On 1/27/19 4:21 PM, Tom Lane wrote:
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.
+1
Andreas
