Documentation Home
MySQL Internals Manual

MySQL Internals Manual  /  MySQL Client/Server Protocol  /  Semi-Synchronous Replication

14.11 Semi-Synchronous Replication

In MySQL 5.5 replication can optionally be made semi-synchronous instead of the traditionally asynchronous replication.

The clients COMMIT (or in auto-commit mode the current statement) waits until _one_ slave acknowledged that it received (not neccesarilly executed) the transaction or a timeout is reached. In case the timeout is reached, semi-sync replication is disabled.

For more information, see Semisynchronous Replication.

To see of the master supports semi-sync replication run:

SHOW VARIABLES LIKE 'rpl_semi_sync_master_enabled';

The slave requests semi-sync replication by sending:

SET @rpl_semi_sync_slave = 1;

which the master either responds with a OK_Packet if it supports semi-sync replication or with ERR_Packet if it doesn't.

User Comments
User comments in this section are, as the name implies, provided by MySQL users. The MySQL documentation team is not responsible for, nor do they endorse, any of the information provided here.
Sign Up Login You must be logged in to post a comment.