MDEV-18930: Failed CREATE OR REPLACE TEMPORARY not written into binary log makes data on master and slave diverge

Problem:
=======
Failed CREATE OR REPLACE TEMPORARY TABLE statement which dropped the table but
failed at a later stage of creation of temporary table is not written to
binarylog in row based replication. This causes the slave to diverge.

Analysis:
========
CREATE OR REPLACE statements work as shown below.

CREATE OR REPLACE TABLE table_name (a int);
is basically the same as:

DROP TABLE IF EXISTS table_name;
CREATE TABLE table_name (a int);

Hence every CREATE OR REPLACE TABLE command which dropped the table should be
written to binary log, even when following CREATE TABLE part fails. In order
to achieve this, during the execution of CREATE OR REPLACE command, when a
table is dropped 'thd->log_current_statement' flag is set. When table creation
results in an error within 'mysql_create_table' code, the error handling part
looks for this flag. If it is set the failed CREATE OR REPLACE statement is
written into the binary log inspite of error. This ensure that slave doesn't
diverge from the master. In case of row based replication the error handling
code returns very early, if the table is of type temporary. This is done based
on the assumption that temporary tables are not replicated in row based
replication.

It fails to handle the cases where a temporary table was created as part of
statement based replication at an earlier stage and the binary log format was
changed to row because of an unsafe statement. In this case when a CREATE OR
REPLACE statement is executed on this temporary table it will dropped but the
query will not be written to binary log. Hence slave diverges.

Fix:
===
In error handling code check the return status of create table operation. If
it is successful and replication mode is row based and table is of type
temporary then return. Other wise proceed further to the code which checks for
thd->log_current_statement flag and does appropriate logging.

3 files changed, 75 insertions, 1 deletions

diff --git a/mysql-test/suite/rpl/r/rpl_create_or_replace_fail.result b/mysql-test/suite/rpl/r/rpl_create_or_replace_fail.result
new file mode 100644
index 00000000000..57178f0efbe
--- /dev/null
+++ b/mysql-test/suite/rpl/r/rpl_create_or_replace_fail.result
@@ -0,0 +1,18 @@
+include/master-slave.inc
+[connection master]
+CREATE TEMPORARY TABLE t1 (a INT NOT NULL);
+LOAD DATA INFILE 'x' INTO TABLE x;
+ERROR 42S02: Table 'test.x' doesn't exist
+CREATE OR REPLACE TEMPORARY TABLE t1 (x INT) PARTITION BY HASH(x);
+ERROR HY000: Cannot create temporary table with partitions
+"************** DROP TEMPORARY TABLE Should be present in Binary log **************"
+include/show_binlog_events.inc
+Log_name	Pos	Event_type	Server_id	End_log_pos	Info
+master-bin.000001	#	Gtid	#	#	GTID #-#-#
+master-bin.000001	#	Query	#	#	use `test`; CREATE TEMPORARY TABLE t1 (a INT NOT NULL)
+master-bin.000001	#	Gtid	#	#	GTID #-#-#
+master-bin.000001	#	Query	#	#	use `test`; CREATE OR REPLACE TEMPORARY TABLE t1 (x INT) PARTITION BY HASH(x)
+CREATE TABLE t1 (b INT);
+INSERT INTO t1 VALUES (NULL);
+DROP TABLE t1;
+include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/t/rpl_create_or_replace_fail.test b/mysql-test/suite/rpl/t/rpl_create_or_replace_fail.test
new file mode 100644
index 00000000000..e75f34b0b56
--- /dev/null
+++ b/mysql-test/suite/rpl/t/rpl_create_or_replace_fail.test
@@ -0,0 +1,56 @@
+# ==== Purpose ====
+#
+# Test verifies that failed CREATE OR REPLACE TEMPORARY TABLE statement which
+# dropped the table but failed at a later stage of creation of temporary table
+# is written to binarylog in row based replication.
+#
+# ==== Implementation ====
+#
+# Steps:
+#    0 - Have mixed based replication mode.
+#    1 - Create a temporary table. It will be replicated as mixed replication
+#        mode is in use.
+#    2 - Execute an unsafe statement which will switch current statement
+#        binlog format to 'ROW'. i.e If binlog_format=MIXED, there are open
+#        temporary tables, and an unsafe statement is executed, then subsequent
+#        statements are logged in row format.
+#    3 - Execute a CREATE OR REPLACE TEMPORARY TABLE statement which tries to
+#        create partitions on temporary table. Since it is not supported it will
+#        fail.
+#    4 - Check the binary log output to ensure that the failed statement is
+#        written to the binary log.
+#    5 - Slave should be up and running and in sync with master.
+#
+# ==== References ====
+#
+# MDEV-18930: Failed CREATE OR REPLACE TEMPORARY not written into binary log
+# makes data on master and slave diverge
+#
+
+--source include/have_partition.inc
+--source include/have_binlog_format_mixed.inc
+--source include/master-slave.inc
+
+CREATE TEMPORARY TABLE t1 (a INT NOT NULL);
+
+# Execute an unsafe statement which switches replication mode internally from
+# "STATEMENT" to "ROW".
+--error ER_NO_SUCH_TABLE
+LOAD DATA INFILE 'x' INTO TABLE x;
+
+--error ER_PARTITION_NO_TEMPORARY
+CREATE OR REPLACE TEMPORARY TABLE t1 (x INT) PARTITION BY HASH(x);
+
+--echo "************** DROP TEMPORARY TABLE Should be present in Binary log **************"
+--source include/show_binlog_events.inc
+
+CREATE TABLE t1 (b INT);
+INSERT INTO t1 VALUES (NULL);
+--sync_slave_with_master
+
+# Cleanup
+--connection master
+DROP TABLE t1;
+
+--source include/rpl_end.inc
+
diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index 656834c7852..fe923d73200 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -5092,7 +5092,7 @@ bool mysql_create_table(THD *thd, TABLE_LIST *create_table,
 
 err:
   /* In RBR we don't need to log CREATE TEMPORARY TABLE */
-  if (thd->is_current_stmt_binlog_format_row() && create_info->tmp_table())
+  if (!result && thd->is_current_stmt_binlog_format_row() && create_info->tmp_table())
     DBUG_RETURN(result);
 
   if (create_info->tmp_table())