Re: Custom/Foreign-Join-APIs (Re: [v9.5] Custom Plan API)

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От Robert Haas
Тема Re: Custom/Foreign-Join-APIs (Re: [v9.5] Custom Plan API)
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Msg-id CA+TgmobgJk08oUT2pb4L4RxxAdrgGU+CMp5CAXVfYRPhdsFNzA@mail.gmail.com
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Ответ на Re: Custom/Foreign-Join-APIs (Re: [v9.5] Custom Plan API)  (Shigeru HANADA <shigeru.hanada@gmail.com>)
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On Mon, Apr 27, 2015 at 5:05 AM, Shigeru HANADA
<shigeru.hanada@gmail.com> wrote:
> Currently INNER JOINs with unsafe join conditions are not pushed down, so such test is not in the suit.  As you say,
intheory, INNER JOINs can be pushed down even they have push-down-unsafe join conditions, because such conditions can
beevaluated no local side against rows retrieved without those conditions. 

I suspect it's worth trying to do the pushdown if there is at least
one safe joinclause.  If there are none, fetching a Cartesian product
figures to be a loser.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company



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