| 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 |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
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| 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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