Re: Info about concurrent sequential scans

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От Bruce Momjian
Тема Re: Info about concurrent sequential scans
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Msg-id 201002221953.o1MJr7q04365@momjian.us
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Ответ на Info about concurrent sequential scans  (Daniele Varrazzo <daniele.varrazzo@gmail.com>)
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Daniele Varrazzo wrote:
> Hello,
>
> at Prato PgDay in 2007 I remember hearing in a speech about a (then
> yet to come) "seqscan piggyback" feature, allowing concurrent
> sequential scans to use the same disk reads. I've now googled for info
> about this feature, but I found nothing conclusive (e.g. [1], [2] -
> which I don't know where is linked).
>
> So I'd like to know:
>
> is this feature currently implemented (I'm specifically interested in PG 8.3)?
> Is there any prerequisite needed to benefit from it (config setting,
> query characteristic, etc.)?
> Is there any feedback showing the feature kicking in (e.g. an explain
> analyze output, log, etc.)?

The feature is called 'synchronize_seqscans' and was implemented in
Postgres 8.3.

--
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
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