MDEV-18930: Failed CREATE OR REPLACE TEMPORARY not written into binary log...
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.
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