Another db query I think slow things down.

My (inexpert) rule of thumb is that if you've gone to the trouble of getting a connection and have run one or more queries then running some more is unlikely to slow things down. The data you need may already be in the db's cache in which case it will be a lot quicker than getting Perl to do it.

Let the db take the strain. As Dolly Parton said, "It's what they're for!" although she was talking about something else. :-)