Andrew Gierth <and...@tao11.riddles.org.uk> writes: > I'm not sure we should nail down the rule that the absence of NOT > MATERIALIZED will mean a multiply-referenced CTE is evaluated once. One > would hope that in the future the planner might be taught to inline or > not in that case depending on cost. I think it makes more sense to say > that we never inline if MATERIALIZED is specified, that we always inline > if NOT MATERIALIZED is specified, and that if neither is specified the > planner will choose (but perhaps note that currently it always chooses > only based on refcount).
I have no objection to documenting it like that; I just don't want us to go off into the weeds trying to actually implement something smarter for v12. regards, tom lane