Andrew Gierth <andrew@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