MySQL Tunning

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Take this documentation as is, not as a definitive guide to tuning MySQL. There is a lot of information and knowledge which should be read before changing your MySQL configuration. The documentation has been created based on experience shared by OpenKM server administrator users.

Useful links which should be read:

User case 1


  • OpenKM Community Version

Server information

  • Virtualized Windows Server 2008
  • CPU: Intel Xeon X3470 @2.93GHz
  • RAM: 7GB
  • JVM settings for Tomcat: -Xms 3072 -Xmx 3072 -XX:PermSize=256m -XX:MaxPermSize=512m
  • Repository is 1GB

MySQL my.ini changes

  • innodb_buffer_pool_size=1792M
  • innodb_additional_mem_pool_size=16M
  • innodb_log_file_size=256M
  • innodb_log_buffer_size=8M

Using MySQL server InnoDB engine with the default configuration parameters in my.ini file can cause a serious performance bottleneck in applications with high database read write activity. MySQL should have enough RAM to be able to cache the repository and avoid the high Disk I/O activity.

The most important parameters are:

  • innodb_buffer_pool_size
  • innodb_additional_mem_pool_size
  • innodb_log_file_size
  • innodb_log_buffer_size

Nota advertencia.png According to database experts, innodb_buffer_pool_size should occupy the 70 percent of RAM of a dedicated database server!!!

Nota clasica.png Before changing these values, please read MySQL documentation carefully. Before making any changes you should make sure the MySQL server has been stopped correctly (check server log), otherwise the innodb will become corrupted and MySQL server will not restart

Considerations Repository is 1GB so 1792M is enough RAM for innodb_buffer_pool_size. The larger your repository, the more memory you need to allocate to innodb_buffer_pool_size. If you are using x86 MySQL server you cannot allocate RAM larger than 2GB.

Information collected from OpenKM forum post.

User case 2


  • OpenKM Community Version

Server information

  • CPU: Intel Xeon E5606 @2.13GHz
  • RAM: 4GB
  • System: Windows Server 2008, 64bit
  • JAVA_OPTS=-Xms256m -Xmx1024m -XX:PermSize=256m -XX:MaxPermSize=512m -Djava.awt.headless=true -Dfile.encoding=utf-8
  • Database size:2.5G
  • Repository size:40GB
  • 100,000 nodes(folders + documents)

MySQL my.ini changes

  • query_cache_size=0
  • table_open_cache=2000
  • tmp_table_size=16M
  • thread_cache_size=9
  • myisam_max_sort_file_size=100G
  • myisam_sort_buffer_size=32M
  • key_buffer_size=8M
  • read_buffer_size=64K
  • read_rnd_buffer_size=256K
  • sort_buffer_size=256K
  • innodb_additional_mem_pool_size=16M
  • innodb_log_buffer_size=8M
  • innodb_buffer_pool_size=1042M


Before optimization, the login time was about 45-55 seconds with a lot of hard-disk I/O usage. After the MySQL optimizations, login takes about 10 seconds.

Nota clasica.png Observation: With more RAM it will be possible to get a higher MySQL buffer and probably better performance

Information collected from OpenKM Forum post