http://s.petrunia.net/blog Random observations made while working on MySQL / MariaDB query optimizer Tue, 16 Feb 2010 20:02:55 +0000 http://backend.userland.com/rss092 en At FOSDEM 2010, MariaDB was represented by Kristian Nielsen and me. Together with Vlad Kolesnikov we've manned the joint MariaDB & PBXT stand. I've had the main track talk titled "MariaDB: extra features that make it a better branch of MySQL" (slides), and Kristian had a more general talk titled ... http://s.petrunia.net/blog/?p=60 The main focus of MariaDB staff has been the MariaDB 5.1.38 release in recent weeks, but this doesn't mean that we've abandoned everything else for it. There are several non-release projects going on, one of which is adding binlog filtering and markup capabilities. In order to see how the new features ... http://s.petrunia.net/blog/?p=59 MariaDB 5.1 beta is almost out, so it's time to cover some of its features. The biggest optimizer feature is MWL#17 Table Elimination. The basic idea behind table elimination is that sometimes it is possible to resolve the query without even accessing some of the tables that the query refers ... http://s.petrunia.net/blog/?p=58 And it has failed the testuite on every single build slave. I've filed BUG#45605, BUG#45630 (together with a patch), BUG#45631, BUG#45632. There is also rpl.rpl_innodb_bug28430 test failure which I didn't report as I don't yet have enough details about the build slave. At the moment our setup works as follows: there ... http://s.petrunia.net/blog/?p=57 This is what's happening at the moment. 5.1 tree doesn't pass the tests, both Sun and Monty Program fix that, and the fixes are different. Here is a Valgrind warning which was fixed twice: my fix my fix (correct link) made the involved mysys function to do what its name ... http://s.petrunia.net/blog/?p=56 This isn't news anymore - it has been over a month - but it would be odd not to mention this all, so here it goes: at the start of May I've left Sun Microsystems and joined Monty's company. The setup at Monty Program AB is quite similar - we have ... http://s.petrunia.net/blog/?p=55 I was taking notes during "Open Q&A: Feature Request Bonanza" session at the Percona Performance conf. The session started at 9 pm at the last day of the conference, so the room wasn't as full as it was for other sessions, but still there was an interesting discussion. I've missed ... http://s.petrunia.net/blog/?p=54 In short, the news are: @@optimizer_switch support was backported into MySQL 5.1 The switch syntax was changed from 'no_optimization_name' to 'optimization_name=on|off|default'. Added switches for index_merge, index_merge_intersection, index_merge_union, and index_merge_sort_union optimizations. The changes will be available in next releases, that is, MySQL 5.1.34 and 6.0.11. Now with more details: New switch names Until now, the syntax mimicked an ... http://s.petrunia.net/blog/?p=52 Sun Tech Days St. Petersburg was on Wednesday-Thursday the last week and we've had a MySQL booth there. Unlike the last year, we're full part of Sun now so managed to get a decent-sized booth, arrange for leaflets, and Kostja gave an overall MySQL talk. Questions at the booth (in no ... http://s.petrunia.net/blog/?p=51 Three days ago I've finally managed to push the code for WL#3985 "Subquery optimization: smart choice between semi-join and materialization" into MySQL 6.0. I missed the clone-off date so it won't be in the upcoming MySQL 6.0.9 release, the only way to get it before the next 6.0.10 release is ... http://s.petrunia.net/blog/?p=50