Re: [PERFORM] Slow count(*) again...

Tom Lane wrote:
> Andrew Dunstan <andrew(at)dunslane(dot)net> writes:
> > On 02/01/2011 05:47 PM, Bruce Momjian wrote:
> >> Tom Lane wrote:
> >>> At this point what we've got is 25% of the runtime in nodeAgg.c overhead,
> >>> and it's difficult to see how to get any real improvement without tackling
> >>> that.
>
> >> Do we want a TODO about optimizing COUNT(*) to avoid aggregate
> >> processing overhead?
>
> > Whether or not it's bad application design, it's ubiquitous, and we
> > should make it work as best we can, IMNSHO. This often generates
> > complaints about Postgres, and if we really plan for world domination
> > this needs to be part of it.
>
> I don't think that saving ~25% on COUNT(*) runtime will help that at all.
> The people who complain about it expect it to be instantaneous.
>
> If this sort of hack were free, I'd be all for doing it anyway; but I'm
> concerned that adding tests to enable a fast path will slow down every
> other aggregate, or else duplicate a lot of code that we'll then have to
> maintain.

OK, thank you.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +