Re: Query that uses lots of memory in PostgreSQL 9.2.1 in Windows 7

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От Merlin Moncure
Тема Re: Query that uses lots of memory in PostgreSQL 9.2.1 in Windows 7
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Msg-id CAHyXU0yvvBmANx5ohmsGWK5iXT_cpLYf9-ey-iMsatsWJNYPdQ@mail.gmail.com
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Ответ на Re: Query that uses lots of memory in PostgreSQL 9.2.1 in Windows 7  (Pavel Stehule <pavel.stehule@gmail.com>)
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On Tue, Nov 20, 2012 at 1:27 AM, Pavel Stehule <pavel.stehule@gmail.com> wrote:
> Hello
>
> HashSetOp is memory expensive operation, and should be problematic
> when statistic estimation is bad.
>
> Try to rewritre this query to JOIN

or, 'WHERE NOT EXISTS'.   if 41 seconds seems like it's too long, go
ahead and post that plan and maybe that can be optimized.

merlin


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