From: Steinar H. Gunderson <sgunderson@bigfoot.com>
To: pgsql-performance@postgresql.org
Subject: Re: Weird performance drop after VACUUM
Date: Sat, 27 Aug 2005 17:26:03 +0200
Message-ID: <20050827152603.GF17097@uio.no> (raw)
In-Reply-To: <1404.1125155101@sss.pgh.pa.us>
References: <1125093859.9329.30.camel@localhost.localdomain>
<26745.1125099111@sss.pgh.pa.us>
<20050827101945.GA18155@uio.no>
<1404.1125155101@sss.pgh.pa.us>
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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To: pgsql-performance@postgresql.org
Cc: sgunderson@bigfoot.com
Subject: Re: Weird performance drop after VACUUM
In-Reply-To: <20050827152603.GF17097@uio.no>
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