Re: index vs. seq scan choice?

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От Joshua D. Drake
Тема Re: index vs. seq scan choice?
Дата
Msg-id 46565086.2040705@commandprompt.com
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Ответ на Re: index vs. seq scan choice?  (Tom Lane <tgl@sss.pgh.pa.us>)
Ответы Re: index vs. seq scan choice?  (Tom Lane <tgl@sss.pgh.pa.us>)
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Tom Lane wrote:
> Alvaro Herrera <alvherre@commandprompt.com> writes:
>> Tom Lane wrote:
>>> (The default statistics target is 10, which is widely considered too
>>> low --- you might find 100 more suitable.)
>
>> Does this mean that we should look into raising the default a bit?
>
> Probably ... the question is to what.
>
> The default of 10 was chosen in our usual spirit of conservatism ---
> and IIRC it was replacing code that tracked only *one* most common
> value, so it was already a factor of 10 better (and more expensive)
> than what was there before.  But subsequent history suggests it's
> too small.  I'm not sure I want to vote for another 10x increase by
> default, though.

Outside of longer analyze times, and slightly more space taken up by the
statistics, what is the downside? I mean in reality... what is setting
to 100 going to do to effect actual production usage of even a modest
machine?

Sincerely,

Joshua D. Drake


>
>             regards, tom lane
>
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