… can find all unused indexes (since last restart of mysqld) by single query SELECT DISTINCT s.TABLE_SCHEMA, s.TABLE_NAME, s.INDEX_NAME FROM information_schema.statistics `s` LEFT JOIN information_schema.index_statistics…
Post: Dropping unused indexes
January 15, 2009 By 6 Comments
…unused indexes with single query. I was working on the system today and found hundreds of unused indexes on dozens of tables so just dropping indexes…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
…they are pretty much unusable. To be honest I…reads originated from query executions are executed by threads running queries. On…by adaptive hash index. You can also see number of hash index lookups and number of non-hash index… need to be flushed by checkpointing process and single page – independent …
Post: Tuning InnoDB Concurrency Tickets
May 24, 2010 By 4 Comments
…unused parameter innodb_concurrency_tickets that seems…can enter InnoDB concurrently is determined by the innodb_thread_concurrency variable. …ALTER TABLE test_table ADD INDEX (id); — 5 Tickets Used Query OK, 3 rows affected (…I have two distinct access patterns: single row primary-key lookups and …
Post: Economics of Performance Optimization
March 13, 2008 By 9 Comments
… well and add has higher risks – adding index you rarely would add bugs to your … replacement may not be available and keeping unused spare box can be expensive. Because fewer …single user CPU bound query takes 30 seconds you unlikely will be able to solve the problem by CPU upgrade. For single…
