MySQL Performance Blog

Recently I looked at table_cache sizing which showed larger table cache does not always provides the best performance. So I decided to look at yet another similar variable – innodb_open_files which defines how many files Innodb will keep open while working in innodb_file_per_table mode.

Unlike MyISAM Innodb does not have to keep open file descriptor when table is open – open table is purely logical state and appropriate .ibd file may be open or closed. Furthermore besides MySQL table_cache Innodb maintains its own (called data dictionary) which keeps all tables ever accessed since table start – there is no variable to control its size and it can take significant amount of memory in some edge cases. Percona patches though provide innodb_dict_size_limit to restrict growth of data dictionary.
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Dear Community,

We are pleased to present the 20th build of MySQL server with Percona patches.

Comparing to the previous release it has following new features:

• The build is based on MySQL-5.0.87
• innodb_rw_lock.patch is ported from InnoDB Plugin 1.0.3
• To be compatible with RedHat RPM repository, the naming scheme has changed to

  <rpm name>-<mysql version>-<percona build version>.<buildnumber>.<redhat version>.<architecture>.rpm

  Example:

  MySQL-server-percona-5.0.87-b20.29.rhel5.x86_64.rpm

See release notes for earlier changes.

Since the build 20 MySQL server with Percona patches is available in Percona RPM repository via YUM. To make it working add a file Percona.repo in /etc/yum.repos.d with following content

As usual you can download binaries and sources with the patches here
http://www.percona.com/mysql/5.0.87-b20/

There is Debian packages repository is also available. See release page for configuration and usage guideance.

The Percona patches live on Launchpad : https://launchpad.net/percona-patches and you can report bug to Launchpad bug system:

https://launchpad.net/percona-patches/+filebug. The documentation is available on our Wiki

For general questions use our Pecona-discussions group, and for development question Percona-dev group.

For support, commercial and sponsorship inquiries contact Percona.

innodb_rw_lock.patch