Re: Wrong rows count estimation (explain, gist, tsearch)

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От Sergey Konoplev
Тема Re: Wrong rows count estimation (explain, gist, tsearch)
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Msg-id c3a7de1f0909280817u4b97aa38v78b4434b25eb0583@mail.gmail.com
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Ответ на Re: Wrong rows count estimation (explain, gist, tsearch)  (Tom Lane <tgl@sss.pgh.pa.us>)
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On Mon, Sep 28, 2009 at 6:26 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Sergey Konoplev <gray.ru@gmail.com> writes:
>> The table filled with about 7.5E+6 rows. Most of them have different
>> from default values in obj_tsvector column. I use "estimated rows
>> count trick" to make search results counter faster, and every time
>> when obj_tsvector is used estimation rows count is extremely differ
>> from actual (eg. 6821 vs 372012). I played with SET STATISTICS but
>> have no success.
>
> 8.3 has just a stub estimator for @@.  You might have better results
> with 8.4.  In the particular example you're showing, though, I don't
> think the poor rowcount estimate is making any difference to the
> plan choice.

Thanx, Tom. Will try 8.4

>
>                        regards, tom lane
>



--
Regards,
Sergey Konoplev
--
PostgreSQL articles in english & russian
http://gray-hemp.blogspot.com/search/label/postgresql/

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