From: Michael Fuhr <mike@fuhr.org>
To: Gaetano Mendola <mendola@bigfoot.com>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Cc: Claus Guttesen <kometen@gmail.com>
Subject: Re: Wrong plan sequential scan instead of an index one
Date: Fri, 30 Mar 2007 04:55:34 -0600
Message-ID: <20070330105534.GA1737@winnie.fuhr.org> (raw)
In-Reply-To: <20070330104611.GA1540@winnie.fuhr.org>
References: <460CD941.6080303@bigfoot.com>
<b41c75520703300251oe916648r75c16c1bf70cd10@mail.gmail.com>
<460CE19A.3060909@bigfoot.com>
<20070330104611.GA1540@winnie.fuhr.org>
On Fri, Mar 30, 2007 at 04:46:11AM -0600, Michael Fuhr wrote:
> Have you tried increasing the statistics target on l_pvcp.value?
> I ran your queries against canned data in 8.2.3 and better statistics
> resulted in more accurate row count estimates for this and other
> parts of the plan. I don't recall if estimates for non-leading-character
> matches in earlier versions can benefit from better statistics.
This might work only in 8.2. I see the following in the Release Notes:
* Improve the optimizer's selectivity estimates for LIKE, ILIKE,
and regular expression operations (Tom)
--
Michael Fuhr
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To: pgsql-performance@postgresql.org
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Subject: Re: Wrong plan sequential scan instead of an index one
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