Andrew Dunstan <andrew@dunslane.net> writes:
> Sufficient unto the day is the evil thereof. It seems premature to worry
> about it now.
Um, well, this whole thread is about how many potential optimizations
we're willing to toss aside to guarantee a particular behavior that the
current implementation has. So I think it's all about worrying about
the future.
One issue that just came to mind is what effect such a promise would
have on attempts to multi-thread the backend. I'm on record as being
dubious about the pain-to-reward ratio of any such attempt. But if
we ever do try it, the more constraints we've put on the order of row
processing, the less potential benefit there will be.
regards, tom lane