One of the most common commands that a MySQL DBA performs is the SHOW FULL PROCESSLIST command. I can't tell you how many thousands of times I've run this. The problem is that there is too much information that I need to filter out before I can focus on the queries that matter. Fore xample, I don't want to see any idle connections nor do I want to see my own connection. The other problem is that if most queries run in under a second, I miss a lot of queries.
I have posted a very handy script named proclist.pl to MySQL Forge.This script can be used to periodically poll the server for queries, with millisecond precision. Moreover, the output can be imported into a MySQL database for further analysis.