4.1.14 Replication and FLUSH

Some forms of the FLUSH statement are not logged because they could cause problems if replicated to a replica: FLUSH LOGS and FLUSH TABLES WITH READ LOCK. For a syntax example, see FLUSH Statement. The FLUSH TABLES, ANALYZE TABLE, OPTIMIZE TABLE, and REPAIR TABLE statements are written to the binary log and thus replicated to replicas. This is not normally a problem because these statements do not modify table data.

However, this behavior can cause difficulties under certain circumstances. If you replicate the privilege tables in the mysql database and update those tables directly without using GRANT, you must issue a FLUSH PRIVILEGES on the replicas to put the new privileges into effect. In addition, if you use FLUSH TABLES when renaming a MyISAM table that is part of a MERGE table, you must issue FLUSH TABLES manually on the replicas. These statements are written to the binary log unless you specify NO_WRITE_TO_BINLOG or its alias LOCAL.