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Re: Wrong plan sequential scan instead of an index one

From: Gaetano Mendola <mendola(at)bigfoot(dot)com>
To: "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>
Cc: Michael Fuhr <mike(at)fuhr(dot)org>
Subject: Re: Wrong plan sequential scan instead of an index one
Date: 2007-03-30 11:35:00
Message-ID: 460CF5E4.3090005@bigfoot.com (view raw or flat)
Thread:
Lists: pgsql-performance
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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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Subject: Re: Wrong plan sequential scan instead of an index one
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