From: Stuart McGraw <smcg2297@frii.com>
To: pgsql-sql@postgresql.org
Subject: slowness when subselect uses DISTINCT
Date: Wed, 18 Apr 2007 12:16:37 -0600
Message-ID: <AKEFJAHAPDBEDKIICNJKMEOHCCAA.smcg2297@frii.com> (raw)
I have several times now run into what seems
like similar performance problems with some
of my postgresql queries.
I have a view that runs reasonably quicky.
I use this view in a subselect in another
query and that query too runs reasonably
quicky.
The view returns some unwanted duplicate
rows so I modify it using either DISTINCT
or GROUP BY to eliminate them.
View still runs reasonably quickly.
I use the modified view as a subselect as
above, but now the query runs 2-3 orders
of magnitude more slowly than before.
Before I go through the effort of putting
together a specific and concise test case,
has anyone seen this general pattern and
have an explanation or advice? (PG-8.2.3)
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To: pgsql-sql@postgresql.org
Cc: smcg2297@frii.com
Subject: Re: slowness when subselect uses DISTINCT
In-Reply-To: <AKEFJAHAPDBEDKIICNJKMEOHCCAA.smcg2297@frii.com>
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