MySQL Proxy is one of the new products that MySQL released this year that has some real promise. In the MySQL Proxy, the Friendly Man in the Middle session Jan Kneschke went over the existing and planned features of the proxy.
MySQL Proxy has a c-based event driven core that has command line support, event handling and a Lua-based scripting layer. The proxy is loading into MySQL via the plugin interface. With the community edition, you are responsible for writing your own scripts. But with MySQL Enterprise, it will come with several pre-built scripts that add some enhanced functionality.
The most basic use of MySQL Proxy is to rewrite or alter your queries. If you have a costly query that is killing your db, but you’re not sure where it is coming from, you can write a Lua script to either reject the query or to alter it and make it more manageable. It stops the dba from having to wait for a developer to update code and/or deploy the fix.
Another trick you can do with MySQL Proxy is to create new SQL commands. While this is probably not going to be a great idea, you can see a few interesting examples at http://thenoyes.com/littlenoise/?p=63. It is a good way to expand on functionality at the lowest level. Or to lose/forget where you put it when you switch to another db.
This post was written by Michael Tougeron on April 21, 2008