From: Martijn van Oosterhout <kleptog@svana.org>
To: Kevin Grittner <Kevin.Grittner@wicourts.gov>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-hackers@postgresql.org, pgsql-performance@postgresql.org, Andrea Olson <Aolson.CCAP.Courts@wicourts.gov>
Cc: Bill Severson <BSEVERS.CCAP.Courts@wicourts.gov>
Cc: John Hutchins <jhutchi.CCAP.Courts@wicourts.gov>
Cc: Randy Peterson <RPETERS.CCAP.Courts@wicourts.gov>
Cc: Shannon Spranger <ssprang.CCAP.Courts@wicourts.gov>
Subject: Re: EXISTS optimization
Date: Sat, 24 Mar 2007 14:07:59 +0100
Message-ID: <20070324130759.GA1089@svana.org> (raw)
In-Reply-To: <46040EB2.EE98.0025.0@wicourts.gov>
References: <4603C1A3.EE98.0025.0@wicourts.gov>
<25339.1174686582@sss.pgh.pa.us>
<20070323222641.GD9623@svana.org>
<46040EB2.EE98.0025.0@wicourts.gov>
On Fri, Mar 23, 2007 at 05:30:27PM -0500, Kevin Grittner wrote:
> I don't understand -- TRUE OR UNKNOWN evaluates to TRUE, so why would
> the IN need to continue? I'm not quite following the rest; could you
> elaborate or give an example? (Sorry if I'm lagging behind the rest
> of the class here.)
You're right, I'm getting confused with the interaction of NULL and NOT
IN.
The multiple evaluation thing still applies, but that's minor.
Have a nice day,
--
Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/> From each according to his ability. To each according to his ability to litigate.
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To: pgsql-performance@postgresql.org
Cc: kleptog@svana.org, Kevin.Grittner@wicourts.gov, tgl@sss.pgh.pa.us, Aolson.CCAP.Courts@wicourts.gov, BSEVERS.CCAP.Courts@wicourts.gov, jhutchi.CCAP.Courts@wicourts.gov, RPETERS.CCAP.Courts@wicourts.gov, ssprang.CCAP.Courts@wicourts.gov
Subject: Re: EXISTS optimization
In-Reply-To: <20070324130759.GA1089@svana.org>
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