Stephan Szabo <sszabo@megazone23.bigpanda.com> writes:
> On Wed, 22 Jan 2003, Tom Lane wrote:
>> Stephan Szabo <sszabo@megazone23.bigpanda.com> writes:
>>> The filter is applied only to a. So, if you really wanted the
>>> c.a=3 condition to be applied for whatever reason you're out of
>>> luck.
>>
>> FWIW, CVS tip is brighter: the condition does propagate to both relations.
> Yeah. I was going to ask how hard you thought it would be to do for
> this particular sort of case. I thought about the simple case of using
> and realized it'd probably be reasonable in amount of work, but it seems
> I don't have to think about it. :)
It could still use more eyeballs looking at it. One thing I'm concerned
about is whether the extra (derived) conditions lead to double-counting
restrictivity and thus underestimating the number of result rows. I
haven't had time to really test that, but I suspect there may be a problem.
regards, tom lane