Re: slow count in window query

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От Pavel Stehule
Тема Re: slow count in window query
Дата
Msg-id 162867790907160407u6bb86ac4n5e4bfacd674a8234@mail.gmail.com
обсуждение исходный текст
Ответ на Re: slow count in window query  (Greg Stark <gsstark@mit.edu>)
Ответы Re: slow count in window query  (Hitoshi Harada <umi.tanuki@gmail.com>)
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> I'm also not sure how to handle this if the set has to be spooled to
> disk. Quicksort and Quickselect do a lot of scans throught he data and
> wouldn't perform well on disk.

I thing, so problem is in aggregate func used as window func - or some
missing optimalisation.

when I replaced count(*) over () by subselect (SELECT count(*) FROM
...) then I got expected speed.

Pavel

>
> --
> greg
> http://mit.edu/~gsstark/resume.pdf
>


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