Upgrading from MySQL 5.0 to MySQL 5.1 or Percona Server 5.1 you may run into issues with mysql_upgrade – it will identify some tables to be upgraded and will attempt to run REPAIR TABLE for them. This will fail with “The storage engine for the table doesn’t support repair” error message. This seems to confuse [...]
Rebuilding MySQL with same options
April 8, 2010 By 4 Comments
Every so often I am working on the system with custom compiled MySQL. How to upgrade to the new MySQL Options while preserving as much of original compilation options as possible if original build scripts are not available ? MySQL distribution has a great script called mysqlbug which was supposed to be used for bug [...]
Paul McCullagh answers your questions about PBXT
November 20, 2009 By 2 Comments
Following on from our earlier announcement, Paul McCullagh has responded with the answers to your questions – as well as a few I gathered from other Percona folks, and attendees of OpenSQL Camp. Thank you Paul! What’s the “ideal” use case for the PBXT engine, and how does it compare in performance?  When would I [...]
InnoDB: look after fragmentation
November 5, 2009 By 12 Comments
One problem made me puzzled for couple hours, but it was really interesting to figure out what’s going on. So let me introduce problem at first. The table is
1 2 3 4 5 6 7 8 | CREATE TABLE `c` ( `tracker_id` int(10) unsigned NOT NULL, `username` char(20) character set latin1 collate latin1_bin NOT NULL, `time_id` date NOT NULL, `block_id` int(10) unsigned default NULL, PRIMARY KEY (`tracker_id`,`username`,`time_id`), KEY `block_id` (`block_id`) ) ENGINE=InnoDB |
Table has 11864696 rows and takes Data_length: 698,351,616 bytes on disk The problem is that after restoring table from mysqldump, the query that scans data [...]
What to do with MySQL Full Text Search while migrating to Innodb ?
September 10, 2009 By 12 Comments
It is rather typical for systems to start as MyISAM but as system growths to move to Innodb. The reason of the move could be just desire for better data consistency guaranty or being bitten repairing multiple GB MyISAM table few times, though Table Locks is probably the most important issue – with modern multi [...]
Recovering CREATE TABLE statement from .frm file
December 17, 2008 By 5 Comments
So lets say you have .frm file for the table and you need to recover CREATE TABLE statement for this table. In particular when we do Innodb Recovery we often get .frm files and some mess in the Innodb tablespace from which we have to get data from. Of course we could relay on old [...]
Poor man’s query logging
November 7, 2008 By 5 Comments
Occasionally there is a need to see what queries reach MySQL. The database provides several ways to share that information with you. One is called general log activated with
1 | --log |
(or
1 | --general-log |
in MySQL 5.1+) start-up parameter. The log writes any query being executed by MySQL to a file with limited amount of additional information. [...]
Picking datatype for STATUS fields
August 9, 2008 By 24 Comments
Quite commonly in the applications you would need to use some kind of “status” field – status of order – “new”, “confirmed”, “in production”, “shipped” status of job, message etc. People use variety of ways to handle them often without giving enough thought to the choice which can cause problems later. Perhaps worst, though quite [...]
The #1 mistake hosting providers make for MySQL servers
July 25, 2008 By 30 Comments
This article is not meant to malign hosting providers, but I want to point out something you should be aware of if you’re getting someone else to build and host your servers for you. Most hosting providers — even the big names — continue to install 32-bit GNU/Linux operating systems on 64-bit hardware. This is [...]
Recovering Innodb table Corruption
July 4, 2008 By 21 Comments
Assume you’re running MySQL with Innodb tables and you’ve got crappy hardware, driver bug, kernel bug, unlucky power failure or some rare MySQL bug and some pages in Innodb tablespace got corrupted. In such cases Innodb will typically print something like this: InnoDB: Database page corruption on disk or a failed InnoDB: file read of [...]
