Re: NOT IN subquery optimization - Mailing list pgsql-hackers

From Tom Lane
Subject Re: NOT IN subquery optimization
Date
Msg-id 5420.1551487529@sss.pgh.pa.us
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In response to Re: NOT IN subquery optimization  (David Rowley <david.rowley@2ndquadrant.com>)
Responses Re: NOT IN subquery optimization
Re: NOT IN subquery optimization
List pgsql-hackers
David Rowley <david.rowley@2ndquadrant.com> writes:
> I think you're fighting a losing battle here with adding OR quals to
> the join condition.

Yeah --- that has a nontrivial risk of making things significantly worse,
which makes it a hard sell.  I think the most reasonable bet here is
simply to not perform the transformation if we can't prove the inner side
NOT NULL.  That's going to catch most of the useful cases anyway IMO.

            regards, tom lane


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