After upgrading to 4.x I noticed the introduction of relay logs. I never saw them in 3.x so I presume it's a new "feature"?

Essentially the slave server now saves every command from the masters' update log as it receives them. It writes them to the local filesystem, apparently after - not before - executing them.

Why? I have no idea. I can't see any real use for this.

But whats far more annoying is that I cannot find _any_ way to rotate / rollover / DELETE! this stuff short of stopping and starting MySQL.

Which I'm sure none of you like me doing when you're in the middle of a post ;-) But if fills up around 300mb every couple of days so something needs to be done.

Anyone have any suggestions?