Re: Allowing join removals for more join types - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Allowing join removals for more join types
Date
Msg-id 27391.1402011871@sss.pgh.pa.us
Whole thread Raw
In response to Re: Allowing join removals for more join types  (Noah Misch <noah@leadboat.com>)
Responses Re: Allowing join removals for more join types  (Noah Misch <noah@leadboat.com>)
Re: Allowing join removals for more join types  (David Rowley <dgrowleyml@gmail.com>)
List pgsql-hackers
Noah Misch <noah@leadboat.com> writes:
> On Thu, Jun 05, 2014 at 02:12:33AM +0200, Andres Freund wrote:
>> A bit more crazy, but how about trying trying to plan joins with a added
>> one-time qual that checks the size of the deferred trigger queue? Then
>> we wouldn't even need special case plans.

> That, too, sounds promising to investigate.

Not terribly.  You can't actually do join removal in such a case, so it's
not clear to me that there's much win to be had.  The planner would be at
a loss as to what cost to assign such a construct, either.

Moreover, what happens if the trigger queue gets some entries after the
query starts?
        regards, tom lane



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