Gregory Stark <st...@enterprisedb.com> writes: > Tom Lane <t...@sss.pgh.pa.us> writes: >> Yeah. NOT IN does not have the right semantics to become an antijoin.
> If we noticed that the columns in the subquery are all guaranteed to be not > null could we do it then? I think you'd also have to know that the outer-query value isn't null, plus assume that the comparison operator can't return null for two non-nulls (but we already assume that for btree/hash equality I think). As you said, this would never have been safe before plan invalidation, but it might be doable now. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers