Re: GiST, caching, and consistency - Mailing list pgsql-performance

From Tom Lane
Subject Re: GiST, caching, and consistency
Date
Msg-id 9731.1249481514@sss.pgh.pa.us
Whole thread Raw
In response to Re: GiST, caching, and consistency  (Matthew Wakeling <matthew@flymine.org>)
List pgsql-performance
Matthew Wakeling <matthew@flymine.org> 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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