Well, this tells us that

An END code block is executed as late as possible, that is, after perl has finished running the program and just before the interpreter is being exited, even if it is exiting as a result of a die() function. (But not if it's morphing into another program via exec, or being blown out of the water by a signal--you have to trap that yourself (if you can).)

Emphasis mine. This suggests to me that updating a database would be Too Much for an END block.

But then, I'm just a Perl Pisher. One of the Perl Hackers should have something more definitive to say.