Re: [HACKERS] parallel "return query" is no good

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От Alvaro Herrera
Тема Re: [HACKERS] parallel "return query" is no good
Дата
Msg-id 20170323175359.nuuhobdyil7u4fvr@alvherre.pgsql
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Ответ на Re: [HACKERS] parallel "return query" is no good  (Robert Haas <robertmhaas@gmail.com>)
Ответы Re: parallel "return query" is no good  (Robert Haas <robertmhaas@gmail.com>)
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Robert Haas wrote:

> I guess the downside of back-patching this is that it could cause a
> plan change for somebody which ends up being worse.  On the whole,
> serial execution of queries intended to be run in parallel isn't
> likely to work out well, but it's always possible somebody has a cases
> where it happens to be winning, and this could break it.  So maybe I
> should do this only in master?  Thoughts?

I think that the chances of someone depending on a parallel plan running
serially by accident which is better than the non-parallel plan, are
pretty slim.

+1 for back-patching.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services



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