Re: Weird performance drop after VACUUM

From: "Steinar H(dot) Gunderson" <sgunderson(at)bigfoot(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Weird performance drop after VACUUM
Date: 2005-08-27 15:26:03
Message-ID: 20050827152603.GF17097@uio.no
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On Sat, Aug 27, 2005 at 11:05:01AM -0400, Tom Lane wrote:
> It could, but it doesn't really have enough information. We don't
> currently have any model that some operators are more expensive than
> others. IIRC the only sort of reordering the current code will do
> in a filter condition list is to push clauses involving sub-SELECTs
> to the end.

I was more thinking along the lines of reordering "a AND/OR b" to "b AND/OR
a" if b has lower selectivity than a.

/* Steinar */
--
Homepage: http://www.sesse.net/

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