("MYSQL_BIN_LOG::purge_logs was called with file ..master-bin.000001 not listed in the index");
 --enable_query_log
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
 --echo ==== clean up ====
 CHANGE MASTER TO MASTER_HOST = '127.0.0.1';
diff --git a/mysql-test/suite/rpl/t/rpl_get_master_version_and_clock.test b/mysql-test/suite/rpl/t/rpl_get_master_version_and_clock.test
index 9c4cc1bc34d..02665c70b9e 100644
--- a/mysql-test/suite/rpl/t/rpl_get_master_version_and_clock.test
+++ b/mysql-test/suite/rpl/t/rpl_get_master_version_and_clock.test
@@ -26,7 +26,7 @@ call mtr.add_suppression("Fatal error: The slave I/O thread stops because master
 call mtr.add_suppression("Slave I/O thread .* register on master");
 
 #Test case 1: Try to get the value of the UNIX_TIMESTAMP from master under network disconnection
-let $debug_saved= `select @@global.debug`;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 
 # set up two parameters to pass into include/rpl_get_master_version_and_clock
 let $dbug_sync_point= 'debug_lock.before_get_UNIX_TIMESTAMP';
@@ -40,11 +40,9 @@ let $dbug_sync_point= 'debug_lock.before_get_SERVER_ID';
 let $debug_sync_action= 'now SIGNAL signal.get_server_id';
 source include/rpl_get_master_version_and_clock.test;
 
-eval set global debug_dbug= '$debug_saved';
-
 
 # cleanup
-
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 # is not really necessary but avoids mtr post-run env check warnings
 SET DEBUG_SYNC= 'RESET';
 
diff --git a/mysql-test/suite/rpl/t/rpl_heartbeat_debug.test b/mysql-test/suite/rpl/t/rpl_heartbeat_debug.test
index 6a426ed1e9f..bd66a249ada 100644
--- a/mysql-test/suite/rpl/t/rpl_heartbeat_debug.test
+++ b/mysql-test/suite/rpl/t/rpl_heartbeat_debug.test
@@ -18,7 +18,7 @@ set @@global.slave_net_timeout= 10;
 # default period slave_net_timeout/2
 #
 --query_vertical show status like 'Slave_heartbeat_period';
-SET @save_dbug= @@GLOBAL.debug_dbug;
+SET @saved_dbug= @@GLOBAL.debug_dbug;
 SET GLOBAL debug_dbug="+d,simulate_slave_heartbeat_network_error";
 CALL mtr.add_suppression('SET @master_heartbeat_period to master failed with error');
 CALL mtr.add_suppression('Master command COM_REGISTER_SLAVE failed: failed registering on master, reconnecting to try again');
@@ -44,7 +44,7 @@ drop table t1;
 connection slave;
 --source include/stop_slave.inc
 --disable_warnings
-SET GLOBAL debug_dbug=@save_dbug;
+SET GLOBAL debug_dbug=@saved_dbug;
 set @@global.slave_net_timeout= @restore_slave_net_timeout;
 --enable_warnings
 --source include/start_slave.inc
diff --git a/mysql-test/suite/rpl/t/rpl_row_big_table_id.test b/mysql-test/suite/rpl/t/rpl_row_big_table_id.test
index 0c6f9d5e862..abf22cc876e 100644
--- a/mysql-test/suite/rpl/t/rpl_row_big_table_id.test
+++ b/mysql-test/suite/rpl/t/rpl_row_big_table_id.test
@@ -17,6 +17,7 @@
 --let $rpl_server_number= 1
 --source include/rpl_restart_server.inc
 
+SET @saved_dbug = @@SESSION.debug_dbug;
 SET @@debug_dbug="d,simulate_big_table_id";
 CREATE TABLE t (a int);
 
@@ -51,7 +52,7 @@ if (`SELECT sum(a) != 6 FROM t`)
 
 --connection master
 DROP TABLE t;
-
+SET debug_dbug= @saved_dbug;
 --sync_slave_with_master
 
 --source include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/t/rpl_row_find_row_debug.test b/mysql-test/suite/rpl/t/rpl_row_find_row_debug.test
index 9c0ee1cdbbb..e3edabe239d 100644
--- a/mysql-test/suite/rpl/t/rpl_row_find_row_debug.test
+++ b/mysql-test/suite/rpl/t/rpl_row_find_row_debug.test
@@ -9,7 +9,7 @@
 # - setup log_warnings and debug 
 --connection slave
 --source include/stop_slave.inc
---let $debug_save= `SELECT @@GLOBAL.debug_dbug`
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 --let $log_warnings_save= `SELECT @@GLOBAL.log_warnings`
 
 SET GLOBAL log_warnings = 2;
@@ -50,7 +50,7 @@ DROP TABLE t1;
 
 # cleanup
 --source include/stop_slave.inc
---eval SET GLOBAL debug_dbug = '$debug_save'
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 --eval SET GLOBAL log_warnings = $log_warnings_save
 --source include/start_slave.inc
 
diff --git a/mysql-test/suite/rpl/t/rpl_row_index_choice.test b/mysql-test/suite/rpl/t/rpl_row_index_choice.test
index 0ad9b315d66..958fa2352c2 100644
--- a/mysql-test/suite/rpl/t/rpl_row_index_choice.test
+++ b/mysql-test/suite/rpl/t/rpl_row_index_choice.test
@@ -47,6 +47,7 @@ sync_slave_with_master;
 connection slave;
 ANALYZE TABLE t2;
 --echo # Slave will crash if using the wrong or no index
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 SET GLOBAL debug_dbug="+d,slave_crash_if_wrong_index,slave_crash_if_table_scan";
 
 connection master;
@@ -238,6 +239,5 @@ connection master;
 DROP TABLE t1;
 sync_slave_with_master;
 connection slave;
-SET GLOBAL debug_dbug="";
-
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 --source include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/t/rpl_semi_sync_skip_repl.test b/mysql-test/suite/rpl/t/rpl_semi_sync_skip_repl.test
index 8dd30b8a161..587e1290187 100644
--- a/mysql-test/suite/rpl/t/rpl_semi_sync_skip_repl.test
+++ b/mysql-test/suite/rpl/t/rpl_semi_sync_skip_repl.test
@@ -32,7 +32,7 @@ source include/start_slave.inc;
 CREATE TABLE t1 (a INT) ENGINE=innodb;
 
 # Make the following events as if they offset over 2GB from the beginning of binlog
---let $sav_debug_dbug=@@GLOBAL.debug_dbug
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 SET @@GLOBAL.debug_dbug="d,dbug_master_binlog_over_2GB";
 SET @@SESSION.skip_replication=1;
 INSERT INTO t1 SET a=1;
@@ -50,7 +50,7 @@ FLUSH LOGS;
 # Clean up
 #
 --connection master
---eval SET @@GLOBAL.debug_dbug=$sav_debug_dbug
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 --eval SET @@GLOBAL.rpl_semi_sync_master_timeout = $sav_timeout_master
 --eval SET @@GLOBAL.rpl_semi_sync_master_enabled = $sav_enabled_master
 
diff --git a/mysql-test/suite/rpl/t/rpl_show_slave_running.test b/mysql-test/suite/rpl/t/rpl_show_slave_running.test
index 2cb44fc6ac1..cb4a8819a5b 100644
--- a/mysql-test/suite/rpl/t/rpl_show_slave_running.test
+++ b/mysql-test/suite/rpl/t/rpl_show_slave_running.test
@@ -11,7 +11,7 @@ connection slave;
 
 SET DEBUG_SYNC= 'RESET';
 source include/stop_slave.inc;
-let $debug_saved= `select @@global.debug`;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= 'd,dbug.before_get_running_status_yes'; # to block due-started IO
 
 # Test 1. Slave is stopped
@@ -77,7 +77,7 @@ echo Slave_SQL_Running= $status;
 
 connection slave;
 
-eval set global debug_dbug= '$debug_saved';
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 SET DEBUG_SYNC= 'RESET';
 --echo End of tests
 --source include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/t/rpl_slave_load_remove_tmpfile.test b/mysql-test/suite/rpl/t/rpl_slave_load_remove_tmpfile.test
index 69319bad4a0..100514089d5 100644
--- a/mysql-test/suite/rpl/t/rpl_slave_load_remove_tmpfile.test
+++ b/mysql-test/suite/rpl/t/rpl_slave_load_remove_tmpfile.test
@@ -29,7 +29,7 @@
 ##########################################################################
 
 connection slave;
---let $old_debug= `SELECT @@global.debug_dbug`
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 SET @@global.debug_dbug= '+d,remove_slave_load_file_before_write';
 
 connection master;
@@ -74,7 +74,7 @@ call mtr.add_suppression("Slave: File.* not found.*");
 call mtr.add_suppression("Slave SQL: Error .File.* not found.* error.* 29");
 --let $rpl_only_running_threads= 1
 
-eval SET @@global.debug_dbug= '$old_debug';
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 
 --source include/rpl_end.inc
 
diff --git a/mysql-test/suite/rpl/t/rpl_stop_slave.test b/mysql-test/suite/rpl/t/rpl_stop_slave.test
index 291524126ec..17efa7ade3b 100644
--- a/mysql-test/suite/rpl/t/rpl_stop_slave.test
+++ b/mysql-test/suite/rpl/t/rpl_stop_slave.test
@@ -22,7 +22,7 @@ source include/stop_slave.inc;
 --echo # Suspend the INSERT statement in current transaction on SQL thread.
 --echo # It guarantees that SQL thread is applying the transaction when
 --echo # STOP SLAVE command launchs.
-set @old_debug=@@global.debug;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= '+d,after_mysql_insert';
 source include/start_slave.inc;
 
@@ -44,9 +44,7 @@ source include/rpl_stop_slave.test;
 
 --echo
 --echo # Test end
---disable_query_log
-set global debug_dbug= @old_debug;
---enable_query_log
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 source include/restart_slave_sql.inc;
 
 connection slave;
@@ -79,7 +77,7 @@ connection master;
 # make sure that there are no zombie threads
 --source include/stop_dump_threads.inc
 
-set @old_debug=@@global.debug;
+SET @saved_dbug = @@GLOBAL.debug_dbug;
 set global debug_dbug= '+d,dump_thread_wait_before_send_xid';
 
 connection slave;
@@ -126,9 +124,7 @@ reap;
 # sure that we disable the DBUG_EXECUTE_IF
 # that would set the dump thread to wait
 connection master;
---disable_query_log
-set global debug_dbug= @old_debug;
---enable_query_log
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 # make sure that there are no zombie threads
 --source include/stop_dump_threads.inc
 
diff --git a/mysql-test/suite/rpl/t/rpl_view_debug.test b/mysql-test/suite/rpl/t/rpl_view_debug.test
index a00b6733dea..0803692496e 100644
--- a/mysql-test/suite/rpl/t/rpl_view_debug.test
+++ b/mysql-test/suite/rpl/t/rpl_view_debug.test
@@ -18,6 +18,7 @@ sync_slave_with_master;
 # view already has to be on slave
 show tables;
 connection master;
+SET @saved_dbug = @@SESSION.debug_dbug;
 set @@debug_dbug="d,simulate_register_view_failure";
 
 --error ER_OUT_OF_RESOURCES
@@ -30,5 +31,5 @@ show tables;
 connection master;
 DROP VIEW IF EXISTS v1;
 DROP TABLE t1;
-
+SET debug_dbug= @saved_dbug;
 --source include/rpl_end.inc
diff --git a/mysql-test/suite/sys_vars/r/debug_dbug_func.result b/mysql-test/suite/sys_vars/r/debug_dbug_func.result
index 1c7ae4e2832..64b9c1a759b 100644
--- a/mysql-test/suite/sys_vars/r/debug_dbug_func.result
+++ b/mysql-test/suite/sys_vars/r/debug_dbug_func.result
@@ -1,13 +1,13 @@
 SET @old_debug = @@GLOBAL.debug;
-set debug_dbug= 'T';
+SET debug_dbug= 'T';
 select @@debug;
 @@debug
 T
-set debug_dbug= '+P';
+SET debug_dbug= '+P';
 select @@debug;
 @@debug
 P:T
-set debug_dbug= '-P';
+SET debug_dbug= '-P';
 select @@debug;
 @@debug
 T
diff --git a/mysql-test/suite/sys_vars/t/debug_dbug_func.test b/mysql-test/suite/sys_vars/t/debug_dbug_func.test
index b4cd4aefd5e..136a4c5504d 100644
--- a/mysql-test/suite/sys_vars/t/debug_dbug_func.test
+++ b/mysql-test/suite/sys_vars/t/debug_dbug_func.test
@@ -6,11 +6,11 @@ SET @old_debug = @@GLOBAL.debug;
 # Bug#34678 @@debug variable's incremental mode
 #
 
-set debug_dbug= 'T';
+SET debug_dbug= 'T';
 select @@debug;
-set debug_dbug= '+P';
+SET debug_dbug= '+P';
 select @@debug;
-set debug_dbug= '-P';
+SET debug_dbug= '-P';
 select @@debug;
 
 #
diff --git a/mysql-test/suite/wsrep/disabled.def b/mysql-test/suite/wsrep/disabled.def
index bd8d4ecf33b..0e2027b7153 100644
--- a/mysql-test/suite/wsrep/disabled.def
+++ b/mysql-test/suite/wsrep/disabled.def
@@ -10,4 +10,4 @@
 #
 ##############################################################################
 
-variables : MDEV-20581 Crash on wsrep.variables test case
+variables : MDEV-17585,MDEV-20581 Crash on wsrep.variables test case
diff --git a/mysql-test/suite/wsrep/t/binlog_format.opt b/mysql-test/suite/wsrep/t/binlog_format.opt
new file mode 100644
index 00000000000..299096e5aa5
--- /dev/null
+++ b/mysql-test/suite/wsrep/t/binlog_format.opt
@@ -0,0 +1 @@
+--wsrep-on=1
diff --git a/sql/item_func.cc b/sql/item_func.cc
index e66fe12c57f..f3d7528b68f 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -123,7 +123,8 @@ Item_args::Item_args(THD *thd, const Item_args *other)
     arg_count= 0;
     return;
   }
-  memcpy(args, other->args, sizeof(Item*) * arg_count);
+  if (arg_count)
+    memcpy(args, other->args, sizeof(Item*) * arg_count);
 }
 
 
diff --git a/sql/log.cc b/sql/log.cc
index d7878db6901..af22c4993bb 100644
--- a/sql/log.cc
+++ b/sql/log.cc
@@ -488,6 +488,7 @@ private:
   void truncate(my_off_t pos, bool reset_cache=0)
   {
     DBUG_PRINT("info", ("truncating to position %lu", (ulong) pos));
+    cache_log.error=0;
     if (pending())
     {
       delete pending();
@@ -496,7 +497,7 @@ private:
     reinit_io_cache(&cache_log, WRITE_CACHE, pos, 0, reset_cache);
     cache_log.end_of_file= saved_max_binlog_cache_size;
   }
- 
+
   binlog_cache_data& operator=(const binlog_cache_data& info);
   binlog_cache_data(const binlog_cache_data& info);
 };
diff --git a/sql/sp.cc b/sql/sp.cc
index 751e4644da0..e8611159df0 100644
--- a/sql/sp.cc
+++ b/sql/sp.cc
@@ -855,7 +855,7 @@ static sp_head *sp_compile(THD *thd, String *defstr, sql_mode_t sql_mode,
   if (parse_sql(thd, & parser_state, creation_ctx) || thd->lex == NULL)
   {
     sp= thd->lex->sphead;
-    delete sp;
+    sp_head::destroy(sp);
     sp= 0;
   }
   else
diff --git a/sql/sp_cache.cc b/sql/sp_cache.cc
index 99e68cd2595..e4ffbdcb155 100644
--- a/sql/sp_cache.cc
+++ b/sql/sp_cache.cc
@@ -283,7 +283,7 @@ uchar *hash_get_key_for_sp_head(const uchar *ptr, size_t *plen,
 void hash_free_sp_head(void *p)
 {
   sp_head *sp= (sp_head *)p;
-  delete sp;
+  sp_head::destroy(sp);
 }
 
 
diff --git a/sql/sp_head.cc b/sql/sp_head.cc
index eb3c35a4492..6f1b720806c 100644
--- a/sql/sp_head.cc
+++ b/sql/sp_head.cc
@@ -1,6 +1,6 @@
 /*
    Copyright (c) 2002, 2016, Oracle and/or its affiliates.
-   Copyright (c) 2011, 2017, MariaDB
+   Copyright (c) 2011, 2020, 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
@@ -451,49 +451,47 @@ check_routine_name(const LEX_CSTRING *ident)
  *  sp_head
  *
  */
-
-void *
-sp_head::operator new(size_t size) throw()
+ 
+sp_head *sp_head::create(sp_package *parent, const Sp_handler *handler,
+                         enum_sp_aggregate_type agg_type)
 {
-  DBUG_ENTER("sp_head::operator new");
   MEM_ROOT own_root;
+  init_sql_alloc(&own_root, "sp_head", MEM_ROOT_BLOCK_SIZE, MEM_ROOT_PREALLOC,
+                 MYF(0));
   sp_head *sp;
+  if (!(sp= new (&own_root) sp_head(&own_root, parent, handler, agg_type)))
+    free_root(&own_root, MYF(0));
 
-  init_sql_alloc(&own_root, "sp_head",
-                 MEM_ROOT_BLOCK_SIZE, MEM_ROOT_PREALLOC, MYF(0));
-  sp= (sp_head *) alloc_root(&own_root, size);
-  if (sp == NULL)
-    DBUG_RETURN(NULL);
-  sp->main_mem_root= own_root;
-  DBUG_PRINT("info", ("mem_root %p", &sp->mem_root));
-  DBUG_RETURN(sp);
+  return sp;
 }
 
-void
-sp_head::operator delete(void *ptr, size_t size) throw()
-{
-  DBUG_ENTER("sp_head::operator delete");
-  MEM_ROOT own_root;
 
-  if (ptr == NULL)
-    DBUG_VOID_RETURN;
-
-  sp_head *sp= (sp_head *) ptr;
-
-  /* Make a copy of main_mem_root as free_root will free the sp */
-  own_root= sp->main_mem_root;
-  DBUG_PRINT("info", ("mem_root %p moved to %p",
-                      &sp->mem_root, &own_root));
-  free_root(&own_root, MYF(0));
-
-  DBUG_VOID_RETURN;
+void sp_head::destroy(sp_head *sp)
+{
+  if (sp)
+  {
+    /* Make a copy of main_mem_root as free_root will free the sp */
+    MEM_ROOT own_root= sp->main_mem_root;
+    DBUG_PRINT("info", ("mem_root %p moved to %p",
+                        &sp->mem_root, &own_root));
+    delete sp;
+
+ 
+    free_root(&own_root, MYF(0));
+  }
 }
 
+/*
+ *
+ *  sp_head
+ *
+ */
 
-sp_head::sp_head(sp_package *parent, const Sp_handler *sph,
-                 enum_sp_aggregate_type agg_type)
-  :Query_arena(&main_mem_root, STMT_INITIALIZED_FOR_SP),
+sp_head::sp_head(MEM_ROOT *mem_root_arg, sp_package *parent,
+                 const Sp_handler *sph, enum_sp_aggregate_type agg_type)
+  :Query_arena(NULL, STMT_INITIALIZED_FOR_SP),
    Database_qualified_name(&null_clex_str, &null_clex_str),
+   main_mem_root(*mem_root_arg),
    m_parent(parent),
    m_handler(sph),
    m_flags(0),
@@ -524,6 +522,8 @@ sp_head::sp_head(sp_package *parent, const Sp_handler *sph,
    m_pcont(new (&main_mem_root) sp_pcontext()),
    m_cont_level(0)
 {
+  mem_root= &main_mem_root;
+
   set_chistics_agg_type(agg_type);
   m_first_instance= this;
   m_first_free_instance= this;
@@ -548,10 +548,25 @@ sp_head::sp_head(sp_package *parent, const Sp_handler *sph,
 }
 
 
-sp_package::sp_package(LEX *top_level_lex,
+sp_package *sp_package::create(LEX *top_level_lex, const sp_name *name,
+                               const Sp_handler *sph)
+{
+  MEM_ROOT own_root;
+  init_sql_alloc(&own_root, "sp_package", MEM_ROOT_BLOCK_SIZE,
+                 MEM_ROOT_PREALLOC, MYF(0));
+  sp_package *sp;
+  if (!(sp= new (&own_root) sp_package(&own_root, top_level_lex, name, sph)))
+    free_root(&own_root, MYF(0));
+
+  return sp;
+}
+
+
+sp_package::sp_package(MEM_ROOT *mem_root_arg,
+                       LEX *top_level_lex,
                        const sp_name *name,
                        const Sp_handler *sph)
- :sp_head(NULL, sph, DEFAULT_AGGREGATE),
+ :sp_head(mem_root_arg, NULL, sph, DEFAULT_AGGREGATE),
   m_current_routine(NULL),
   m_top_level_lex(top_level_lex),
   m_rcontext(NULL),
@@ -569,7 +584,7 @@ sp_package::~sp_package()
   m_routine_declarations.cleanup();
   m_body= null_clex_str;
   if (m_current_routine)
-    delete m_current_routine->sphead;
+    sp_head::destroy(m_current_routine->sphead);
   delete m_rcontext;
 }
 
@@ -826,7 +841,7 @@ sp_head::~sp_head()
   my_hash_free(&m_sptabs);
   my_hash_free(&m_sroutines);
 
-  delete m_next_cached_sp;
+  sp_head::destroy(m_next_cached_sp);
 
   DBUG_VOID_RETURN;
 }
diff --git a/sql/sp_head.h b/sql/sp_head.h
index 3085c248924..6cf4610c466 100644
--- a/sql/sp_head.h
+++ b/sql/sp_head.h
@@ -1,6 +1,7 @@
 /* -*- C++ -*- */
 /*
    Copyright (c) 2002, 2011, Oracle and/or its affiliates.
+   Copyright (c) 2020, 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
@@ -124,10 +125,11 @@ bool
 check_routine_name(const LEX_CSTRING *ident);
 
 class sp_head :private Query_arena,
-               public Database_qualified_name
+               public Database_qualified_name,
+               public Sql_alloc
 {
-  sp_head(const sp_head &);	/**< Prevent use of these */
-  void operator=(sp_head &);
+  sp_head(const sp_head &)= delete;
+  void operator=(sp_head &)= delete;
 
 protected:
   MEM_ROOT main_mem_root;
@@ -318,14 +320,14 @@ public:
   */
   SQL_I_List<Item_trigger_field> m_trg_table_fields;
 
-  static void *
-  operator new(size_t size) throw ();
-
-  static void
-  operator delete(void *ptr, size_t size) throw ();
-
-  sp_head(sp_package *parent, const Sp_handler *handler,
-          enum_sp_aggregate_type);
+protected:
+  sp_head(MEM_ROOT *mem_root, sp_package *parent, const Sp_handler *handler,
+          enum_sp_aggregate_type agg_type);
+  virtual ~sp_head();
+public:
+  static void destroy(sp_head *sp);
+  static sp_head *create(sp_package *parent, const Sp_handler *handler,
+                         enum_sp_aggregate_type agg_type);
 
   /// Initialize after we have reset mem_root
   void
@@ -343,7 +345,6 @@ public:
   void
   set_stmt_end(THD *thd);
 
-  virtual ~sp_head();
 
   bool
   execute_trigger(THD *thd,
@@ -968,10 +969,16 @@ public:
   bool m_is_instantiated;
   bool m_is_cloning_routine;
 
-  sp_package(LEX *top_level_lex,
+private:
+  sp_package(MEM_ROOT *mem_root,
+             LEX *top_level_lex,
              const sp_name *name,
              const Sp_handler *sph);
   ~sp_package();
+public:
+  static sp_package *create(LEX *top_level_lex, const sp_name *name,
+                            const Sp_handler *sph);
+
   bool add_routine_declaration(LEX *lex)
   {
     return m_routine_declarations.check_dup_qualified(lex->sphead) ||
diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc
index 6539b1e471f..33bc8eef651 100644
--- a/sql/sql_lex.cc
+++ b/sql/sql_lex.cc
@@ -815,7 +815,7 @@ void lex_end_stage1(LEX *lex)
   }
   else
   {
-    delete lex->sphead;
+    sp_head::destroy(lex->sphead);
     lex->sphead= NULL;
   }
 
@@ -3130,13 +3130,13 @@ void LEX::cleanup_lex_after_parse_error(THD *thd)
       DBUG_ASSERT(pkg == pkg->m_top_level_lex->sphead);
       pkg->restore_thd_mem_root(thd);
       LEX *top= pkg->m_top_level_lex;
-      delete pkg;
+      sp_package::destroy(pkg);
       thd->lex= top;
       thd->lex->sphead= NULL;
     }
     else
     {
-      delete thd->lex->sphead;
+      sp_head::destroy(thd->lex->sphead);
       thd->lex->sphead= NULL;
     }
   }
@@ -6515,7 +6515,7 @@ sp_head *LEX::make_sp_head(THD *thd, const sp_name *name,
   sp_head *sp;
 
   /* Order is important here: new - reset - init */
-  if (likely((sp= new sp_head(package, sph, agg_type))))
+  if (likely((sp= sp_head::create(package, sph, agg_type))))
   {
     sp->reset_thd_mem_root(thd);
     sp->init(this);
@@ -8411,7 +8411,7 @@ sp_package *LEX::create_package_start(THD *thd,
       return 0;
     }
   }
-  if (unlikely(!(pkg= new sp_package(this, name_arg, sph))))
+  if (unlikely(!(pkg= sp_package::create(this, name_arg, sph))))
     return NULL;
   pkg->reset_thd_mem_root(thd);
   pkg->init(this);
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index d89cae39330..2c74f15aa17 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -5176,7 +5176,7 @@ mysql_execute_command(THD *thd)
   /* Don't do it, if we are inside a SP */
   if (!thd->spcont)
   {
-    delete lex->sphead;
+    sp_head::destroy(lex->sphead);
     lex->sphead= NULL;
   }
   /* lex->unit.cleanup() is called outside, no need to call it here */
diff --git a/sql/sql_prepare.cc b/sql/sql_prepare.cc
index 5bf4e0a9c2f..3f8a9df1efe 100644
--- a/sql/sql_prepare.cc
+++ b/sql/sql_prepare.cc
@@ -3868,7 +3868,7 @@ Prepared_statement::~Prepared_statement()
   free_items();
   if (lex)
   {
-    delete lex->sphead;
+    sp_head::destroy(lex->sphead);
     delete lex->result;
     delete (st_lex_local *) lex;
   }
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 0e0c5c94387..7914a7165a2 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -11596,6 +11596,13 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
 	  if (i != join->const_tables && tab->use_quick != 2 &&
               !tab->first_inner)
 	  {					/* Read with cache */
+            /*
+              TODO: the execution also gets here when we will not be using
+              join buffer. Review these cases and perhaps, remove this call.
+              (The final decision whether to use join buffer is made in
+              check_join_cache_usage, so we should only call make_scan_filter()
+              there, too).
+            */
             if (tab->make_scan_filter())
               DBUG_RETURN(1);
           }
@@ -12572,6 +12579,9 @@ uint check_join_cache_usage(JOIN_TAB *tab,
     if ((tab->cache= new (root) JOIN_CACHE_BNL(join, tab, prev_cache)))
     {
       tab->icp_other_tables_ok= FALSE;
+      /* If make_join_select() hasn't called make_scan_filter(), do it now */
+      if (!tab->cache_select && tab->make_scan_filter())
+        goto no_join_cache;
       return (2 - MY_TEST(!prev_cache));
     }
     goto no_join_cache;
@@ -15245,12 +15255,15 @@ static int compare_fields_by_table_order(Item *field1,
 {
   int cmp= 0;
   bool outer_ref= 0;
-  Item_field *f1= (Item_field *) (field1->real_item());
-  Item_field *f2= (Item_field *) (field2->real_item());
-  if (field1->const_item() || f1->const_item())
+  Item *field1_real= field1->real_item();
+  Item *field2_real= field2->real_item();
+
+  if (field1->const_item() || field1_real->const_item())
     return -1;
-  if (field2->const_item() || f2->const_item())
+  if (field2->const_item() || field2_real->const_item())
     return 1;
+  Item_field *f1= (Item_field *) field1_real;
+  Item_field *f2= (Item_field *) field2_real;
   if (f1->used_tables() & OUTER_REF_TABLE_BIT)
   {
     outer_ref= 1;
diff --git a/sql/sql_show.cc b/sql/sql_show.cc
index 03de557b400..0f9537ff704 100644
--- a/sql/sql_show.cc
+++ b/sql/sql_show.cc
@@ -6367,7 +6367,7 @@ bool store_schema_params(THD *thd, TABLE *table, TABLE *proc_table,
       {
         free_table_share(&share);
         if (free_sp_head)
-          delete sp;
+          sp_head::destroy(sp);
         DBUG_RETURN(1);
       }
     }
@@ -6414,7 +6414,7 @@ bool store_schema_params(THD *thd, TABLE *table, TABLE *proc_table,
       }
     }
     if (free_sp_head)
-      delete sp;
+      sp_head::destroy(sp);
   }
   free_table_share(&share);
   DBUG_RETURN(error);
@@ -6492,7 +6492,7 @@ bool store_schema_proc(THD *thd, TABLE *table, TABLE *proc_table,
           store_column_type(table, field, cs, 5);
           free_table_share(&share);
           if (free_sp_head)
-            delete sp;
+            sp_head::destroy(sp);
         }
       }
 
diff --git a/sql/sql_trigger.cc b/sql/sql_trigger.cc
index f9b9e4dd4f1..5802d2c811e 100644
--- a/sql/sql_trigger.cc
+++ b/sql/sql_trigger.cc
@@ -329,7 +329,7 @@ public:
 
 Trigger::~Trigger()
 {
-  delete body;
+  sp_head::destroy(body);
 }
 
 
diff --git a/storage/innobase/btr/btr0cur.cc b/storage/innobase/btr/btr0cur.cc
index 19fc659f76f..f58628c5113 100644
--- a/storage/innobase/btr/btr0cur.cc
+++ b/storage/innobase/btr/btr0cur.cc
@@ -1,9 +1,9 @@
 /*****************************************************************************
 
-Copyright (c) 1994, 2018, Oracle and/or its affiliates. All Rights Reserved.
+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, 2019, MariaDB Corporation.
+Copyright (c) 2015, 2020, MariaDB Corporation.
 
 Portions of this file contain modifications contributed and copyrighted by
 Google, Inc. Those modifications are gratefully acknowledged and are described
@@ -940,46 +940,66 @@ btr_cur_will_modify_tree(
 	const ulint n_recs = page_get_n_recs(page);
 
 	if (lock_intention <= BTR_INTENTION_BOTH) {
-		ulint	margin;
+		compile_time_assert(BTR_INTENTION_DELETE < BTR_INTENTION_BOTH);
+		compile_time_assert(BTR_INTENTION_BOTH < BTR_INTENTION_INSERT);
 
-		/* check delete will cause. (BTR_INTENTION_BOTH
-		or BTR_INTENTION_DELETE) */
-		/* first, 2nd, 2nd-last and last records are 4 records */
-		if (n_recs < 5) {
-			return(true);
+		if (!page_has_siblings(page)) {
+			return true;
 		}
 
-		/* is first, 2nd or last record */
-		if (page_rec_is_first(rec, page)
-		    || (page_has_next(page)
-			&& (page_rec_is_last(rec, page)
-			    || page_rec_is_second_last(rec, page)))
-		    || (page_has_prev(page)
-			&& page_rec_is_second(rec, page))) {
-			return(true);
-		}
+		ulint margin = rec_size;
 
 		if (lock_intention == BTR_INTENTION_BOTH) {
+			ulint	level = btr_page_get_level(page);
+
+			/* This value is the worst expectation for the node_ptr
+			records to be deleted from this page. It is used to
+			expect whether the cursor position can be the left_most
+			record in this page or not. */
+			ulint   max_nodes_deleted = 0;
+
+			/* By modifying tree operations from the under of this
+			level, logically (2 ^ (level - 1)) opportunities to
+			deleting records in maximum even unreally rare case. */
+			if (level > 7) {
+				/* TODO: adjust this practical limit. */
+				max_nodes_deleted = 64;
+			} else if (level > 0) {
+				max_nodes_deleted = (ulint)1 << (level - 1);
+			}
+			/* check delete will cause. (BTR_INTENTION_BOTH
+			or BTR_INTENTION_DELETE) */
+			if (n_recs <= max_nodes_deleted * 2
+			    || page_rec_is_first(rec, page)) {
+				/* The cursor record can be the left most record
+				in this page. */
+				return true;
+			}
+
+			if (page_has_prev(page)
+			    && page_rec_distance_is_at_most(
+				    page_get_infimum_rec(page), rec,
+				    max_nodes_deleted)) {
+				return true;
+			}
+
+			if (page_has_next(page)
+			    && page_rec_distance_is_at_most(
+				    rec, page_get_supremum_rec(page),
+				    max_nodes_deleted)) {
+				return true;
+			}
+
 			/* Delete at leftmost record in a page causes delete
 			& insert at its parent page. After that, the delete
 			might cause btr_compress() and delete record at its
-			parent page. Thus we should consider max 2 deletes. */
-
-			margin = rec_size * 2;
-		} else {
-			ut_ad(lock_intention == BTR_INTENTION_DELETE);
-
-			margin = rec_size;
+			parent page. Thus we should consider max deletes. */
+			margin *= max_nodes_deleted;
 		}
-		/* NOTE: call mach_read_from_4() directly to avoid assertion
-		failure. It is safe because we already have SX latch of the
-		index tree */
+
+		/* Safe because we already have SX latch of the index tree */
 		if (page_get_data_size(page)
-			< margin + BTR_CUR_PAGE_COMPRESS_LIMIT(index)
-		    || (mach_read_from_4(page + FIL_PAGE_NEXT)
-				== FIL_NULL
-			&& mach_read_from_4(page + FIL_PAGE_PREV)
-				== FIL_NULL)) {
+		    < margin + BTR_CUR_PAGE_COMPRESS_LIMIT(index)) {
 			return(true);
 		}
 	}
@@ -2160,9 +2180,9 @@ need_opposite_intention:
 				offsets2 = rec_get_offsets(
 					first_rec, index, offsets2,
 					false, ULINT_UNDEFINED, &heap);
-				cmp_rec_rec_with_match(node_ptr, first_rec,
-					offsets, offsets2, index, FALSE,
-					&matched_fields);
+				cmp_rec_rec(node_ptr, first_rec,
+					    offsets, offsets2, index, false,
+					    &matched_fields);
 
 				if (matched_fields
 				    >= rec_offs_n_fields(offsets) - 1) {
@@ -2178,10 +2198,10 @@ need_opposite_intention:
 					offsets2 = rec_get_offsets(
 						last_rec, index, offsets2,
 						false, ULINT_UNDEFINED, &heap);
-					cmp_rec_rec_with_match(
+					cmp_rec_rec(
 						node_ptr, last_rec,
 						offsets, offsets2, index,
-						FALSE, &matched_fields);
+						false, &matched_fields);
 					if (matched_fields
 					    >= rec_offs_n_fields(offsets) - 1) {
 						detected_same_key_root = true;
@@ -4506,7 +4526,6 @@ btr_cur_optimistic_update(
 	dtuple_t*	new_entry;
 	roll_ptr_t	roll_ptr;
 	ulint		i;
-	ulint		n_ext;
 
 	block = btr_cur_get_block(cursor);
 	page = buf_block_get_frame(block);
@@ -4585,10 +4604,8 @@ any_extern:
 			+ DTUPLE_EST_ALLOC(rec_offs_n_fields(*offsets)));
 	}
 
-	new_entry = row_rec_to_index_entry(rec, index, *offsets,
-					   &n_ext, *heap);
-	/* We checked above that there are no externally stored fields. */
-	ut_a(!n_ext);
+	new_entry = row_rec_to_index_entry(rec, index, *offsets, *heap);
+	ut_ad(!dtuple_get_n_ext(new_entry));
 
 	/* The page containing the clustered index record
 	corresponding to new_entry is latched in mtr.
@@ -4850,7 +4867,6 @@ btr_cur_pessimistic_update(
 	roll_ptr_t	roll_ptr;
 	ibool		was_first;
 	ulint		n_reserved	= 0;
-	ulint		n_ext;
 	ulint		max_ins_size	= 0;
 
 	*offsets = NULL;
@@ -4923,15 +4939,14 @@ btr_cur_pessimistic_update(
 		ut_ad(flags & BTR_NO_LOCKING_FLAG);
 		ut_ad(index->is_instant());
 		new_entry = row_metadata_to_tuple(
-			rec, index, *offsets,
-			&n_ext, entry_heap,
+			rec, index, *offsets, entry_heap,
 			update->info_bits, !thr_get_trx(thr)->in_rollback);
 		ut_ad(new_entry->n_fields
 		      == ulint(index->n_fields)
 		      + update->is_alter_metadata());
 	} else {
 		new_entry = row_rec_to_index_entry(rec, index, *offsets,
-						   &n_ext, entry_heap);
+						   entry_heap);
 	}
 
 	/* The page containing the clustered index record
@@ -4942,7 +4957,6 @@ btr_cur_pessimistic_update(
 	itself.  Thus the following call is safe. */
 	row_upd_index_replace_new_col_vals_index_pos(new_entry, index, update,
 						     entry_heap);
-	const ulint n = new_entry->n_fields;
 	btr_cur_trim(new_entry, index, update, thr);
 
 	/* We have to set appropriate extern storage bits in the new
@@ -4950,10 +4964,6 @@ btr_cur_pessimistic_update(
 
 	ut_ad(!page_is_comp(page) || !rec_get_node_ptr_flag(rec));
 	ut_ad(rec_offs_validate(rec, index, *offsets));
-	if (index->is_primary()) {
-		n_ext += btr_push_update_extern_fields(
-			new_entry, n, update, entry_heap);
-	}
 
 	if ((flags & BTR_NO_UNDO_LOG_FLAG)
 	    && rec_offs_any_extern(*offsets)) {
@@ -4974,6 +4984,8 @@ btr_cur_pessimistic_update(
 			index, rec, page_zip, *offsets, update, true, mtr);
 	}
 
+	ulint n_ext = index->is_primary() ? dtuple_get_n_ext(new_entry) : 0;
+
 	if (page_zip_rec_needs_ext(
 		    rec_get_converted_size(index, new_entry, n_ext),
 		    page_is_comp(page),
@@ -7007,10 +7019,10 @@ btr_estimate_number_of_different_key_vals(
 							   ULINT_UNDEFINED,
 							   &heap);
 
-			cmp_rec_rec_with_match(rec, next_rec,
-					       offsets_rec, offsets_next_rec,
-					       index, stats_null_not_equal,
-					       &matched_fields);
+			cmp_rec_rec(rec, next_rec,
+				    offsets_rec, offsets_next_rec,
+				    index, stats_null_not_equal,
+				    &matched_fields);
 
 			for (j = matched_fields; j < n_cols; j++) {
 				/* We add one if this index record has
@@ -7290,88 +7302,6 @@ btr_cur_unmark_extern_fields(
 	}
 }
 
-/** Flag the data tuple fields that are marked as extern storage in the
-update vector.  We use this function to remember which fields we must
-mark as extern storage in a record inserted for an update.
-@param[in,out]	tuple	clustered index record
-@param[in]	n	number of fields in tuple, before any btr_cur_trim()
-@param[in]	update	update vector
-@param[in,out]	heap	memory heap
-@return number of flagged external columns */
-ulint
-btr_push_update_extern_fields(dtuple_t* tuple, ulint n, const upd_t* update,
-			      mem_heap_t* heap)
-{
-	ulint n_pushed = 0;
-	const upd_field_t* uf = update->fields;
-
-	ut_ad(n >= tuple->n_fields);
-	/* The clustered index record must always contain a
-	PRIMARY KEY and the system columns DB_TRX_ID,DB_ROLL_PTR. */
-	ut_ad(tuple->n_fields > DATA_ROLL_PTR);
-	compile_time_assert(DATA_ROLL_PTR == 2);
-
-	for (ulint un = upd_get_n_fields(update); un--; uf++) {
-		ut_ad(uf->field_no < n);
-
-		if (dfield_is_ext(&uf->new_val)
-		    && uf->field_no < tuple->n_fields) {
-			dfield_t* field = &tuple->fields[uf->field_no];
-
-			if (!dfield_is_ext(field)) {
-				dfield_set_ext(field);
-				n_pushed++;
-			}
-
-			switch (uf->orig_len) {
-				byte*	data;
-				ulint	len;
-				byte*	buf;
-			case 0:
-				break;
-			case BTR_EXTERN_FIELD_REF_SIZE:
-				/* Restore the original locally stored
-				part of the column.  In the undo log,
-				InnoDB writes a longer prefix of externally
-				stored columns, so that column prefixes
-				in secondary indexes can be reconstructed. */
-				dfield_set_data(field,
-						(byte*) dfield_get_data(field)
-						+ dfield_get_len(field)
-						- BTR_EXTERN_FIELD_REF_SIZE,
-						BTR_EXTERN_FIELD_REF_SIZE);
-				dfield_set_ext(field);
-				break;
-			default:
-				/* Reconstruct the original locally
-				stored part of the column.  The data
-				will have to be copied. */
-				ut_a(uf->orig_len > BTR_EXTERN_FIELD_REF_SIZE);
-
-				data = (byte*) dfield_get_data(field);
-				len = dfield_get_len(field);
-
-				buf = (byte*) mem_heap_alloc(heap,
-							     uf->orig_len);
-				/* Copy the locally stored prefix. */
-				memcpy(buf, data,
-				       unsigned(uf->orig_len)
-				       - BTR_EXTERN_FIELD_REF_SIZE);
-				/* Copy the BLOB pointer. */
-				memcpy(buf + unsigned(uf->orig_len)
-				       - BTR_EXTERN_FIELD_REF_SIZE,
-				       data + len - BTR_EXTERN_FIELD_REF_SIZE,
-				       BTR_EXTERN_FIELD_REF_SIZE);
-
-				dfield_set_data(field, buf, uf->orig_len);
-				dfield_set_ext(field);
-			}
-		}
-	}
-
-	return(n_pushed);
-}
-
 /*******************************************************************//**
 Returns the length of a BLOB part stored on the header page.
 @return part length */
diff --git a/storage/innobase/buf/buf0dblwr.cc b/storage/innobase/buf/buf0dblwr.cc
index 791b5614fc2..00d6c1f9ded 100644
--- a/storage/innobase/buf/buf0dblwr.cc
+++ b/storage/innobase/buf/buf0dblwr.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1995, 2017, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2013, 2019, MariaDB Corporation.
+Copyright (c) 2013, 2020, 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
@@ -998,6 +998,7 @@ try_again:
 		int64_t	sig_count = os_event_reset(buf_dblwr->b_event);
 		mutex_exit(&buf_dblwr->mutex);
 
+		os_aio_simulated_wake_handler_threads();
 		os_event_wait_low(buf_dblwr->b_event, sig_count);
 		goto try_again;
 	}
@@ -1124,6 +1125,7 @@ try_again:
 		checkpoint. */
 		int64_t	sig_count = os_event_reset(buf_dblwr->b_event);
 		mutex_exit(&buf_dblwr->mutex);
+		os_aio_simulated_wake_handler_threads();
 
 		os_event_wait_low(buf_dblwr->b_event, sig_count);
 		goto try_again;
diff --git a/storage/innobase/dict/dict0stats.cc b/storage/innobase/dict/dict0stats.cc
index 990a36524cd..c420d7a3c14 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, 2019, MariaDB Corporation.
+Copyright (c) 2015, 2020, 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
@@ -1165,13 +1165,9 @@ dict_stats_analyze_index_level(
 				prev_rec, index, prev_rec_offsets, !level,
 				n_uniq, &heap);
 
-			cmp_rec_rec_with_match(rec,
-					       prev_rec,
-					       rec_offsets,
-					       prev_rec_offsets,
-					       index,
-					       FALSE,
-					       &matched_fields);
+			cmp_rec_rec(prev_rec, rec,
+				    prev_rec_offsets, rec_offsets, index,
+				    false, &matched_fields);
 
 			for (i = matched_fields; i < n_uniq; i++) {
 
@@ -1391,9 +1387,8 @@ dict_stats_scan_page(
 
 		/* check whether rec != next_rec when looking at
 		the first n_prefix fields */
-		cmp_rec_rec_with_match(rec, next_rec,
-				       offsets_rec, offsets_next_rec,
-				       index, FALSE, &matched_fields);
+		cmp_rec_rec(rec, next_rec, offsets_rec, offsets_next_rec,
+			    index, false, &matched_fields);
 
 		if (matched_fields < n_prefix) {
 			/* rec != next_rec, => rec is non-boring */
diff --git a/storage/innobase/gis/gis0rtree.cc b/storage/innobase/gis/gis0rtree.cc
index f54cb66692f..ec6143d05d3 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, 2019, MariaDB Corporation.
+Copyright (c) 2018, 2020, 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
@@ -1438,10 +1438,9 @@ rtr_page_copy_rec_list_end_no_locks(
 			offsets2 = rec_get_offsets(cur_rec, index, offsets2,
 						   is_leaf,
 						   ULINT_UNDEFINED, &heap);
-			cmp = cmp_rec_rec_with_match(cur1_rec, cur_rec,
-						     offsets1, offsets2,
-						     index, FALSE,
-						     &cur_matched_fields);
+			cmp = cmp_rec_rec(cur1_rec, cur_rec,
+					  offsets1, offsets2, index, false,
+					  &cur_matched_fields);
 			if (cmp < 0) {
 				page_cur_move_to_prev(&page_cur);
 				break;
@@ -1553,15 +1552,13 @@ rtr_page_copy_rec_list_start_no_locks(
 
 		while (!page_rec_is_supremum(cur_rec)) {
 			ulint		cur_matched_fields = 0;
-			int		cmp;
 
 			offsets2 = rec_get_offsets(cur_rec, index, offsets2,
 						   is_leaf,
 						   ULINT_UNDEFINED, &heap);
-			cmp = cmp_rec_rec_with_match(cur1_rec, cur_rec,
-						     offsets1, offsets2,
-						     index, FALSE,
-						     &cur_matched_fields);
+			int cmp = cmp_rec_rec(cur1_rec, cur_rec,
+					      offsets1, offsets2, index, false,
+					      &cur_matched_fields);
 			if (cmp < 0) {
 				page_cur_move_to_prev(&page_cur);
 				cur_rec = page_cur_get_rec(&page_cur);
diff --git a/storage/innobase/include/btr0cur.h b/storage/innobase/include/btr0cur.h
index 84286bd2680..5d10d26e025 100644
--- a/storage/innobase/include/btr0cur.h
+++ b/storage/innobase/include/btr0cur.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
-Copyright (c) 1994, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2019, MariaDB Corporation.
+Copyright (c) 1994, 2019, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2017, 2020, 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
@@ -785,18 +785,6 @@ btr_rec_copy_externally_stored_field(
 	ulint*			len,
 	mem_heap_t*		heap);
 
-/** Flag the data tuple fields that are marked as extern storage in the
-update vector.  We use this function to remember which fields we must
-mark as extern storage in a record inserted for an update.
-@param[in,out]	tuple	clustered index record
-@param[in]	n	number of fields in tuple, before any btr_cur_trim()
-@param[in]	update	update vector
-@param[in,out]	heap	memory heap
-@return number of flagged external columns */
-ulint
-btr_push_update_extern_fields(dtuple_t* tuple, ulint n, const upd_t* update,
-			      mem_heap_t* heap)
-	MY_ATTRIBUTE((nonnull));
 /***********************************************************//**
 Sets a secondary index record's delete mark to the given value. This
 function is only used by the insert buffer merge mechanism. */
diff --git a/storage/innobase/include/dyn0buf.h b/storage/innobase/include/dyn0buf.h
index b5da367bae1..f66c7e3d405 100644
--- a/storage/innobase/include/dyn0buf.h
+++ b/storage/innobase/include/dyn0buf.h
@@ -303,8 +303,7 @@ public:
 #ifdef UNIV_DEBUG
 		ulint	total_size = 0;
 
-		for (typename list_t::iterator it = m_list.begin(),
-					       end = m_list.end();
+		for (list_t::iterator it = m_list.begin(), end = m_list.end();
 		     it != end; ++it) {
 			total_size += it->used();
 		}
@@ -320,8 +319,7 @@ public:
 	template <typename Functor>
 	bool for_each_block(Functor& functor) const
 	{
-		for (typename list_t::iterator it = m_list.begin(),
-					       end = m_list.end();
+		for (list_t::iterator it = m_list.begin(), end = m_list.end();
 		     it != end; ++it) {
 
 			if (!functor(&*it)) {
@@ -338,8 +336,8 @@ public:
 	template <typename Functor>
 	bool for_each_block_in_reverse(Functor& functor) const
 	{
-		for (typename list_t::reverse_iterator it = m_list.rbegin(),
-						       end = m_list.rend();
+		for (list_t::reverse_iterator it = m_list.rbegin(),
+					      end = m_list.rend();
 		     it != end; ++it) {
 
 			if (!functor(&*it)) {
@@ -356,8 +354,8 @@ public:
 	template <typename Functor>
 	bool for_each_block_in_reverse(const Functor& functor) const
 	{
-		for (typename list_t::reverse_iterator it = m_list.rbegin(),
-						       end = m_list.rend();
+		for (list_t::reverse_iterator it = m_list.rbegin(),
+					      end = m_list.rend();
 		     it != end; ++it) {
 
 			if (!functor(&*it)) {
@@ -425,8 +423,7 @@ private:
 	{
 		ut_ad(!m_list.empty());
 
-		for (typename list_t::iterator it = m_list.begin(),
-					       end = m_list.end();
+		for (list_t::iterator it = m_list.begin(), end = m_list.end();
 		     it != end; ++it) {
 
 			if (pos < it->used()) {
diff --git a/storage/innobase/include/page0page.h b/storage/innobase/include/page0page.h
index 54586b3ce3b..31a60bcb4e5 100644
--- a/storage/innobase/include/page0page.h
+++ b/storage/innobase/include/page0page.h
@@ -1,6 +1,6 @@
 /*****************************************************************************
-Copyright (c) 1994, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2013, 2019, MariaDB Corporation.
+Copyright (c) 1994, 2019, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2013, 2020, 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
@@ -852,6 +852,22 @@ page_rec_is_last(
 	MY_ATTRIBUTE((warn_unused_result));
 
 /************************************************************//**
+true if distance between the records (measured in number of times we have to
+move to the next record) is at most the specified value
+@param[in]	left_rec	lefter record
+@param[in]	right_rec	righter record
+@param[in]	val		specified value to compare
+@return true if the distance is smaller than the value */
+UNIV_INLINE
+bool
+page_rec_distance_is_at_most(
+/*=========================*/
+	const rec_t*	left_rec,
+	const rec_t*	right_rec,
+	ulint		val)
+	MY_ATTRIBUTE((warn_unused_result));
+
+/************************************************************//**
 true if the record is the second last user record on a page.
 @return true if the second last user record */
 UNIV_INLINE
diff --git a/storage/innobase/include/page0page.ic b/storage/innobase/include/page0page.ic
index 21ab45427ff..28ee193c6e5 100644
--- a/storage/innobase/include/page0page.ic
+++ b/storage/innobase/include/page0page.ic
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
-Copyright (c) 1994, 2015, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2016, 2019, MariaDB Corporation.
+Copyright (c) 1994, 2019, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2016, 2020, 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
@@ -351,6 +351,26 @@ page_rec_is_last(
 }
 
 /************************************************************//**
+true if distance between the records (measured in number of times we have to
+move to the next record) is at most the specified value */
+UNIV_INLINE
+bool
+page_rec_distance_is_at_most(
+/*=========================*/
+	const rec_t*	left_rec,
+	const rec_t*	right_rec,
+	ulint		val)
+{
+	for (ulint i = 0; i <= val; i++) {
+		if (left_rec == right_rec) {
+			return (true);
+		}
+		left_rec = page_rec_get_next_const(left_rec);
+	}
+	return (false);
+}
+
+/************************************************************//**
 true if the record is the second last user record on a page.
 @return true if the second last user record */
 UNIV_INLINE
diff --git a/storage/innobase/include/rem0cmp.h b/storage/innobase/include/rem0cmp.h
index 0877c7b5b6a..af1b145b0d9 100644
--- a/storage/innobase/include/rem0cmp.h
+++ b/storage/innobase/include/rem0cmp.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1994, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, MariaDB Corporation.
+Copyright (c) 2017, 2020, 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
@@ -80,7 +80,7 @@ cmp_dfield_dfield(
 
 /** Compare a GIS data tuple to a physical record.
 @param[in] dtuple data tuple
-@param[in] rec B-tree record
+@param[in] rec R-tree record
 @param[in] offsets rec_get_offsets(rec)
 @param[in] mode compare mode
 @retval negative if dtuple is less than rec */
@@ -190,43 +190,23 @@ cmp_rec_rec_simple(
 					duplicate key value if applicable,
 					or NULL */
 	MY_ATTRIBUTE((nonnull(1,2,3,4), warn_unused_result));
-/** Compare two B-tree records.
-@param[in] rec1 B-tree record
-@param[in] rec2 B-tree record
-@param[in] offsets1 rec_get_offsets(rec1, index)
-@param[in] offsets2 rec_get_offsets(rec2, index)
-@param[in] index B-tree index
-@param[in] nulls_unequal true if this is for index cardinality
-statistics estimation, and innodb_stats_method=nulls_unequal
-or innodb_stats_method=nulls_ignored
-@param[out] matched_fields number of completely matched fields
-within the first field not completely matched
-@return the comparison result
-@retval 0 if rec1 is equal to rec2
-@retval negative if rec1 is less than rec2
-@retval positive if rec2 is greater than rec2 */
-int
-cmp_rec_rec_with_match(
-	const rec_t*		rec1,
-	const rec_t*		rec2,
-	const offset_t*		offsets1,
-	const offset_t*		offsets2,
-	const dict_index_t*	index,
-	bool			nulls_unequal,
-	ulint*			matched_fields);
 
-/** Compare two B-tree records.
+/** Compare two B-tree or R-tree records.
 Only the common first fields are compared, and externally stored field
 are treated as equal.
-@param[in]	rec1		B-tree record
-@param[in]	rec2		B-tree record
+@param[in]	rec1		record (possibly not on an index page)
+@param[in]	rec2		B-tree or R-tree record in an index page
 @param[in]	offsets1	rec_get_offsets(rec1, index)
 @param[in]	offsets2	rec_get_offsets(rec2, index)
+@param[in]	nulls_unequal	true if this is for index cardinality
+				statistics estimation with
+				innodb_stats_method=nulls_unequal
+				or innodb_stats_method=nulls_ignored
 @param[out]	matched_fields	number of completely matched fields
 				within the first field not completely matched
-@return positive, 0, negative if rec1 is greater, equal, less, than rec2,
-respectively */
-UNIV_INLINE
+@retval 0 if rec1 is equal to rec2
+@retval negative if rec1 is less than rec2
+@retval positive if rec1 is greater than rec2 */
 int
 cmp_rec_rec(
 	const rec_t*		rec1,
@@ -234,7 +214,9 @@ cmp_rec_rec(
 	const offset_t*		offsets1,
 	const offset_t*		offsets2,
 	const dict_index_t*	index,
-	ulint*			matched_fields = NULL);
+	bool			nulls_unequal = false,
+	ulint*			matched_fields = NULL)
+	MY_ATTRIBUTE((nonnull(1,2,3,4,5)));
 
 /** Compare two data fields.
 @param[in] dfield1 data field
diff --git a/storage/innobase/include/rem0cmp.ic b/storage/innobase/include/rem0cmp.ic
index 5ac3838f244..4230543615a 100644
--- a/storage/innobase/include/rem0cmp.ic
+++ b/storage/innobase/include/rem0cmp.ic
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1994, 2014, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2020, 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
@@ -52,40 +53,6 @@ cmp_dfield_dfield(
 			     dfield_get_len(dfield2)));
 }
 
-/** Compare two B-tree records.
-Only the common first fields are compared, and externally stored field
-are treated as equal.
-@param[in]	rec1		B-tree record
-@param[in]	rec2		B-tree record
-@param[in]	offsets1	rec_get_offsets(rec1, index)
-@param[in]	offsets2	rec_get_offsets(rec2, index)
-@param[out]	matched_fields	number of completely matched fields
-				within the first field not completely matched
-@return positive, 0, negative if rec1 is greater, equal, less, than rec2,
-respectively */
-UNIV_INLINE
-int
-cmp_rec_rec(
-	const rec_t*		rec1,
-	const rec_t*		rec2,
-	const offset_t*		offsets1,
-	const offset_t*		offsets2,
-	const dict_index_t*	index,
-	ulint*			matched_fields)
-{
-	ulint	match_f;
-	int	ret;
-
-	ret = cmp_rec_rec_with_match(
-		rec1, rec2, offsets1, offsets2, index, false, &match_f);
-
-	if (matched_fields != NULL) {
-		*matched_fields = match_f;
-	}
-
-	return(ret);
-}
-
 /** Compare two data fields.
 @param[in] dfield1 data field
 @param[in] dfield2 data field
diff --git a/storage/innobase/include/rem0rec.ic b/storage/innobase/include/rem0rec.ic
index 56727f40e23..c440850cf13 100644
--- a/storage/innobase/include/rem0rec.ic
+++ b/storage/innobase/include/rem0rec.ic
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
-Copyright (c) 1994, 2015, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2019, MariaDB Corporation.
+Copyright (c) 1994, 2019, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2017, 2020, 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
@@ -1390,6 +1390,7 @@ rec_get_converted_size(
 
 	data_size = dtuple_get_data_size(dtuple, 0);
 
+	ut_ad(n_ext == dtuple_get_n_ext(dtuple));
 	extra_size = rec_get_converted_extra_size(
 		data_size, dtuple_get_n_fields(dtuple), n_ext);
 
diff --git a/storage/innobase/include/row0row.h b/storage/innobase/include/row0row.h
index 264cae52832..be451751f56 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, 2019, MariaDB Corporation.
+Copyright (c) 2016, 2020, 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
@@ -208,8 +208,6 @@ row_rec_to_index_entry_low(
 	const rec_t*		rec,	/*!< in: record in the index */
 	const dict_index_t*	index,	/*!< in: index */
 	const offset_t*		offsets,/*!< in: rec_get_offsets(rec, index) */
-	ulint*			n_ext,	/*!< out: number of externally
-					stored columns */
 	mem_heap_t*		heap)	/*!< in: memory heap from which
 					the memory needed is allocated */
 	MY_ATTRIBUTE((warn_unused_result));
@@ -223,8 +221,6 @@ row_rec_to_index_entry(
 	const rec_t*		rec,	/*!< in: record in the index */
 	const dict_index_t*	index,	/*!< in: index */
 	const offset_t*		offsets,/*!< in/out: rec_get_offsets(rec) */
-	ulint*			n_ext,	/*!< out: number of externally
-					stored columns */
 	mem_heap_t*		heap)	/*!< in: memory heap from which
 					the memory needed is allocated */
 	MY_ATTRIBUTE((warn_unused_result));
@@ -233,7 +229,6 @@ row_rec_to_index_entry(
 @param[in]	rec		metadata record
 @param[in]	index		clustered index after instant ALTER TABLE
 @param[in]	offsets		rec_get_offsets(rec)
-@param[out]	n_ext		number of externally stored fields
 @param[in,out]	heap		memory heap for allocations
 @param[in]	info_bits	the info_bits after an update
 @param[in]	pad		whether to pad to index->n_fields */
@@ -242,7 +237,6 @@ row_metadata_to_tuple(
 	const rec_t*		rec,
 	const dict_index_t*	index,
 	const offset_t*		offsets,
-	ulint*			n_ext,
 	mem_heap_t*		heap,
 	ulint			info_bits,
 	bool			pad)
diff --git a/storage/innobase/include/univ.i b/storage/innobase/include/univ.i
index 644a9484af4..e9d427e04c0 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, 2019, MariaDB Corporation.
+Copyright (c) 2013, 2020, MariaDB Corporation.
 Copyright (c) 2008, Google Inc.
 
 Portions of this file contain modifications contributed and copyrighted by
diff --git a/storage/innobase/os/os0file.cc b/storage/innobase/os/os0file.cc
index 95c31523325..b1c2a3925ee 100644
--- a/storage/innobase/os/os0file.cc
+++ b/storage/innobase/os/os0file.cc
@@ -1,8 +1,8 @@
 /***********************************************************************
 
-Copyright (c) 1995, 2017, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 1995, 2019, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2009, Percona Inc.
-Copyright (c) 2013, 2019, MariaDB Corporation.
+Copyright (c) 2013, 2020, MariaDB Corporation.
 
 Portions of this file contain modifications contributed and copyrighted
 by Percona Inc.. Those modifications are
@@ -1357,6 +1357,12 @@ os_file_get_parent_dir(
 		return(NULL);
 	}
 
+	if (last_slash - path < 0) {
+		/* Sanity check, it prevents gcc from trying to handle this case which
+		 * results in warnings for some optimized builds */
+		return (NULL);
+	}
+
 	/* Non-trivial directory component */
 
 	return(mem_strdupl(path, ulint(last_slash - path)));
diff --git a/storage/innobase/rem/rem0cmp.cc b/storage/innobase/rem/rem0cmp.cc
index b9be9c05073..34ae5b08bab 100644
--- a/storage/innobase/rem/rem0cmp.cc
+++ b/storage/innobase/rem/rem0cmp.cc
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
-Copyright (c) 1994, 2016, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 1994, 2019, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2020, 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
@@ -534,7 +535,7 @@ cmp_data(
 
 /** Compare a GIS data tuple to a physical record.
 @param[in] dtuple data tuple
-@param[in] rec B-tree record
+@param[in] rec R-tree record
 @param[in] offsets rec_get_offsets(rec)
 @param[in] mode compare mode
 @retval negative if dtuple is less than rec */
@@ -1096,23 +1097,24 @@ cmp_rec_rec_simple(
 	return(0);
 }
 
-/** Compare two B-tree records.
-@param[in] rec1 B-tree record
-@param[in] rec2 B-tree record
-@param[in] offsets1 rec_get_offsets(rec1, index)
-@param[in] offsets2 rec_get_offsets(rec2, index)
-@param[in] index B-tree index
-@param[in] nulls_unequal true if this is for index cardinality
-statistics estimation, and innodb_stats_method=nulls_unequal
-or innodb_stats_method=nulls_ignored
-@param[out] matched_fields number of completely matched fields
-within the first field not completely matched
-@return the comparison result
+/** Compare two B-tree or R-tree records.
+Only the common first fields are compared, and externally stored field
+are treated as equal.
+@param[in]	rec1		record (possibly not on an index page)
+@param[in]	rec2		B-tree or R-tree record in an index page
+@param[in]	offsets1	rec_get_offsets(rec1, index)
+@param[in]	offsets2	rec_get_offsets(rec2, index)
+@param[in]	nulls_unequal	true if this is for index cardinality
+				statistics estimation with
+				innodb_stats_method=nulls_unequal
+				or innodb_stats_method=nulls_ignored
+@param[out]	matched_fields	number of completely matched fields
+				within the first field not completely matched
 @retval 0 if rec1 is equal to rec2
 @retval negative if rec1 is less than rec2
-@retval positive if rec2 is greater than rec2 */
+@retval positive if rec1 is greater than rec2 */
 int
-cmp_rec_rec_with_match(
+cmp_rec_rec(
 	const rec_t*		rec1,
 	const rec_t*		rec2,
 	const offset_t*		offsets1,
@@ -1121,17 +1123,14 @@ cmp_rec_rec_with_match(
 	bool			nulls_unequal,
 	ulint*			matched_fields)
 {
-	ulint		rec1_n_fields;	/* the number of fields in rec */
 	ulint		rec1_f_len;	/* length of current field in rec */
 	const byte*	rec1_b_ptr;	/* pointer to the current byte
 					in rec field */
-	ulint		rec2_n_fields;	/* the number of fields in rec */
 	ulint		rec2_f_len;	/* length of current field in rec */
 	const byte*	rec2_b_ptr;	/* pointer to the current byte
 					in rec field */
 	ulint		cur_field = 0;	/* current field number */
 	int		ret = 0;	/* return value */
-	ulint		comp;
 
 	ut_ad(rec1 != NULL);
 	ut_ad(rec2 != NULL);
@@ -1139,10 +1138,12 @@ cmp_rec_rec_with_match(
 	ut_ad(rec_offs_validate(rec1, index, offsets1));
 	ut_ad(rec_offs_validate(rec2, index, offsets2));
 	ut_ad(rec_offs_comp(offsets1) == rec_offs_comp(offsets2));
+	ut_ad(fil_page_index_page_check(page_align(rec2)));
+	ut_ad(!!dict_index_is_spatial(index)
+	      == (fil_page_get_type(page_align(rec2)) == FIL_PAGE_RTREE));
 
-	comp = rec_offs_comp(offsets1);
-	rec1_n_fields = rec_offs_n_fields(offsets1);
-	rec2_n_fields = rec_offs_n_fields(offsets2);
+	ulint comp = rec_offs_comp(offsets1);
+	ulint n_fields;
 
 	/* Test if rec is the predefined minimum record */
 	if (UNIV_UNLIKELY(rec_get_info_bits(rec1, comp)
@@ -1158,37 +1159,41 @@ cmp_rec_rec_with_match(
 		goto order_resolved;
 	}
 
-	/* Match fields in a loop */
+	/* For non-leaf spatial index records, the
+	dict_index_get_n_unique_in_tree() does include the child page
+	number, because spatial index node pointers only contain
+	the MBR (minimum bounding rectangle) and the child page number.
 
-	for (; cur_field < rec1_n_fields && cur_field < rec2_n_fields;
-	     cur_field++) {
+	For B-tree node pointers, the key alone (secondary index
+	columns and PRIMARY KEY columns) must be unique, and there is
+	no need to compare the child page number. */
+	n_fields = std::min(rec_offs_n_fields(offsets1),
+			    rec_offs_n_fields(offsets2));
+	n_fields = std::min(n_fields, dict_index_get_n_unique_in_tree(index));
 
+	for (; cur_field < n_fields; cur_field++) {
 		ulint	mtype;
 		ulint	prtype;
 
-		/* If this is node-ptr records then avoid comparing node-ptr
-		field. Only key field needs to be compared. */
-		if (cur_field == dict_index_get_n_unique_in_tree(index)) {
-			break;
-		}
-
-		if (dict_index_is_ibuf(index)) {
+		if (UNIV_UNLIKELY(dict_index_is_ibuf(index))) {
 			/* This is for the insert buffer B-tree. */
 			mtype = DATA_BINARY;
 			prtype = 0;
 		} else {
-			const dict_col_t*	col;
-
-			col	= dict_index_get_nth_col(index, cur_field);
-
+			const dict_col_t* col = dict_index_get_nth_col(
+				index, cur_field);
 			mtype = col->mtype;
 			prtype = col->prtype;
 
-			/* If the index is spatial index, we mark the
-			prtype of the first field as MBR field. */
-			if (cur_field == 0 && dict_index_is_spatial(index)) {
+			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;
 			}
 		}
 
@@ -1226,8 +1231,10 @@ cmp_rec_rec_with_match(
 	to the common fields */
 	ut_ad(ret == 0);
 order_resolved:
-	*matched_fields = cur_field;
-	return(ret);
+	if (matched_fields) {
+		*matched_fields = cur_field;
+	}
+	return ret;
 }
 
 #ifdef UNIV_COMPILE_TEST_FUNCS
diff --git a/storage/innobase/row/row0ftsort.cc b/storage/innobase/row/row0ftsort.cc
index 38ba39bea98..7e3b70bfadb 100644
--- a/storage/innobase/row/row0ftsort.cc
+++ b/storage/innobase/row/row0ftsort.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2010, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2015, 2019, MariaDB Corporation.
+Copyright (c) 2015, 2020, 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
@@ -1722,7 +1722,6 @@ row_fts_merge_insert(
 	corresponding FTS index auxiliary tables */
 	for (;;) {
 		dtuple_t*	dtuple;
-		ulint		n_ext;
 		int		min_rec = 0;
 
 		if (fts_sort_pll_degree <= 2) {
@@ -1765,7 +1764,7 @@ row_fts_merge_insert(
 		}
 
 		dtuple = row_rec_to_index_entry_low(
-			mrec[min_rec], index, offsets[min_rec], &n_ext,
+			mrec[min_rec], index, offsets[min_rec],
 			tuple_heap);
 
 		row_fts_insert_tuple(
diff --git a/storage/innobase/row/row0import.cc b/storage/innobase/row/row0import.cc
index 9adc5da2b8b..d161a8134aa 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, 2019, MariaDB Corporation.
+Copyright (c) 2015, 2020, 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
@@ -1157,60 +1157,82 @@ row_import::match_table_columns(
 
 			if (cfg_col->prtype != col->prtype) {
 				ib_errf(thd,
-					 IB_LOG_LEVEL_ERROR,
-					 ER_TABLE_SCHEMA_MISMATCH,
-					 "Column %s precise type mismatch.",
-					 col_name);
+					IB_LOG_LEVEL_ERROR,
+					ER_TABLE_SCHEMA_MISMATCH,
+					"Column %s precise type mismatch,"
+					" it's 0X%X in the table and 0X%X"
+					" in the tablespace meta file",
+					col_name, col->prtype, cfg_col->prtype);
 				err = DB_ERROR;
 			}
 
 			if (cfg_col->mtype != col->mtype) {
 				ib_errf(thd,
-					 IB_LOG_LEVEL_ERROR,
-					 ER_TABLE_SCHEMA_MISMATCH,
-					 "Column %s main type mismatch.",
-					 col_name);
+					IB_LOG_LEVEL_ERROR,
+					ER_TABLE_SCHEMA_MISMATCH,
+					"Column %s main type mismatch,"
+					" it's 0X%X in the table and 0X%X"
+					" in the tablespace meta file",
+					col_name, col->mtype, cfg_col->mtype);
 				err = DB_ERROR;
 			}
 
 			if (cfg_col->len != col->len) {
 				ib_errf(thd,
-					 IB_LOG_LEVEL_ERROR,
-					 ER_TABLE_SCHEMA_MISMATCH,
-					 "Column %s length mismatch.",
-					 col_name);
+					IB_LOG_LEVEL_ERROR,
+					ER_TABLE_SCHEMA_MISMATCH,
+					"Column %s length mismatch,"
+					" it's %u in the table and %u"
+					" in the tablespace meta file",
+					col_name, col->len, cfg_col->len);
 				err = DB_ERROR;
 			}
 
 			if (cfg_col->mbminlen != col->mbminlen
 			    || cfg_col->mbmaxlen != col->mbmaxlen) {
 				ib_errf(thd,
-					 IB_LOG_LEVEL_ERROR,
-					 ER_TABLE_SCHEMA_MISMATCH,
-					 "Column %s multi-byte len mismatch.",
-					 col_name);
+					IB_LOG_LEVEL_ERROR,
+					ER_TABLE_SCHEMA_MISMATCH,
+					"Column %s multi-byte len mismatch,"
+					" it's %u-%u in the table and %u-%u"
+					" in the tablespace meta file",
+					col_name, col->mbminlen, col->mbmaxlen,
+					cfg_col->mbminlen, cfg_col->mbmaxlen);
 				err = DB_ERROR;
 			}
 
 			if (cfg_col->ind != col->ind) {
+				ib_errf(thd,
+					IB_LOG_LEVEL_ERROR,
+					ER_TABLE_SCHEMA_MISMATCH,
+					"Column %s position mismatch,"
+					" it's %u in the table and %u"
+					" in the tablespace meta file",
+					col_name, col->ind, cfg_col->ind);
 				err = DB_ERROR;
 			}
 
 			if (cfg_col->ord_part != col->ord_part) {
 				ib_errf(thd,
-					 IB_LOG_LEVEL_ERROR,
-					 ER_TABLE_SCHEMA_MISMATCH,
-					 "Column %s ordering mismatch.",
-					 col_name);
+					IB_LOG_LEVEL_ERROR,
+					ER_TABLE_SCHEMA_MISMATCH,
+					"Column %s ordering mismatch,"
+					" it's %u in the table and %u"
+					" in the tablespace meta file",
+					col_name, col->ord_part,
+					cfg_col->ord_part);
 				err = DB_ERROR;
 			}
 
 			if (cfg_col->max_prefix != col->max_prefix) {
 				ib_errf(thd,
-					 IB_LOG_LEVEL_ERROR,
-					 ER_TABLE_SCHEMA_MISMATCH,
-					 "Column %s max prefix mismatch.",
-					 col_name);
+					IB_LOG_LEVEL_ERROR,
+					ER_TABLE_SCHEMA_MISMATCH,
+					"Column %s max prefix mismatch"
+					" it's %u in the table and %u"
+					" in the tablespace meta file",
+					col_name, col->max_prefix,
+					cfg_col->max_prefix);
 				err = DB_ERROR;
 			}
 		}
@@ -1509,13 +1531,70 @@ IndexPurge::next() UNIV_NOTHROW
 	mtr_set_log_mode(&m_mtr, MTR_LOG_NO_REDO);
 
 	btr_pcur_restore_position(BTR_MODIFY_LEAF, &m_pcur, &m_mtr);
+	/* The following is based on btr_pcur_move_to_next_user_rec(). */
+	m_pcur.old_stored = false;
+	ut_ad(m_pcur.latch_mode == BTR_MODIFY_LEAF);
+	do {
+		if (btr_pcur_is_after_last_on_page(&m_pcur)) {
+			if (btr_pcur_is_after_last_in_tree(&m_pcur)) {
+				return DB_END_OF_INDEX;
+			}
 
-	if (!btr_pcur_move_to_next_user_rec(&m_pcur, &m_mtr)) {
+			buf_block_t* block = btr_pcur_get_block(&m_pcur);
+			uint32_t next_page = btr_page_get_next(block->frame);
 
-		return(DB_END_OF_INDEX);
-	}
+			/* MDEV-13542 FIXME: Make these checks part of
+			btr_pcur_move_to_next_page(), and introduce a
+			return status that will be checked in all callers! */
+			switch (next_page) {
+			default:
+				if (next_page != block->page.id.page_no()) {
+					break;
+				}
+				/* MDEV-20931 FIXME: Check that
+				next_page is within the tablespace
+				bounds! Also check that it is not a
+				change buffer bitmap page. */
+				/* fall through */
+			case 0:
+			case 1:
+			case FIL_NULL:
+				return DB_CORRUPTION;
+			}
 
-	return(DB_SUCCESS);
+			dict_index_t* index = m_pcur.btr_cur.index;
+			buf_block_t* next_block = btr_block_get(
+				page_id_t(block->page.id.space(), next_page),
+				block->zip_size(), BTR_MODIFY_LEAF, index,
+				&m_mtr);
+
+			if (UNIV_UNLIKELY(!next_block
+					  || !fil_page_index_page_check(
+						  next_block->frame)
+					  || !!dict_index_is_spatial(index)
+					  != (fil_page_get_type(
+						      next_block->frame)
+					      == FIL_PAGE_RTREE)
+					  || page_is_comp(next_block->frame)
+					  != page_is_comp(block->frame)
+					  || btr_page_get_prev(
+						  next_block->frame)
+					  != block->page.id.page_no())) {
+				return DB_CORRUPTION;
+			}
+
+			btr_leaf_page_release(block, BTR_MODIFY_LEAF, &m_mtr);
+
+			page_cur_set_before_first(next_block,
+						  &m_pcur.btr_cur.page_cur);
+
+			ut_d(page_check_dir(next_block->frame));
+		} else {
+			btr_pcur_move_to_next_on_page(&m_pcur);
+		}
+	} while (!btr_pcur_is_on_user_rec(&m_pcur));
+
+	return DB_SUCCESS;
 }
 
 /**
diff --git a/storage/innobase/row/row0log.cc b/storage/innobase/row/row0log.cc
index 56328349e1e..fa50ff80e55 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, 2019, MariaDB Corporation.
+Copyright (c) 2017, 2020, 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
@@ -3562,7 +3562,6 @@ row_log_apply_op(
 	enum row_op	op;
 	ulint		extra_size;
 	ulint		data_size;
-	ulint		n_ext;
 	dtuple_t*	entry;
 	trx_id_t	trx_id;
 
@@ -3640,10 +3639,10 @@ corrupted:
 	}
 
 	entry = row_rec_to_index_entry_low(
-		mrec - data_size, index, offsets, &n_ext, heap);
+		mrec - data_size, index, offsets, heap);
 	/* Online index creation is only implemented for secondary
 	indexes, which never contain off-page columns. */
-	ut_ad(n_ext == 0);
+	ut_ad(dtuple_get_n_ext(entry) == 0);
 
 	row_log_apply_op_low(index, dup, error, offsets_heap,
 			     has_index_lock, op, trx_id, entry);
diff --git a/storage/innobase/row/row0merge.cc b/storage/innobase/row/row0merge.cc
index 8b3831f08af..afa692fa139 100644
--- a/storage/innobase/row/row0merge.cc
+++ b/storage/innobase/row/row0merge.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2005, 2017, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2014, 2019, MariaDB Corporation.
+Copyright (c) 2014, 2020, 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
@@ -3535,7 +3535,6 @@ row_merge_insert_index_tuples(
 	double			curr_progress = 0;
 	dict_index_t*		old_index = NULL;
 	const mrec_t*		mrec  = NULL;
-	ulint			n_ext = 0;
 	mtr_t			mtr;
 
 
@@ -3601,8 +3600,6 @@ row_merge_insert_index_tuples(
 			row buffer to data tuple record */
 			row_merge_mtuple_to_dtuple(
 				index, dtuple, &row_buf->tuples[n_rows]);
-
-			n_ext = dtuple_get_n_ext(dtuple);
 			n_rows++;
 			/* BLOB pointers must be copied from dtuple */
 			mrec = NULL;
@@ -3621,7 +3618,7 @@ row_merge_insert_index_tuples(
 			}
 
 			dtuple = row_rec_to_index_entry_low(
-				mrec, index, offsets, &n_ext, tuple_heap);
+				mrec, index, offsets, tuple_heap);
 		}
 
 		old_index	= dict_table_get_first_index(old_table);
@@ -3634,10 +3631,7 @@ row_merge_insert_index_tuples(
 			}
 		}
 
-		if (!n_ext) {
-			/* There are no externally stored columns. */
-		} else {
-			ut_ad(dict_index_is_clust(index));
+		if (dict_index_is_clust(index) && dtuple_get_n_ext(dtuple)) {
 			/* Off-page columns can be fetched safely
 			when concurrent modifications to the table
 			are disabled. (Purge can process delete-marked
diff --git a/storage/innobase/row/row0mysql.cc b/storage/innobase/row/row0mysql.cc
index 86ef45167a4..bcc877d3d1f 100644
--- a/storage/innobase/row/row0mysql.cc
+++ b/storage/innobase/row/row0mysql.cc
@@ -4675,7 +4675,6 @@ row_scan_index_for_mysql(
 	ulint		i;
 	ulint		cnt;
 	mem_heap_t*	heap		= NULL;
-	ulint		n_ext;
 	offset_t	offsets_[REC_OFFS_NORMAL_SIZE];
 	offset_t*	offsets;
 	rec_offs_init(offsets_);
@@ -4817,7 +4816,7 @@ not_ok:
 		mem_heap_empty(heap);
 
 		prev_entry = row_rec_to_index_entry(
-			rec, index, offsets, &n_ext, heap);
+			rec, index, offsets, heap);
 
 		if (UNIV_LIKELY_NULL(tmp_heap)) {
 			mem_heap_free(tmp_heap);
diff --git a/storage/innobase/row/row0row.cc b/storage/innobase/row/row0row.cc
index 4e901346580..83add52dd88 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, 2019, MariaDB Corporation.
+Copyright (c) 2018, 2020, 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
@@ -722,7 +722,6 @@ row_rec_to_index_entry_impl(
 	const rec_t*		rec,
 	const dict_index_t*	index,
 	const offset_t*		offsets,
-	ulint*			n_ext,
 	mem_heap_t*		heap,
 	ulint			info_bits = 0,
 	bool			pad = false)
@@ -738,8 +737,6 @@ row_rec_to_index_entry_impl(
 	/* Because this function may be invoked by row0merge.cc
 	on a record whose header is in different format, the check
 	rec_offs_validate(rec, index, offsets) must be avoided here. */
-	ut_ad(n_ext);
-	*n_ext = 0;
 
 	const bool got = mblob == 2 && rec_is_alter_metadata(rec, *index);
 	ulint rec_len = rec_offs_n_fields(offsets);
@@ -790,7 +787,6 @@ row_rec_to_index_entry_impl(
 
 		if (rec_offs_nth_extern(offsets, i)) {
 			dfield_set_ext(dfield);
-			++*n_ext;
 		}
 	}
 
@@ -833,7 +829,6 @@ init_metadata:
 		ut_ad(len == FIELD_REF_SIZE);
 		dfield_set_data(dfield, field, len);
 		dfield_set_ext(dfield++);
-		++*n_ext;
 copy_user_fields:
 		for (; i < rec_len; i++, dfield++) {
 			dict_col_copy_type(dict_index_get_nth_col(index, j++),
@@ -851,7 +846,6 @@ copy_user_fields:
 
 			if (rec_offs_nth_extern(offsets, i)) {
 				dfield_set_ext(dfield);
-				++*n_ext;
 			}
 		}
 	}
@@ -870,18 +864,15 @@ copy_user_fields:
 @param[in]	rec	index record
 @param[in]	index	index
 @param[in]	offsets	rec_get_offsets(rec, index)
-@param[out]	n_ext	number of externally stored columns
 @param[in,out]	heap	memory heap for allocations */
 dtuple_t*
 row_rec_to_index_entry_low(
 	const rec_t*		rec,
 	const dict_index_t*	index,
 	const offset_t*		offsets,
-	ulint*			n_ext,
 	mem_heap_t*		heap)
 {
-	return row_rec_to_index_entry_impl<false>(
-		rec, index, offsets, n_ext, heap);
+	return row_rec_to_index_entry_impl<false>(rec, index, offsets, heap);
 }
 
 /*******************************************************************//**
@@ -894,8 +885,6 @@ row_rec_to_index_entry(
 	const rec_t*		rec,	/*!< in: record in the index */
 	const dict_index_t*	index,	/*!< in: index */
 	const offset_t*		offsets,/*!< in: rec_get_offsets(rec) */
-	ulint*			n_ext,	/*!< out: number of externally
-					stored columns */
 	mem_heap_t*		heap)	/*!< in: memory heap from which
 					the memory needed is allocated */
 {
@@ -915,9 +904,9 @@ row_rec_to_index_entry(
 
 	dtuple_t* entry = rec_is_alter_metadata(copy_rec, *index)
 		? row_rec_to_index_entry_impl<true,1>(
-			copy_rec, index, offsets, n_ext, heap)
+			copy_rec, index, offsets, heap)
 		: row_rec_to_index_entry_impl<true>(
-			copy_rec, index, offsets, n_ext, heap);
+			copy_rec, index, offsets, heap);
 
 	rec_offs_make_valid(rec, index, true,
 			    const_cast<offset_t*>(offsets));
@@ -932,7 +921,6 @@ row_rec_to_index_entry(
 @param[in]	rec		metadata record
 @param[in]	index		clustered index after instant ALTER TABLE
 @param[in]	offsets		rec_get_offsets(rec)
-@param[out]	n_ext		number of externally stored fields
 @param[in,out]	heap		memory heap for allocations
 @param[in]	info_bits	the info_bits after an update
 @param[in]	pad		whether to pad to index->n_fields */
@@ -941,7 +929,6 @@ row_metadata_to_tuple(
 	const rec_t*		rec,
 	const dict_index_t*	index,
 	const offset_t*		offsets,
-	ulint*			n_ext,
 	mem_heap_t*		heap,
 	ulint			info_bits,
 	bool			pad)
@@ -962,9 +949,9 @@ row_metadata_to_tuple(
 	dtuple_t* entry = info_bits == REC_INFO_METADATA_ALTER
 		|| rec_is_alter_metadata(copy_rec, *index)
 		? row_rec_to_index_entry_impl<true,2>(
-			copy_rec, index, offsets, n_ext, heap, info_bits, pad)
+			copy_rec, index, offsets, heap, info_bits, pad)
 		: row_rec_to_index_entry_impl<true>(
-			copy_rec, index, offsets, n_ext, heap);
+			copy_rec, index, offsets, heap);
 
 	rec_offs_make_valid(rec, index, true,
 			    const_cast<offset_t*>(offsets));
diff --git a/storage/innobase/row/row0umod.cc b/storage/innobase/row/row0umod.cc
index 5c318f34245..e028e0ccb56 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, 2019, MariaDB Corporation.
+Copyright (c) 2017, 2020, 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
@@ -236,6 +236,7 @@ static bool row_undo_mod_must_purge(undo_node_t* node, mtr_t* mtr)
 
 	btr_cur_t* btr_cur = btr_pcur_get_btr_cur(&node->pcur);
 	ut_ad(btr_cur->index->is_primary());
+	DEBUG_SYNC_C("rollback_purge_clust");
 
 	mtr->s_lock(&purge_sys.latch, __FILE__, __LINE__);
 
@@ -369,6 +370,7 @@ row_undo_mod_clust(
 	      == node->new_trx_id);
 
 	btr_pcur_commit_specify_mtr(pcur, &mtr);
+	DEBUG_SYNC_C("rollback_undo_pk");
 
 	if (err != DB_SUCCESS) {
 		goto func_exit;
diff --git a/storage/innobase/row/row0upd.cc b/storage/innobase/row/row0upd.cc
index 88a9f60206f..6ddd4046f09 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, 2019, MariaDB Corporation.
+Copyright (c) 2015, 2020, 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
@@ -223,7 +223,6 @@ row_upd_check_references_constraints(
 	dtuple_t*	entry;
 	trx_t*		trx;
 	const rec_t*	rec;
-	ulint		n_ext;
 	dberr_t		err;
 	ibool		got_s_lock	= FALSE;
 
@@ -240,7 +239,7 @@ row_upd_check_references_constraints(
 
 	heap = mem_heap_create(500);
 
-	entry = row_rec_to_index_entry(rec, index, offsets, &n_ext, heap);
+	entry = row_rec_to_index_entry(rec, index, offsets, heap);
 
 	mtr_commit(mtr);
 
@@ -341,7 +340,6 @@ wsrep_row_upd_check_foreign_constraints(
 	dtuple_t*	entry;
 	trx_t*		trx;
 	const rec_t*	rec;
-	ulint		n_ext;
 	dberr_t		err;
 	ibool		got_s_lock	= FALSE;
 	ibool		opened     	= FALSE;
@@ -359,8 +357,7 @@ wsrep_row_upd_check_foreign_constraints(
 
 	heap = mem_heap_create(500);
 
-	entry = row_rec_to_index_entry(rec, index, offsets,
-				       &n_ext, heap);
+	entry = row_rec_to_index_entry(rec, index, offsets, heap);
 
 	mtr_commit(mtr);
 
@@ -2803,9 +2800,9 @@ check_fk:
 
 	mtr_commit(mtr);
 
-	err = row_ins_clust_index_entry(
-		index, entry, thr,
-		node->upd_ext ? node->upd_ext->n_ext : 0);
+	err = row_ins_clust_index_entry(index, entry, thr, node->upd_ext
+					? node->upd_ext->n_ext
+					: dtuple_get_n_ext(entry));
 	node->state = UPD_NODE_INSERT_CLUSTERED;
 
 	mem_heap_free(heap);
diff --git a/storage/innobase/row/row0vers.cc b/storage/innobase/row/row0vers.cc
index 9fe183ecb29..5935b0a11ca 100644
--- a/storage/innobase/row/row0vers.cc
+++ b/storage/innobase/row/row0vers.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1997, 2017, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2019, MariaDB Corporation.
+Copyright (c) 2017, 2020, 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
@@ -153,15 +153,13 @@ row_vers_impl_x_locked_low(
 	const ulint rec_del = rec_get_deleted_flag(rec, comp);
 
 	if (dict_index_has_virtual(index)) {
-		ulint	n_ext;
 		ulint	est_size = DTUPLE_EST_ALLOC(index->n_fields);
 
 		/* Allocate the dtuple for virtual columns extracted from undo
 		log with its own heap, so to avoid it being freed as we
 		iterating in the version loop below. */
 		v_heap = mem_heap_create(est_size);
-		ientry = row_rec_to_index_entry(
-			rec, index, offsets, &n_ext, v_heap);
+		ientry = row_rec_to_index_entry(rec, index, offsets, v_heap);
 	}
 
 	/* We look up if some earlier version, which was modified by
diff --git a/storage/innobase/trx/trx0rec.cc b/storage/innobase/trx/trx0rec.cc
index 008e508f076..1ff18a2a7eb 100644
--- a/storage/innobase/trx/trx0rec.cc
+++ b/storage/innobase/trx/trx0rec.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
-Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2019, MariaDB Corporation.
+Copyright (c) 1996, 2019, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2017, 2020, 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
@@ -2435,8 +2435,6 @@ trx_undo_prev_version_build(
 	ut_a(ptr);
 
 	if (row_upd_changes_field_size_or_external(index, offsets, update)) {
-		ulint	n_ext;
-
 		/* We should confirm the existence of disowned external data,
 		if the previous version record is delete marked. If the trx_id
 		of the previous record is seen by purge view, we should treat
@@ -2477,17 +2475,16 @@ trx_undo_prev_version_build(
 		those fields that update updates to become externally stored
 		fields. Store the info: */
 
-		entry = row_rec_to_index_entry(
-			rec, index, offsets, &n_ext, heap);
-		if (index->is_primary()) {
-			n_ext += btr_push_update_extern_fields(
-				entry, entry->n_fields, update, heap);
-		}
+		entry = row_rec_to_index_entry(rec, index, offsets, heap);
 		/* The page containing the clustered index record
 		corresponding to entry is latched in mtr.  Thus the
 		following call is safe. */
 		row_upd_index_replace_new_col_vals(entry, index, update, heap);
 
+		/* Get number of externally stored columns in updated record */
+		const ulint n_ext = index->is_primary()
+			? dtuple_get_n_ext(entry) : 0;
+
 		buf = static_cast<byte*>(mem_heap_alloc(
 			heap, rec_get_converted_size(index, entry, n_ext)));