Re: detecting poor query plans

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От Alvaro Herrera
Тема Re: detecting poor query plans
Дата
Msg-id 20031126173847.GA15041@dcc.uchile.cl
обсуждение исходный текст
Ответ на Re: detecting poor query plans  (Neil Conway <neilc@samurai.com>)
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On Wed, Nov 26, 2003 at 11:59:33AM -0500, Neil Conway wrote:

> > In some situations that doesn't really matter, as the same plan
> > would have gotten picked anyway.
> 
> The hint is NOT "the chosen plan was non-optimal"; the hint is "the
> query planner did not produce an accurate row count estimate for this
> node in the query tree."

Maybe it could only be done for SeqScan and IndexScan nodes, which are
probably the most common source of bad estimates related to poor
statistics.

-- 
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
"At least to kernel hackers, who really are human, despite occasional
rumors to the contrary" (LWN.net)


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