cache statement handles, uneeded finish()

[mortonda@…]

We spend a lot of time preparing sql statements that could be cached very easily by DBI's prepare_cached() call. This might be a simple way to speed up the database layer some... at the very least, reduce some waste.

Also mentioned in that documentation is that finish() is only needed when you know you are leaving the statement with unfetched rows. We could eliminate a lot of those calls.