Craig Ringer <craig.rin...@2ndquadrant.com> writes: > We're carefully maintaining this bizarre cognitive dissonance where we > justify the need for using this as a planner hint at the same time as > denying that we have a hint. That makes it hard to make progress here. > I think there's fear that we're setting some kind of precedent by > admitting what we already have.
I think you're overstating the case. It's clear that there's a significant subset of CTE functionality where there has to be an optimization fence. The initial implementation basically took the easy way out by deeming *all* CTEs to be optimization fences. Maybe we shouldn't have documented that behavior, but we did. Now we're arguing about how much of a compatibility break it'd be to change that planner behavior. I don't see any particular cognitive dissonance here, just disagreements about the extent to which backwards compatibility is more important than better query optimization. regards, tom lane -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers