Re: ANALYZE sampling is too good

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От Claudio Freire
Тема Re: ANALYZE sampling is too good
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Msg-id CAGTBQpaRYAedJS=zJHnitiJj8pCFzoDR-FipuAwEoGEw1Ez=vw@mail.gmail.com
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Ответ на Re: ANALYZE sampling is too good  (Jeff Janes <jeff.janes@gmail.com>)
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On Thu, Dec 12, 2013 at 4:13 PM, Jeff Janes <jeff.janes@gmail.com> wrote:
>> Well, why not take a supersample containing all visible tuples from N
>> selected blocks, and do bootstrapping over it, with subsamples of M
>> independent rows each?
>
>
> Bootstrapping methods generally do not work well when ties are significant
> events, i.e. when two values being identical is meaningfully different from
> them being very close but not identical.

Yes, that's why I meant to say (but I see now that I didn't) that it
wouldn't do much for n_distinct, just the histogram.



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