… EXPLAIN phase yet making it unusable to check the optimizer performance. Solution for this problem was to use set optimizer_search… joining less number of tables. I was wondering if 0 is automatic selection why do we have value of 62 being default in MySQL 5… we can learn how automatic selection works – it picks value of min(number of tables, 7) essentially limiting search depth to no more than…
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 2 Comments
…table will be created based on the columns of table t1 that are two be used to join rows with table…first obvious improvement is shown by the high numbers of Innodb_buffer_pool_read_ahead when the …best possible performance gain. This is not entirely visible in the manual either for MariaDB or MySQL, …
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
… of ‘pk_column’ which is a part of the secondary key tuple, a point primary key lookup is made against base table, the number of these point primary key lookups will be depend on the number of rows that match the… were captured when performing the benchmark on IO bound workload, mentioned above. Counter Name MySQL 5.5 MySQL 5.6 MySQL 5.6 w…
Post: Index Condition Pushdown in MySQL 5.6 and MariaDB 5.5 and its performance impact
March 12, 2012 By 12 Comments
… in preparation for the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. We are taking a… optimizer enhancement Index Condition Pushdown (ICP). Its available in both MySQL 5.6 and MariaDB 5.5 Now let’s take…
Post: Announcing Percona XtraBackup 2.0.0 GA
April 4, 2012 By 11 Comments
…-threaded) compression utilities, which also had a number of other limitations (e.g. could not…table). Percona XtraBackup now supports streaming incremental backups. In previous versions streaming backups were performed…will be part of the topics at the upcoming Percona Live MySQL Conference and …
Comment: Should you move from MyISAM to Innodb ?
March 10, 2012 By 53 Comments
…in the MySQL community are snobbish about using MyISAM (not using it … too smart. However, InnoDB brings a lot of cons to the table which are missing in MyISAM and vice-versa…. MyISAM. If you have a huge number of concurrent writes and selects and query performance must be consistently fast in this …
Post: Using VIEW to reduce number of tables used
September 28, 2007 By 12 Comments
… VIEWs to reduce number of tables dramatically – merging say 1000 of users to the same table as VIEWs are… to be different for each of the views. You could think MySQL would look at the…specially INSTEAD OF triggers so you could write triggers to perform insert inserts to base tables instead of views….
Post: Performance gotcha of MySQL memory tables
February 1, 2008 By 5 Comments
One performance gotcha with MEMORY tables you might know about comes from the fact it is the only MySQL storage engine which defaults… 1.000.000 rows ALL of them having same value for c column. Now I’m performing random deletes by primary key… memory. MyISAM however had to perform number of random writes to the key file and data file. They of course were buffered by operation…
Post: Performance Schema tables stats
May 2, 2011 By 2 Comments
…able to get from performance schema tables. 1. table_io_waits_summary_by_table mysql> select * from table_io_waits_summary_by_table where OBJECT_NAME=’… 19916 SUM_NUMBER_OF_BYTES_READ: 361611264 SUM_NUMBER_OF_BYTES_WRITE: 326303744 or we can get top tables that required read IO mysql> select * from…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
… explanation in our book, High Performance MySQL 2nd Edition (it’s not…of tables, but at this point I should have identified a handful of tables that really matter. That’s why I save this part of…of the analysis we do. A lot of times, customers will tell us up front to limit the work to some number of…
