Re: Lifting WHERE conditions out of inner select

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От John D. Burger
Тема Re: Lifting WHERE conditions out of inner select
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Msg-id 8BDE99A1-A6C9-4C2B-AC53-0F8C8F00DC7E@mitre.org
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Ответ на Re: Lifting WHERE conditions out of inner select  (Tom Lane <tgl@sss.pgh.pa.us>)
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Tom Lane wrote:

> The planner does not look for this type of situation though, and after
> some study I think it'd be more trouble than it was worth.  It'd be
> less than trivial to determine whether the upper references occurred
> only in places where it was safe to pull them up, and the actual
> pulling
> would take some code that doesn't exist now, too,

Okay, good to know.  The situation is obviously easy to avoid, I just
found the contrast surprising.

Thanks.

- John D. Burger
   MITRE



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