On Oct. 25th I will be presenting my conference session “Keep your MySQL backend online no matter what” at the Percona Live London Conference. Considering their is a variety of highly knowledgeable MySQL experts speaking at this event I wanted to give my talk a special plug so you won’t miss THIS knowledgeable MySQL expert [...]
About Istvan Podor
Istvan's expertise is high-traffic websites driven by MySQL. Prior to joining Percona in 2009, Istvan worked for several Alexa Top 500 websites on high availability solutions and high load performance tuning.
Upcoming webinar on Data Recovery for MySQL
April 6, 2011 By 5 Comments
I’ll be giving a 40-50 minute long webinar on 26th of April on data recovery for MySQL. Almost every long serving DBA has been faced with the task of recovering data from a database, whether it be via user error such as a erroneously dropped table or from Hardware or Software failure. In this Webinar [...]
When the subselect runs faster
March 18, 2010 By 9 Comments
A few weeks ago, we had a query optimization request from one of our customer. The query was very simple like:
1 | SELECT * FROM `table` WHERE (col1='A'||col1='B') ORDER BY id DESC LIMIT 20 OFFSET 0 |
This column in the table is looks like this:
1 | `col1` enum('A','B','C','CD','DE','F','G','HI') default NULL |
The table have 549252 rows and of course, there is an index on the col1. MySQL estimated the cardinality of that index as [...]
