Dror,
> Ouch. I just double checked and you're right. Is this considered a bug,
> or just an implementation issue?
It's an implementation issue, which may be fixed by 7.5 but not sooner.
Basically, the free ability of PostgreSQL users to define their own
aggregates limits our ability to define query planner optimization for
aggregates. Only recently has anyone suggested a feasable way around this.
> While I've seen this hint a few times in the lists, it seems like it's
> one of those magic incantations that those in the know, know about, and
> that people new to postgres are going to be surprised by the need to use
> this idiom.
It IS in the FAQ.
--
Josh Berkus
Aglio Database Solutions
San Francisco