From: Tom Lane <tgl@sss.pgh.pa.us>
To: Craig A. James <cjames@modgraph-usa.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Trivial function query optimized badly
Date: Thu, 04 Jan 2007 00:46:50 -0500
Message-ID: <12930.1167889610@sss.pgh.pa.us> (raw)
In-Reply-To: <459C705C.1060803@modgraph-usa.com>
References: <459C705C.1060803@modgraph-usa.com>
"Craig A. James" <cjames@modgraph-usa.com> writes:
> CREATE OR REPLACE FUNCTION cansmiles(text) RETURNS text
> AS '/usr/local/pgsql/lib/libchem.so', 'cansmiles'
> LANGUAGE 'C' STRICT IMMUTABLE;
Umm ... this is a single-argument function.
> db=> explain analyze select version_id, 'Brc1ccc2nc(cn2c1)C(=O)O' from version where version.isosmiles = cansmiles('Brc1ccc2nc(cn2c1)C(=O)O', 1);
And this query is invoking some other, two-argument function; which
apparently hasn't been marked IMMUTABLE, else it'd have been folded
to a constant.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, cjames@modgraph-usa.com
Subject: Re: Trivial function query optimized badly
In-Reply-To: <12930.1167889610@sss.pgh.pa.us>
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