… FOR UPDATE. InnoDB provides REPEATABLE READ for read-only SELECT, but it behaves as if you use READ COMMITTED for all write queries, in… level (considering only the two most common isolation levels, REPEATABLE READ and READ COMMITTED). What is a gap lock? A gap lock is… based replication. If your application can deal with phantom reads and your binary log is in row format, changing the ISOLATION to READ COMMITTED…
Post: READ-COMMITED vs REPETABLE-READ in tpcc-like load
February 11, 2010 By 6 Comments
… had binary log enabled on RBR mode (as READ-COMMITED does not support STATEMENT based replication in 5.1), and everything was run…: READ-COMMITED is used rare than REPEATABLE-READ (default), that is less-tested READ-COMMITED does not work with statement-based replication in 5.1 with READ-COMMITED…
Post: How Does Semisynchronous MySQL Replication Work?
January 19, 2012 By 23 Comments
…replication, when you commit a transaction, the commit does not complete until all replicas have also committed successfully. In MySQL’s semi-synchronous replication, the commit…to read the relevant section of the MySQL manual. But read carefully, for example, the following sentences: When a commit …
Post: Percona XtraDB Cluster Feature 2: Multi-Master replication
January 19, 2012 By 16 Comments
…read. This gap between slave and master is the reason why this replication named “virtually synchronous replication“, not real “synchronous replication” The described behavior of COMMIT also has …
Post: INSERT INTO ... SELECT Performance with Innodb tables.
July 12, 2006 By 21 Comments
…MySQL Performance and concurrency ? The reason is – replication. In MySQL before 5.1 replication is statement based which means statements replied …retrieves latest committed row. So even if you’re operation in REPEATABLE-READ mode, this operation will be performed in READ-COMMITTED mode, potentially…
Post: MySQL Limitations Part 1: Single-Threaded Replication
October 20, 2010 By 16 Comments
… read-to-write ratio is. What are some workarounds? Here are a few I’ve seen: Use DRBD replication instead of MySQL replication. Problem: you end up with an idle standby server, which can’t be used for serving reads… thread. The worker thread would run up until the COMMIT, but not actually commit, and then report back to the coordinator thread…
Post: Finding your MySQL High-Availability solution – Replication
November 13, 2009 By 6 Comments
… MySQL replication which does not allow the master to be sure the slave has been updated before returning after a commit statement… are fine with some data loss rely on replication for HA and for read scaling. In addition to hardware failure, the level… more VIPs where read operations are sent. If replication on one of the MySQL servers lags behind too much, its read VIP will…
Post: Making MySQL Replication Parallel
January 30, 2007 By 1 Comment
… course the idea could be to wait on final commit stage and commit queries A and B in order defined by Master…/lock context. In this case replication could accumulate number of queries execute them in parallel and then commit all at once. None… file and setup multi-master replication so slave can read all of them in parallel you can get replication parallel enough for many…
Post: Can MySQL temporary tables be made safe for statement-based replication?
May 26, 2008 By 8 Comments
…1. row *************************** Master_Log_File: mysql-bin.000006 Read_Master_Log_Pos: 98 Relay_Log_File… from test.t; -> drop temporary table test.t; -> commit; -> end// master > delimiter; Now calling the stored… there’s clearly an opportunity to break replication here. It looks like this doesn’t…
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 17 Comments
… isolation level READ COMMITTED, then InnoDB normally does not lock the ‘gaps’, and it does not lock rows whose latest committed version does… this with care: you MUST use row-based binlogging and replication, and remember that the execution is not serializable. PZ: Cool… you have a battery-backed disk controller cache, then the commit returns in less than 100 microseconds. And if you do…
