From: Chris Browne <cbbrowne@acm.org>
To: pgsql-performance@postgresql.org
Subject: Re: BUG #2658: Query not using index
Date: Tue, 03 Oct 2006 15:18:36 -0400
Message-ID: <60d599gqcz.fsf@dba2.int.libertyrms.com> (raw)
References: <200609272056.k8RKuWjY040283@wwwmaster.postgresql.org>
<20061003000147.GA31475@wolff.to>
<4522AA01.4020709@refractions.net>
<60irj1gr3r.fsf@dba2.int.libertyrms.com>
<4522B5B9.2050206@refractions.net>
gdavis@refractions.net (Graham Davis) writes:
> 40 seconds is much too slow for this query to run and I'm assuming
> that the use of an index will make it much faster (as seen when I
> removed the GROUP BY clause). Any tips?
Assumptions are dangerous things.
An aggregate like this has *got to* scan the entire table, and given
that that is the case, an index scan is NOT optimal; a seq scan is.
An index scan is just going to be slower.
--
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To: pgsql-performance@postgresql.org
Cc: cbbrowne@acm.org
Subject: Re: BUG #2658: Query not using index
In-Reply-To: <60d599gqcz.fsf@dba2.int.libertyrms.com>
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