June 19, 2013

Post: MySQL 4 to MySQL 5 Upgrade performance regressions

… was MySQL 5.0 broken group commit bug. First I should note I am extremely unhappy how MySQL handled this problem. While working for MySQL we… transactions so group commit would trigger in MySQL 4.0 and large number of transactions in total so serializing them would make MySQL unable…

Post: Group commit and real fsync

… at two issues here which interleave such funny way Group commit is broken in MySQL 5.0 if binary loging is enabled (as it… was implemented in MySQL 5.0 which did not work with former group commit code. The new code for group commit however was never implemented…. if binary log is disabled, so is XA and old group commit code works just fine. Second one is interesting. Actually we…

Post: When would you use SAN with MySQL ?

… managing a lot of relatively small MySQL installations or managed hosting provider. For large MySQL web MySQL installations using Sharding or replication IO… on commit too. MySQL also has broken group commit (which we have partial fix for) meaning concurrent transaction commits will need to be serialized. Second, MySQL is…

Comment: When would you use SAN with MySQL ?

Peter, “MySQL also has broken group commit (which we have partial fix for) meaning concurrent transaction commits will need to be serialized.” I would also… if several transactions could be grouped into one commit. At least this is how I read the original group commit code from 4.x…

Post: XtraDB storage engine release 1.0.2-3 (Spring edition) codename Sapporo

… storage engine. Here is a list of enhancements: Move to MySQL 5.1.31 Scalability fix — ability to use several…. See benchmark results. Fix broken group commit in InnoDB As you know, the group commit of InnoDB doesn’t work after MySQL 5.0 with binlog. We pretend to fix this and added “innodb_enable_unsafe_group_commit

Post: Watch out for Marketing benchmarks

MySQL 5.0 was stable but were not fixed, others, such as broken group commit could have been handled better. Same applies to comparing MySQL to other vendors. If you ask me if MySQL is faster…

Post: Announcing Percona Server 5.5.27-29.0

… available here and from the Percona Software Repositories). Based on MySQL 5.5.27, including all the bug fixes in it… (George Ormond Lorch III). Option expire_logs_days was broken by group_commit patch introduced in Percona Server 5.5.18-23.0… a non-default maximum number of indexes per table. Upstream MySQL bugs: #54127, #61178, #61179 and #61180. Bug fixed #1042517 (Sergei…

Comment: Group commit and real fsync

[...] originally performed InnoDB scalability tests for MySQL 5.0 to show broken group commit [...]

Comment: Group commit and XA

[...] problem in both cases was MySQL 5.0 broken group commit [...]

Comment: Group commit and real fsync

[...] Of course I would not say it is normal and nothing can be done in all cases. There are performance bugs, some of them as Innodb Scalability were known long before MySQL 5.0 was stable but were not fixed, others, such as broken group commit could have been handled better. [...]