From: Andrus <kobruleht2@hot.ee>
To: pgsql-performance@postgresql.org
Subject: analyzing intermediate query
Date: Tue, 2 Dec 2008 14:06:36 +0200
Message-ID: <gh38cg$1544$1@news.hub.org> (raw)
I noticed that query
SELECT dok.*
FROM dok
JOIN (SELECT DISTINCT dokumnr FROM temptbl ) x USING(dokumnr);
is slow in 8.1.4
I cannot use explain analyze since this query uses results from temporary
table temptbl which is not available.
Sometimes innter table returns only 1 row so maybe seq scan is selected
instead of single row index access becauses expected count is 1000
As I understand, PostgreSql requires manually running ANALYZE for temporary
tables if their row count is different from 1000
How to force PostgreSql to analyze inner table in this query or use other
way to get index using query plan if inner query returns single row ?
How
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To: pgsql-performance@postgresql.org
Cc: kobruleht2@hot.ee
Subject: Re: analyzing intermediate query
In-Reply-To: <gh38cg$1544$1@news.hub.org>
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