Re: PostgreSQL reads each 8k block - no larger blocks are used - even on sequential scans

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От Sam Mason
Тема Re: PostgreSQL reads each 8k block - no larger blocks are used - even on sequential scans
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Msg-id 20090927211942.GU5407@samason.me.uk
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Ответ на Re: PostgreSQL reads each 8k block - no larger blocks are used - even on sequential scans  (Sam Mason <sam@samason.me.uk>)
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On Sun, Sep 27, 2009 at 10:01:27PM +0100, Sam Mason wrote:
> Tested by turning on "\timing" mode in psql, dropping
> caches and running:
>
>   SELECT 715833344 / 7597.216 / 1024;

Help, I can't do maths!  This is overestimating the performance and
should be:

  SELECT 715833344 / 7597.216 / 1024 / 1024 * 1000;

After a few more runs to increase confidence, the read performance is
87.17 and a stddev of 2.8.  Which seems more reasonable, it should *not*
be going above 90MB/s as often as it was.

--
  Sam  http://samason.me.uk/

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