I got an email from a former colleague today. The mail contained a link to a tool, which he has been developing for the past months. It is a standalone software that will constantly collect statistical data from your MySQL database server. The data that is polled contains information about queries, users, tables etc. and will be aggregated, to give you the opportunity to find problem areas fast.
Jet Profiler is not free, but there is a free version that you can download. So I got myself a copy of the Linux version to try it out. Installation is simply extracting the archive and starting a bash script file. The tool is very simple to get started with, you don't even need the documentation. You define a connection to your MySQL database and how often you want to poll for data. Finally you click the record button and Jet Profiler will start to monitor your database server.
When running in record mode, you of course have to generate some load on your database server. Running some real life applications would be best, so I started my Jboss AS and ran a couple of unit tests. It was nice to see which queries where run most and which schemas were accessed more often than others. My test setup was a bit made up of course. No practical use for the results I got from Jet Profiler. In real applications however, this tool might be gold. If you are running an application that is using MySQL as database, you can easily find bottlenecks and performance killers. Try it out for yourself.