Quick MySQL performance check
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This document summarizes a MySQL Meetup that took place on September 8th, 2014. It includes the agenda for the meetup which involved registration, a speaker presentation on quick performance checks, and a networking session. The speaker Wayne Leutwyler presented on useful views for checking database performance and provided thresholds and recommendations for optimizing various MySQL variables if certain metrics were not within acceptable ranges. The document also briefly discussed some command line tools for system monitoring and ended by thanking the event sponsors.
Quick MySQL performance check
- 1. MySQL Meetup September 8th, 2014
- 2. Text Welcome! To the 1st of many MySQL Meetups!
- 3. Agenda: • Food and registration 5:30 - 6:30 • Speaker 6:30 - 7:00 • Questions 7:00 - 7:30 • Networking 7:30 - 8:00
- 4. Quick Performance Check Presented by: Wayne Leutwyler
- 5. When a quick look is needed. Weekday management fire drill. 2am OnCall page. Unhappy customer calls you to complain about response time. Or anytime you just want to see how a certain database server is performing.
- 6. The Views. Below are 6 views that I find very useful for day today performance check, or the 2am issue. v_InnoBPHitRate v_table_cache_used v_table_definition_cache_use v_thread_cache_hit v_thread_cache_used v_tmp_to_disk
- 7. v_InnoBPHitRate CREATE ALGORITHM = UNDEFINED DEFINER = `wayne`@`localhost` SQL SECURITY DEFINER VIEW `v_InnoBPHitRate` AS select round((100 - ((100 * `P2`.`VARIABLE_VALUE`) / `P1`.`VARIABLE_VALUE`)), 2) AS `InnoBP Hit Rate`, `P2`.`VARIABLE_VALUE` AS `InnoBP Read Requests (from disk)`, `P1`.`VARIABLE_VALUE` AS `InnoBP Reads (from BP)` from (`information_schema`.`GLOBAL_STATUS` `P1` join `information_schema`.`GLOBAL_STATUS` `P2`) where ((`P1`.`VARIABLE_NAME` = 'innodb_buffer_pool_read_requests') and (`P2`.`VARIABLE_NAME` = 'innodb_buffer_pool_reads')) I have always gone with 50% of total server ram for my InnoDB buffer pool. Recommendations range from 50% to 80%.
- 8. v_table_cache_used CREATE ALGORITHM = UNDEFINED DEFINER = `wayne`@`localhost` SQL SECURITY DEFINER VIEW `v_table_cache_used` AS select round(((`information_schema`.`global_status`.`VARIABLE_VALUE` / `information_schema`.`GLOBAL_VARIABLES`.`VARIABLE_VALUE`) * 100), 2) AS `Table Cache % Used` from (`information_schema`.`global_status` join `information_schema`.`GLOBAL_VARIABLES`) where ((`information_schema`.`global_status`.`VARIABLE_NAME` = 'opened_tables') and (`information_schema`.`GLOBAL_VARIABLES`.`VARIABLE_NAME` = 'table_open_cache')) Below 90% Adjust: table_open_cache
- 9. v_table_definition_cache_use CREATE ALGORITHM = UNDEFINED DEFINER = `wayne`@`localhost` SQL SECURITY DEFINER VIEW `v_table_definition_cache_used` AS select round(((`information_schema`.`global_status`.`VARIABLE_VALUE` / `information_schema`.`GLOBAL_VARIABLES`.`VARIABLE_VALUE`) * 100), 2) AS `Table Definition Cache % Used` from (`information_schema`.`global_status` join `information_schema`.`GLOBAL_VARIABLES`) where ((`information_schema`.`global_status`.`VARIABLE_NAME` = 'open_table_definitions') and (`information_schema`.`GLOBAL_VARIABLES`.`VARIABLE_NAME` = 'table_definition_cache')) Above 100% adjust: table_definition_cache
- 10. v_thread_cache_hit CREATE ALGORITHM = UNDEFINED DEFINER = `wayne`@`localhost` SQL SECURITY DEFINER VIEW `v_thread_cache_hit` AS select round((100 - ((`p1`.`VARIABLE_VALUE` / `p2`.`VARIABLE_VALUE`) * 100)), 2) AS `Thread Cache Hit Rate`, `p1`.`VARIABLE_VALUE` AS `Threads Created`, `p2`.`VARIABLE_VALUE` AS `Connections` from (`information_schema`.`global_status` `p1` join `information_schema`.`global_status` `p2`) where ((`p1`.`VARIABLE_NAME` = 'threads_created') and (`p2`.`VARIABLE_NAME` = 'connections')) Below 90% adjust: thread_cache_size
- 11. v_thread_cache_used CREATE ALGORITHM = UNDEFINED DEFINER = `wayne`@`localhost` SQL SECURITY DEFINER VIEW `v_thread_cache_used` AS select round(((`information_schema`.`global_status`.`VARIABLE_VALUE` / `information_schema`.`GLOBAL_VARIABLES`.`VARIABLE_VALUE`) * 100), 2) AS `Thread Cache % Used` from (`information_schema`.`global_status` join `information_schema`.`GLOBAL_VARIABLES`) where ((`information_schema`.`global_status`.`VARIABLE_NAME` = 'threads_cached') and (`information_schema`.`GLOBAL_VARIABLES`.`VARIABLE_NAME` = 'thread_cache_size')) Above 100% adjust: thread_cache_size
- 12. v_tmp_to_disk CREATE ALGORITHM = UNDEFINED DEFINER = `wayne`@`localhost` SQL SECURITY DEFINER VIEW `v_tmp_to_disk` AS select round(((`p1`.`VARIABLE_VALUE` / `p2`.`VARIABLE_VALUE`) * 100), 2) AS `Percent TMP to Disk` from (`information_schema`.`global_status` `p1` join `information_schema`.`global_status` `p2`) where ((`p1`.`VARIABLE_NAME` = 'CREATED_TMP_DISK_TABLES') and (`p2`.`VARIABLE_NAME` = 'CREATED_TMP_TABLES')) If percent is 25% or higher adjust: tmp_table_size max_heap_table_size
- 13. Command Line Tools When you cant find an issue with the DB, time to check the system. top iostat vmstat free
- 14. House Keeping Put your trash in the proper place. Don’t wonder around the building. Please put the chairs back the way they were. Please keep the noise down. We don’t want to disturb people still working.
- 15. Thank you! Percona for the food and drinks. CareWorks Tech for hosting our meeting.
- 16. Thank You questions? The views expressed in this presentation are mine alone.