Re: GiST, caching, and consistency

От: Tom Lane
Тема: Re: GiST, caching, and consistency
Дата: ,
Msg-id: 9731.1249481514@sss.pgh.pa.us
(см: обсуждение, исходный текст)
Ответ на: Re: GiST, caching, and consistency  (Matthew Wakeling)
Список: pgsql-performance

Скрыть дерево обсуждения

GiST, caching, and consistency  (Matthew Wakeling, )
 Re: GiST, caching, and consistency  (Robert Haas, )
  Re: GiST, caching, and consistency  (Greg Stark, )
   Re: GiST, caching, and consistency  (Matthew Wakeling, )
    Re: GiST, caching, and consistency  (Robert Haas, )
     Re: GiST, caching, and consistency  (Matthew Wakeling, )
    Re: GiST, caching, and consistency  (Tom Lane, )

Matthew Wakeling <> writes:
> It is certainly doing a sequential scan. So are you saying that it will
> start a sequential scan from a different part of the table each time, even
> in the absence of other simultaneous sequential scans?

Yeah, that's the syncscan logic biting you.  You can turn it off if you
want.

> Some trivial testing with "select * from location limit 10;" indicates
> that it starts the sequential scan in the same place each time - but is
> this different from the above query?

Yup, you're not scanning enough of the table to move the syncscan start
pointer.

            regards, tom lane


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