Speed of InnoDB recovery is known and quite annoying problem. It was discussed many times, see: http://bugs.mysql.com/bug.php?id=29847 http://dammit.lt/2008/10/26/innodb-crash-recovery/ This is problem when your InnoDB crashes, it may takes long time to start. Also it affects restoring from backup (both LVM and xtrabackup / innobackup) In this is simple test, I do crash mysql during in-memory [...]
Goal driven performance optimization
December 22, 2008 By Leave a Comment
When your goal is to optimize application performance it is very important to understand what goal do you really have. If you do not have a good understanding of the goal your performance optimization effort may well still bring its results but you may waste a lot of time before you reach same results as [...]
How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
Our customers or prospective customers often ask us how we do a performance audit (it’s our most popular service). I thought I should write a blog post that will both answer their question, so I can just reply “read all about it at this URL” and share our methodology with readers a little bit. This [...]
Web Site Optimization: FrontEnd and BackEnd
June 26, 2008 By 12 Comments
I spent Monday and Tuesday this week on Velocity Conference It was quite interesting event worth attending and it was very good to see the problems in this are going beyond Apache, PHP, Memcache and MySQL. A lot of talks on this conference was focusing on what is called “FrontEnd”. The meaning of Frontend is [...]
How much overhead DRDB could cause ?
June 2, 2008 By 4 Comments
I was working with the customer today investigating MySQL over DRBD performance issues. His basic question was why there is so much overhead with DRBD in my case, while it is said there should be no more than 30% overhead when DRBD is used. The truth is – because how DRBD works it does not [...]
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; |
MySQL File System Fragmentation Benchmarks
March 21, 2008 By 28 Comments
Few days ago I wrote about testing writing to many files and seeing how this affects sequential read performance. I was very interested to see how it shows itself with real tables so I’ve got the script and ran tests for MyISAM and Innodb tables on ext3 filesystem. Here is what I found:
MySQL 4 to MySQL 5 Upgrade performance regressions
June 6, 2007 By 8 Comments
This week I already had two serious performance regression cases when upgrading from MySQL 4.0 and 4.1 to MySQL 5.0. By serious I mean several times performance difference not just 5-10% you often see for simple queries due to generally fatter code. The problem in both cases was MySQL 5.0 broken group commit bug. First [...]
Content delivery system design mistakes
February 11, 2007 By 9 Comments
This week I helped dealing with performance problems (part MySQL related and part related to LAMP in general) of system which does quite a bit of content delivery, serving file downloads and images – something a lot of web sites need to do these days. There were quite a bit of mistakes in design for [...]
Why do you need many apache children ?
February 5, 2007 By 15 Comments
I already wrote kind of about same topic a while ago and now interesting real life case makes me to write again Most Web applications we’re working with have single tier web architecture, meaning there is just single set of apache servers server requests and nothing else – no dedicated server for static content, no [...]
