I have not caused a fist fight in a while, so it’s time to take off the gloves. I claim that somewhere around of 99% of advice about tuning MySQL’s key cache hit ratio is wrong, even when you hear it from experts. There are two major problems with the key buffer hit ratio, and [...]
How innodb_open_files affects performance
Recently I looked at table_cache sizing which showed larger table cache does not always provides the best performance. So I decided to look at yet another similar variable – innodb_open_files which defines how many files Innodb will keep open while working in innodb_file_per_table mode. Unlike MyISAM Innodb does not have to keep open file descriptor [...]
How much memory can MySQL use in the worst case?
I vaguely recall a couple of blog posts recently asking something like “what’s the formula to compute mysqld’s worst-case maximum memory usage?” Various formulas are in wide use, but none of them is fully correct. Here’s why: you can’t write an equation for it.
XtraDB/InnoDB CPU bound benchmarks on 24cores server
One of our customers gave me a chance to run some benchmarks on 24-core (intel cpu based) server, and I could not miss it and ran few CPU-bound tasks there. The goal of benchmarks was investigation of InnoDB-plugin and XtraDB scalability in CPU-bound load.
How Percona does a MySQL Performance Audit
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 [...]
New SpecJAppServer results at MySQL and Sun.
As you likely have seen Sun has posted the new SpecJAppServer Results More information from Tom Daly can be found here These results are quite interesting for me as I worked on some of the previous SpecJAppServer Benchmarks several years ago while being employed by MySQL. These are great results, plus they can be relevant [...]
Updated msl (microslow) patch, installation walk-through!
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 [...]
Heikki Tuuri answers to Innodb questions, Part II
I now got answers to the second portions of the questions you asked Heikki. If you have not seen the first part it can be found here. Same as during last time I will provide my comments for some of the answers under PZ and will use HT for original Heikkis answer. Q26: You also [...]
What to tune in MySQL Server after installation
My favorite question during Interview for people to work as MySQL DBAs or be involved with MySQL Performance in some way is to ask them what should be tuned in MySQL Server straight after installation, assuming it was installed with default settings. I’m surprised how many people fail to provide any reasonable answer to this [...]

