From: Tom Lane <tgl@sss.pgh.pa.us>
To: Don Drake <dondrake@gmail.com>
Cc: Stephan Szabo <sszabo@megazone.bigpanda.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: plpgsql functions and NULLs
Date: Mon, 31 Jan 2005 22:37:05 -0500
Message-ID: <9324.1107229025@sss.pgh.pa.us> (raw)
In-Reply-To: <6c21003b05013118121b464bac@mail.gmail.com>
References: <6c21003b0501301141234c256b@mail.gmail.com>
<20050131132701.G12960@megazone.bigpanda.com>
<6c21003b05013114272504d72e@mail.gmail.com>
<20050131162845.K27545@megazone.bigpanda.com>
<6c21003b05013118121b464bac@mail.gmail.com>
Don Drake <dondrake@gmail.com> writes:
> On Mon, 31 Jan 2005 16:32:02 -0800 (PST), Stephan Szabo
> <sszabo@megazone.bigpanda.com> wrote:
>> Actually, now that I think about it, I wonder if that's a good thing to
>> use because I don't think that'll use indexes to do the search. You may
>> want to do some testing to see how it runs for you.
> I'm constraining on other columns as well and it's still picking up the index.
Stephan is right that an IS DISTINCT FROM construct is not considered
indexable. So it's only your other constraints that are being used
with the index. You need to think about whether the other constraints
are selective enough to yield adequate performance.
regards, tom lane
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To: pgsql-sql@postgresql.org
Cc: tgl@sss.pgh.pa.us, dondrake@gmail.com, sszabo@megazone.bigpanda.com
Subject: Re: plpgsql functions and NULLs
In-Reply-To: <9324.1107229025@sss.pgh.pa.us>
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