I am constantly referring to the amazing MySQL manual, especially the option and variable reference table. But just as frequently, I want to look up blog posts on variables, or look for content in the Percona documentation or forums. So I present to you what is now my newest Firefox toolbar bookmark: an option and [...]
Advanced index analysis with mk-index-usage
November 11, 2010 By 2 Comments
The new release of Maatkit has a useful feature in mk-index-usage to help you determine how indexes are used in more flexible ways. The default report just prints out ALTER statements for removing unused indexes, which is nice, but it’s often helpful to ask more sophisticated questions about index usage. I’ll use this blog’s queries [...]
InnoDB memory allocation, ulimit, and OpenSUSE
August 23, 2010 By 7 Comments
I recently encountered an interesting case. A customer reported that mysqld crashed on start on OpenSUSE 11.2 kernel 2.6.31.12-0.2-desktop x86_64 Â with 96 GB RAM when the innodb_buffer_pool_size was set to anything more than 62 GB. I decided to try it with 76 GB. The error message was an assert due to a failed malloc() [...]
How to pretty-print my.cnf with a one-liner
June 15, 2009 By 17 Comments
When I’m looking at a server, I often want to see the /etc/my.cnf file nicely formatted, and with comments stripped. This Perl one-liner will pretty-print the file:
1 2 3 4 5 6 7 8 9 10 11 12 13 | perl -ne 'm/^([^#][^\s=]+)\s*(=.*|)/ && printf("%-35s%s\n", $1, $2)' /etc/my.cnf [client] port = 3306 socket = /var/run/mysqld/mysqld.sock [mysqld_safe] socket = /var/run/mysqld/mysqld.sock nice = 0 [mysqld] user = mysql pid-file = /var/run/mysqld/mysqld.pid socket = /var/run/mysqld/mysqld.sock port = 3306 .... |
Another ingenious piece of Sun Marketing
March 20, 2009 By 20 Comments
So a while ago I wrote about fun post about MySQL Scalability to 256 way…. Besides discussion on the thread itself I had a lot of private comments in my mail from Sun/MySQL employees which tended to agree with me on this being the a large stretch.
Apache PHP MySQL and Runaway Scripts
May 20, 2008 By 20 Comments
Sometimes due to programming error or due to very complex query you can get your PHP script running too long, well after user stopped waiting for the page to render and went browsing other sites. Looking at Server-Status I’ve seen scripts executing for hours sometimes which is obviously the problem – they take Apache Slot, [...]
Updated msl (microslow) patch, installation walk-through!
April 20, 2008 By 17 Comments
For a couple of months there have been no updates to our msl patch, however recently I managed some time to change this. The functionality was extended a little bit and what’s even more important the patch is available for all the recent MySQL releases. To remind anyone who has not yet come across this [...]
PHP vs. BIGINT vs. float conversion caveat
January 10, 2008 By 27 Comments
Sometimes you need to work with big numbers in PHP (gulp). For example, sometimes 32-bit identifiers are not enough and you have to use BIGINT 64-bit ids; e.g. if you are encoding additional information like the server ID into high bits of the ID. I had already written about the mess that 64-bit integers are [...]
Debugging sleeping connections with MySQL
February 8, 2007 By 30 Comments
Have you ever seen connection in the SHOW PROCESSLIST output which is in “Sleep” state for a long time and you have no idea why this would happen ? I see if frequently with web applications and it is often indication of trouble. Not only it means you may run out of MySQL connections quicker [...]
