Re: Slow counting still true?

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От Chris Travers
Тема Re: Slow counting still true?
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Msg-id CAKt_Zfs+45uD8VeVMx_U-r_+-CthY6ka7AMDn4YGNGeZJg8Wyw@mail.gmail.com
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Ответ на Slow counting still true?  (Thomas Guettler <hv@tbz-pariv.de>)
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On Mon, Sep 17, 2012 at 1:07 AM, Thomas Guettler <hv@tbz-pariv.de> wrote:
Release 9.2 should increase count(*) performance. Is this wiki page still valid?

http://wiki.postgresql.org/wiki/Slow_Counting

Please update the content.

As I understand it, covering indexes don't currently help with count(*) because indexes can't be traversed in physical order, so it is a matter of trading random disk I/O for a much larger amount of sequential disk I/O.

Best Wishes,
Chris Travers

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