Andres Freund <andres@anarazel.de> writes:
> I think we could just add a !contain_subplans() to the code deciding whether
> it's safe to use the movable window optimization?
Yeah, perhaps. That doesn't seem like a mainstream use-case either.
Another idea, tying into your previous point, is to try to check
contain_volatile_functions in the planner before we've reduced
sublinks to subplans. I'm not sure that would be convenient to do
though; subplan-conversion happens pretty early.
(I'm quite hesitant to move the goalposts on what
contain_volatile_functions detects. As that comment indicates,
some thought has gone into its current behavior, and I think
we might hit some unwanted side-effects if we change it.)
regards, tom lane