Re: Improving count(*)

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От Jim C. Nasby
Тема Re: Improving count(*)
Дата
Msg-id 20051121233349.GR19279@pervasive.com
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Ответ на Re: Improving count(*)  (Simon Riggs <simon@2ndquadrant.com>)
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On Fri, Nov 18, 2005 at 12:08:03AM +0000, Simon Riggs wrote:
> The trouble is, people moan and constantly. Perhaps we should stick to
> our guns and say, why do you care? From here, I think we should say,
> "show me an application package that needs this so badly we'll change
> PostgreSQL just for them". Prove it and we'll do it. Kinda polite in the
> TODO, but I think we should put something in there that says "things we
> haven't yet had any good reason to improve".

FWIW, this is one of Tom Kyte's (of http://asktom.oracle.com fame) big
complaints: if you have a query where count(*) isn't nearly instant then
you probably don't need an exact count in the first place and should be
happy enough with an estimate. He constantly cites Google ('Result 1-10
of about 38,923') as an example of this.
-- 
Jim C. Nasby, Sr. Engineering Consultant      jnasby@pervasive.com
Pervasive Software      http://pervasive.com    work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf       cell: 512-569-9461


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