Philippe Girolami <philippe(dot)girolami(at)sensorly(dot)com> writes:
> Hello,
> Using postgres 9.1.9, I have a view that uses a window function. I then query that view with a predicate on one of the columns. Unfortunately, the predicate doesn't get pushed down into the view.
> Given that the predicate applies to a column that's being partitionned on, why wouldn't the optimizer push the predicate down ?
Because there is zero optimization around window functions right now.
It certainly isn't smart enough to decide that it'd be safe to push
down a constraint that only mentions partitioning columns.
regards, tom lane