Re: BUG #4949: NOT IN is prohibitive slower than the rewrite for medium to large sets - Mailing list pgsql-bugs

From Tom Lane
Subject Re: BUG #4949: NOT IN is prohibitive slower than the rewrite for medium to large sets
Date
Msg-id 16400.1248788867@sss.pgh.pa.us
Whole thread Raw
In response to BUG #4949: NOT IN is prohibitive slower than the rewrite for medium to large sets  ("Ole Tange" <postgresql.org@tange.dk>)
Responses Re: BUG #4949: NOT IN is prohibitive slower than the rewrite for medium to large sets  (Ole Tange <ole@tange.dk>)
Re: BUG #4949: NOT IN is prohibitive slower than the rewrite for medium to large sets  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-bugs
"Ole Tange" <postgresql.org@tange.dk> writes:
> (modulo NULLs which seem to always cause problems in NOT INs).

> Because it can be rewritten, NOT IN should never be much slower than the
> rewritten solution, as PostgreSQL should simply rewrite NOT IN to the
> above.

Let's see, you understand that the rewrite violates the SQL standard
semantics of NOT IN, but you think we should do it anyway?

            regards, tom lane

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