Re: BUG #17826: An assert failed in /src/backend/optimizer/util/var.c

David Rowley <dgrowleyml(at)gmail(dot)com> writes:
> It is only possible to either leave such quals in the outer query in
> the WHERE clause or make them run conditions of some WindowClause in
> the subquery. They can never be legally in the WHERE clause of the
> subquery as window functions cannot be evaluated in the WHERE clause.

Ah, got it. So basically, the quals that we want are excluded by
check_output_expressions' point 4 (since they reference window
function output columns rather than partitioning columns). I think
we need them to satisfy every other property that's checked in this
code, though. Now I agree that we need to refactor a bit -- we
don't want to have to re-check all of these conditions.

regards, tom lane