On Thu, Nov 13, 2008 at 5:16 AM, Tom Lane <[EMAIL PROTECTED]> wrote: > "Brendan Jurd" <[EMAIL PROTECTED]> writes: >> I guess my question is, what's the real benefit of going to all this >> trouble trying to prove that clauses are false? > > Not having to scan gigabytes of data in an excluded partition, for > instance.
[after RTFMing ...] The docs also say: "When this parameter is on, the planner compares query conditions with table CHECK constraints, and omits scanning tables for which the conditions contradict the constraints." I would normally interpret the above to mean that the planner *only* performs these checks where a table CHECK constraint is relevant. I dug up the original test case posted by Sergey, and his test table didn't have any CHECK constraint on it at all (unless you count the NOT NULL implied by PRIMARY KEY). Cheers, BJ -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
