Percona is glad to announce the release of Percona Playback 0.5 on November 26th, 2012. Downloads are available from our download site and Percona Software Repositories. Percona Playback is a tool for replaying the load of one database server to another. Currently it can read queries from MySQL query-log and tcpdump files and run them [...]
Data mart or data warehouse?
July 15, 2010 By 13 Comments
This is part two in my six part series on business intelligence, with a focus on OLAP analysis. Part 1 – Intro to OLAP Identifying the differences between a data warehouse and a data mart. (this post) Introduction to MDX and the kind of SQL which a ROLAP tool must generate to answer those queries. [...]
ANALYZE: MyISAM vs Innodb
September 3, 2008 By 9 Comments
Following up on my Previous Post I decided to do little test to see how accurate stats we can get for for Index Stats created by ANALYZE TABLE for MyISAM and Innodb. But before we go into that I wanted to highlight about using ANALYZE TABLE in production as some people seems to be thinking [...]
The new cool MySQL patch has landed! Check your queries performance!
October 31, 2007 By 16 Comments
Microslow patch is used by many DBAs and developers to accurately time their queries and to catch those which run less than a second as they can also be a performance killer for a busy application. Recently I have started the development of an updated version of the patch. The basic idea is the same [...]
When EXPLAIN can be misleading
November 12, 2006 By 1 Comment
One think I can see with people using EXPLAIN is trusting it too much, ie assuming if number of rows is reported by EXPLAIN is large query must be inefficient. It may not be the case. The question is not only about stats which may be wrong and which is why you may want to [...]
Slow Query Log analyzes tools
September 6, 2006 By 84 Comments
MySQL has simple but quite handy feature – slow query log, which allows you to log all queries which took over define number of seconds to execute. There is also an option to enable logging queries which do not use indexes even if they take less time (–log-queries-not-using-indexes) Slow query log is great to spot [...]
