… fsyncs. It is simple code which does not even have “group commit” allowing to flush several events with single write to disk… logging it however can do group commit, meaning it can commit several transactions which are waiting to be commited at the same time with… management systems) – once transaction is commited the data is recorded in Innodb log files before COMMIT returns. The data pages are however…
Comment: Testing the Group Commit Fix
July 13, 2011 By 13 Comments
….mysqlperformanceblog.com/2009/02/02/pretending-to-fix-broken-group-commit/ Before the latest group commit fix turning on bin-log resulted in over… much performance drop does bin-log cause now with the group commit fix. 2) In your results did you use innodb_support…
Comment: Testing FusionIO: strict_sync is too strict...
June 18, 2009 By 8 Comments
… you can think of the sync writes as participating in group commits that are either triggered by reaching a certain combined size… the last write that reaches the combined “group commit” size will overflow into the next “group commit“. Hope this helps and again – strict_sync…
Post: XtraDB storage engine release 1.0.2-3 (Spring edition) codename Sapporo
March 2, 2009 By 10 Comments
…-write lock. See benchmark results. Fix broken group commit in InnoDB As you know, the group commit of InnoDB doesn’t work after MySQL…. We pretend to fix this and added “innodb_enable_unsafe_group_commit=[0|1]” parameter. Note if you set this parameter to…
Post: Jeremy Cole on MySQL Replication
May 27, 2006 By 12 Comments
…_bin. Innodb tables also have to flush logs on transaction commit unless you disable it so you should not be getting… Binary log with MySQL 5.0 you loose group commit which can dramatically increase commit rate for multiple user load. See this post… single stream so group commit can’t work. Furthermore even if you run with innodb_flush_logs_at_trx_commit=2 you still…
Comment: Benchmarking Galera replication overhead
October 14, 2011 By 12 Comments
Andy, I do have innodb_flush_log_at_trx_commit=2 and sync_binlog=0. Yes I know it is … for other nodes joining cluster. Please note that effect broken group commit you will see rather on slow disks or RAID with… Fusion-io cards as in this case, the problem with group commit is not significant.
Comment: Benchmarking Galera replication overhead
October 14, 2011 By 12 Comments
…_xa? 3) What values of innodb_flush_log_at_trx_commit did you use? 4) You mentioned “main overhead may coming… every single transaction? Or does it use some sort of “group commit” for writing to write sets to disk? 5) I’m… slower than regular replication. When binlog & sync_bonlog are enabled, group commit is broken and performance can drop by over 90%. Since…
Comment: Testing the Group Commit Fix
July 13, 2011 By 13 Comments
… always assumed there would still be a small gain from group commit also in that case. I suppose I’m also interested… no-binlog, and possibly also innodb_flush_log_at_trx_commit=0. This would give a “best case” baseline to see… measurement for production use, rather it sets a goal for group commit developers to try to achieve. (Of course, it’s only…
Comment: Product to try: MySQL/MariaDB-Galera 0.8
June 13, 2011 By 34 Comments
… is single node with both innodb_flush_log_at_trx_commit=1 and sync_binlog=1, and two Galera nodes with… you use an InnoDB version with group commit bug fixed or not. If you have the group commit bug, then it is easy to…
Comment: Evaluating IO subsystem performance for MySQL Needs
March 5, 2008 By 23 Comments
Sudheer, Enabling binary log breaks group commit which is critical with group commit. you can try setting innodb_flush_log_at_trx_commit=2
