Re: count(*) performance improvement ideas

From: "Pavan Deolasee" <pavan(dot)deolasee(at)gmail(dot)com>
To: "Mark Mielke" <mark(at)mark(dot)mielke(dot)cc>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: count(*) performance improvement ideas
Date: 2008-03-12 16:59:48
Message-ID: 2e78013d0803120959r515667ecl4edb3bd3afbfbdfe@mail.gmail.com
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On Wed, Mar 12, 2008 at 9:53 PM, Mark Mielke <mark(at)mark(dot)mielke(dot)cc> wrote:
>
>
>
> Fine - once per transaction instead of once per insert. Still, if there is
> overhead to this (updating a secondary summary table), does it really make
> sense to have it for every table? Most of my tables do not require count(*)
> on the whole table (actually - none of them do). For the same reason as I
> don't want oid, I don't think I would want "fast count" capabilities to
> impact my regular queries. Again, I don't think count(*) on the whole table
> is a particularly useful case. count(*) on particular subsets of the data
> may be, but of the whole table?
>

ISTM that you are complaining because we never had an *fast* count(*)
and adding that now comes at a cost. Had it been there from day one with
the same overhead as we are talking about now, nobody would have
complained :-)

Anyways, your point is taken and it would be great if can make it configurable,
if not table level then at least globally.

Thanks,
Pavan

--
Pavan Deolasee
EnterpriseDB http://www.enterprisedb.com

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