… NULL, city varchar(255) NOT NULL, PRIMARY KEY (id), KEY state (state) ) ENGINE=MyISAM; 3) Table with INT: CREATE TABLE cities_join ( id… NULL, city varchar(255) NOT NULL, PRIMARY KEY (id), KEY state_id (state_id) ) ENGINE=MyISAM; 4) Dictionary table for cities_join: CREATE… times faster than for MyISAM. This is great example of the case when Innodb is much faster than MyISAM for Read load. The…
Post: Using CHAR keys for joins, how much is the overhead ?
June 18, 2007 By 18 Comments
… varchar while sticking to utf8 character set which we had as default ? Joining on Char columns completes in 4.5 seconds on Innodb which is about 50% slower compared to Joining on Int, for MyISAM however… 6 times slower than joining on the integer. In fact this was expected as MyISAM uses key compression for varchar columns so random…
Post: To pack or not to pack - MyISAM Key compression
May 13, 2006 By 4 Comments
… not a bit longer rows is frequent reason of MyISAM performing better than Innodb. In this article I’ll get in a… biggest reason joins using string keys is so much slower compared to integer keys. Integer keys still best but for Innodb for…) unsigned NOT NULL , `c` varchar(20) NOT NULL default ”, KEY `c` (`c`), KEY `id` (`id`) ) ENGINE=MyISAM Index size: PACK_KEYS=DEFAULT…
Comment: Using CHAR keys for joins, how much is the overhead ?
June 19, 2007 By 18 Comments
… BIGINT slowed down join speed for MyISAM tables from 1.7 seconds to 3.8 seconds, which is slower than Innodb with chars… changing varchar(10) to varchar(255) in my “short” varchar join tests for Innodb table with utf8 encoding. This caused some degradation slowing down join speed…
Post: MySQL Indexing Best Practices: Webinar Questions Followup
August 16, 2012 By 4 Comments
… wants to replace longish (25-30) indexed varchars with an additional bigint column containing the …Innodb Table id2 is not needed pas part of second key as PRIMARY key is appended to it internally anyway. For MyISAM…. Q: Table1 has a primary key. Table2 joins to table1 using Table1′s primary key….
Post: High-Performance Click Analysis with MySQL
December 22, 2008 By 13 Comments
…joins. Watch Data Types Does your ad ID look like “8a4dabde-1c82-102c-ab13-0019b984eacd” and is it stored in a VARCHAR…of repairing huge MyISAM tables and taking downtime, I would not use MyISAM for anything but… this have to do with InnoDB? Data clustering. InnoDB‘s primary keys define the physical…
