Ahh, exhaustion of available db handles was going to be my guess ... cool.
Stopping AOLserver doesn't send a SIGTERM signal to the PG backend (or Oracle, for that matter, if you're using that RDMS). Should it? I don't think the answer is obviously "yes", just because you stop AOLserver doesn't mean that you don't want to record (say) the finalization of a credit card transaction that just cleared before you decided to restart AOLserver ... normally I think you'd want transactions that have started to run to completion.
As far as runaway queries on a handle, then ... if you have minimal stats enabled in PG you can query and find out exactly what query has run away with your backend and AFTER having checked it out manually, kill -TERM your backend or let it run to completion, whichever you prefer.
I think manual administration of the DB in this instance is better than having the AOLserver database driver "guess" for you, no?
