Google Selects MySQL Goodies For Open Source

Some of Google applications use the MySQL database, and internal performance enhancements made by Google engineers have been publicly released.

He listed the following changes available as patches to MySQL version 4. They anticipate version 5 support as coming soon:

• SemiSyncReplication - block commit on a master until at least one slave acknowledges receipt of all replication events.


• MirroredBinlogs - maintain a copy of the master's binlog on a slave


• TransactionalReplication - make InnoDB and slave replication state consistent during crash recovery


• UserTableMonitoring - monitor and report database activity per account and table


• InnodbAsyncIo - support multiple background IO threads for InnoDB


• FastMasterPromotion - promote a slave to a master without restart

  Though Callaghan refers to a GPL license, the MySQL tools Google has released are listed under the license is not compatible with the GPL due to the inclusion of certain patent termination cases that the GPL does not have.