From: Tom Lane <tgl@sss.pgh.pa.us>
To: Stephan Szabo <sszabo@megazone23.bigpanda.com>
Cc: Tomasz Myrta <jasiek@klaster.net>
Cc: Jan Wieck <JanWieck@Yahoo.com>
Cc: Ries van Twisk <ries@jongert.nl>
Cc: pgsql-sql@postgresql.org
Subject: Re: To use a VIEW or not to use a View.....
Date: Wed, 22 Jan 2003 20:01:20 -0500
Message-ID: <25948.1043283680@sss.pgh.pa.us> (raw)
In-Reply-To: <20030122164324.K4204-100000@megazone23.bigpanda.com>
References: <20030122164324.K4204-100000@megazone23.bigpanda.com>
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
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To: pgsql-sql@postgresql.org
Cc: tgl@sss.pgh.pa.us, sszabo@megazone23.bigpanda.com, jasiek@klaster.net, JanWieck@Yahoo.com, ries@jongert.nl
Subject: Re: To use a VIEW or not to use a View.....
In-Reply-To: <25948.1043283680@sss.pgh.pa.us>
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