I originally posted this at http://dtrace.org/blogs/brendan/2011/07/06/breaking-down-mysqlpercona-query-latency-with-dtrace.
In May I spoke at PerconaLive 2011 in New York, giving a talk titled "Breaking Down MySQL/Percona Query Latency With DTrace". It was a great conference, and I'd recommend attending the next one if you get a chance. I also attended a number of the talks, and have also caught up on some via video and slides after the fact (video being much preferable).
My talk was very popular (over 80 attendees), however, it wasn't videoed. Due to interest in the topic, I've made an extended version of the talk that was recorded. At PerconaLive I got through the talk in 40 minutes, which included skipping through the last few demos. Without needing to race the clock this extended version goes for 90 minutes - which may be both a good and a bad thing - and I did do all the live demos.
The extended talk is in five parts, listed below. The slides are also here.
The demos are mostly in parts 4 and 5. You may like to start with them first:
For more information on DTrace and MySQL, you may like to see some of the other blog posts I've written on the topic.