There are two ways InnoDB can organize tablespaces. First is when all data, indexes and system buffers are stored in a single tablespace. This is typicaly one or several ibdata files. A well known innodb_file_per_table option brings the second one. Tables and system areas are split into different files. Usually system tablespace is located in [...]
Flexviews – part 3 – improving query performance using materialized views
April 4, 2011 By 20 Comments
Combating “data drift” In my first post in this series, I described materialized views (MVs). An MV is essentially a cached result set at one point in time. The contents of the MV will become incorrect (out of sync) when the underlying data changes. This loss of synchronization is sometimes called drift. This is conceptually [...]
MySQL Partitioning – can save you or kill you
December 11, 2010 By 44 Comments
I wanted for a while to write about using MySQL Partitioning for Performance Optimization and I just got a relevant customer case to illustrate it. First you need to understand how partitions work internally. Partitions are on the low level are separate table. This means when you’re doing lookup by partitioned key you will look [...]
Getting History of Table Sizes in MySQL
December 8, 2010 By 13 Comments
One data point which is very helpful but surprisingly few people have is the history of the table sizes. Projection of data growth is very important component for capacity planning and simply watching the growth of space used on partition is not very helpful. Now as MySQL 5.0+ has information schema collecting and keeping this [...]
A workaround for the performance problems of TEMPTABLE views
May 19, 2010 By 7 Comments
MySQL supports two different algorithms for views: the MERGE algorithm and the TEMPTABLE algorithm. These two algorithms differ greatly. A view which uses the MERGE algorithm can merge filter conditions into the view query itself. This has significant performance advantages over TEMPTABLE views. A view which uses the TEMPTABLE algorithm will have to compute the [...]
Statistics of InnoDB tables and indexes available in xtrabackup
September 14, 2009 By 6 Comments
If you ever wondered how big is that or another index in InnoDB … you had to calculate it yourself by multiplying size of row (which I should add is harder in the case of a VARCHAR – since you need to estimate average length) on count of records. And it still would be quite [...]
Talking MySQL to Sphinx
April 19, 2009 By 4 Comments
In the recently released Sphinx version 0.9.9-rc2 there is a support for MySQL wire protocol and SphinxQL – SQL-like language to query Sphinx indexes. This support is currently in its early preview stage but it is still fun to play with. A thing to mention – unlike MySQL Storage Engines, some of which as InfoBright [...]
Beware of MySQL Data Truncation
February 7, 2009 By 4 Comments
Here is nice gotcha which I’ve seen many times and which can cause just a minefield for many reasons. Lets say you had a system storing articles and you use article_id as unsigned int. As the time goes and you see you may get over 4 billions of articles you change the type for article_id [...]
How to load large files safely into InnoDB with LOAD DATA INFILE
July 3, 2008 By 29 Comments
Recently I had a customer ask me about loading two huge files into InnoDB with LOAD DATA INFILE. The goal was to load this data on many servers without putting it into the binary log. While this is generally a fast way to load data (especially if you disable unique key checks and foreign key [...]
Testing InnoDB “Barracuda” format with compression
April 23, 2008 By 3 Comments
New features of InnoDB – compression format and fast index creation sound so promising so I spent some time to research time and sizes on data we have on our production. The schema of one of shards is
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 | CREATE TABLE `article87` ( `id` bigint(20) unsigned NOT NULL, `ext_key` varchar(32) NOT NULL, `site_id` int(10) unsigned NOT NULL, `forum_id` int(10) unsigned NOT NULL, `thread_id` varchar(255) CHARACTER SET latin1 NOT NULL, `published` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00', `crawled` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00', `subject` varchar(255) NOT NULL, `title` varchar(255) NOT NULL, `url` varchar(255) NOT NULL, `num_links` smallint(6) NOT NULL, `links_in` int(10) unsigned NOT NULL, `cache_author` varchar(255) NOT NULL, `cache_site` varchar(255) DEFAULT NULL, `anchor` varchar(255) NOT NULL, `isthread` tinyint(3) unsigned NOT NULL, `author_id` int(10) unsigned NOT NULL, `inserted` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, `fromfile` varchar(255) NOT NULL, `language_id` tinyint(3) unsigned NOT NULL, `encoding` varchar(255) NOT NULL, `warning` mediumtext NOT NULL, `is_thread_start` tinyint(3) unsigned NOT NULL, `source` mediumint(8) unsigned NOT NULL, `hash` char(32) NOT NULL, `mod_is` tinyint(3) unsigned NOT NULL DEFAULT '0', `is_adult` tinyint(3) unsigned NOT NULL DEFAULT '0', `bodyuc` mediumtext NOT NULL, PRIMARY KEY (`id`), KEY `ext_key` (`ext_key`), KEY `forum_id` (`forum_id`,`thread_id`,`published`), KEY `site_id` (`site_id`,`published`), KEY `hash` (`hash`), KEY `forum_id_2` (`forum_id`,`is_thread_start`,`published`), KEY `published` (`published`), KEY `inserted` (`inserted`), KEY `forum_id_3` (`forum_id`,`thread_id`,`is_thread_start`), KEY `site_id_2` (`site_id`,`author_id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; |
