… with a couple of mins gap on the same mysql prod instance . The first SQL query executed in 0.03 secs whereas… a single index. I would greatly appreciate your answer. First explain —————– explain SELECT LinksTbl2.id, LinksTbl2.title, LinksTbl2.url, PersonTbl2.firstname, PersonTbl2…
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 3 Comments
…MySQL in wild. I also wanted to share some troubleshooting techniques I use. Plot Memory Usage First I would like to see MySQL…created which temporary tables (both in memory and not): mysql> select * from information_schema.global_temporary_tables \G *************************** 1. row …
Post: Percona Live MySQL Conference & Expo Was A Great Event
April 17, 2012 By 2 Comments
…all of our sponsors, speakers, speaker selection committee, event staff, and especially the attendees for making… long time — some of them since the very first year. In a nutshell, if you weren’t … their new development milestone release for MySQL 5.6, released on Monday. MySQL 5.6 just keeps looking…
Post: Win Free MySQL Conference Tickets!
March 14, 2012 By 2 Comments
…us when we mention this contest Tweet “My favorite #MySQL conference session” with a link to your favorite “Like”…as an entry too.After a week, we’ll select the lucky winners at random from all of the…in Santa Clara, California on April 10th-12th Three first prizes are a free full conference pass to …
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 2 Comments
… Traditionally, MySQL always uses Nested Loop Join to join two or more tables. What this means is that, select rows from first table…. This join algorithm works best for highly selective queries, and obviously when the first operand used in the build step is such… 5479445 5527245 Select_scan 1 1 1 1 1 1 Sort_scan 1 1 1 1 1 1 The first obvious improvement…
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…
Comment: InnoDB's gap locks
April 13, 2012 By 14 Comments
…, KEY `i` (`i`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 mysql> select * from t; +——+——–+ | i | c | +——+——–+ | 1 | miguel | | 3 | andy | | 5…on the session 2 without closing the first one: session2> select * from t; +——+——-+ | i | c | +——+——-+ | 3 | andy | | 5 | aaron …
Post: InnoDB's gap locks
March 27, 2012 By 14 Comments
…SELECT. They only occur if you do UPDATE or DELETE or SELECT FOR UPDATE. InnoDB provides REPEATABLE READ for read-only SELECT…) After running the delete statement on the first session, not only the affected index record…1/en/innodb-locks-set.html. Conclusion MySQL uses REPEATABLE READ as the default …
Comment: ext4 vs xfs on SSD
April 24, 2012 By 23 Comments
Vadim, Selecting something as important as an Operating System or major component … matter look at the bug list or patch list for MySQL/InnoDB at any one point in time. The list will… of it, not for a pay check. So in the first count, you are reacting to a patch issue in a…
Post: Scaling problems still exist in MySQL 5.5 and Percona Server 5.5
May 20, 2011 By 11 Comments
…_range_first,handler::read_multi_range_next,QUICK_RANGE_SELECT::get _next,rr_quick,sub_select,do_select,JOIN::exec,mysql_select,handle_select,execute_sqlcom_select,mysql_execute…_next,QUICK_RANGE_SELECT::get_next,rr_quick,sub_select,do_select,JOIN::exec,mysql_select,handle_select,execu te_sqlcom_select,mysql_execute_command,mysql_parse,dispatch_command…
