Is it important to leave mysql running in the background ? Is there a gui to control processes on Ubuntu 12.04?

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http://askubuntu.com – Im using BootUp Manager (bum) to control auto-start processes on Ubuntu 12.04. I have stopped Apache2 from starting automatically using bum. The problem is, today I have found that sql server is always running in the back. I can not alter auto-start settings for MYSQL from bum. Why I can not see any entry for MySQL in bum, moreover does sql needed by the Ubuntu OS itself for its own processes ? If not needed by the OS itself ,then is it safe to disable MySQL and restart it whenever I need it ? How should I do that ? Is there any gui application for doing so ? Upto now Im using this command f (HowTos)