From: Gaetano Mendola <mendola@bigfoot.com>
To: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Cc: Michael Fuhr <mike@fuhr.org>
Subject: Re: Wrong plan sequential scan instead of an index one
Date: Fri, 30 Mar 2007 13:35:00 +0200
Message-ID: <460CF5E4.3090005@bigfoot.com> (raw)
In-Reply-To: <20070330105534.GA1737@winnie.fuhr.org>
References: <460CD941.6080303@bigfoot.com>
<b41c75520703300251oe916648r75c16c1bf70cd10@mail.gmail.com>
<460CE19A.3060909@bigfoot.com>
<20070330104611.GA1540@winnie.fuhr.org>
<20070330105534.GA1737@winnie.fuhr.org>
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Michael Fuhr wrote:
> 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)
I will try same select on a 8.2 ( that one was a 8.1 ) and I'll let you
know.
Regards
Gaetano Mendola
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To: pgsql-performance@postgresql.org
Cc: mendola@bigfoot.com, mike@fuhr.org
Subject: Re: Wrong plan sequential scan instead of an index one
In-Reply-To: <460CF5E4.3090005@bigfoot.com>
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