In January I installed MySQL v4.09 (gamma) on my linux server to supprt a JSP app. I am considering upgrading to the latest (production) version of MySQL now as we are about to get a whole lot more users ... if it is ever to happen, now is the time.

The question is how painful/risky this is likely to be. I see the server RPM has changed name, and I suppose that means I can't use rpm -u (or are there any tricks for this?). If I install the new RPMs, will they overwrite my existing installation? Completely or only in part? How do I get the new setup to use the old database files? What else do I need to do?

The manuals describe major version upgrades (rather briefly) but don't give enough info to make me confident. I can take the server down for maintenance, but now would be a very bad time to have a major screw-up.