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From: Dean Gibson (DB Administrator) <postgresql3@ultimeth.com>
To: pgsql-sql@postgresql.org
Subject: Re: JOIN performance
Date: Mon, 20 Sep 2004 21:41:40 -0700
Message-ID: <5.1.0.14.2.20040920213442.00ae4450@imaps.mailpen.net> (raw)
In-Reply-To: <25393.1095739813@sss.pgh.pa.us>
References: <5.1.0.14.2.20040920182022.00adf5e8@imaps.mailpen.net>
	<5.1.0.14.2.20040920164348.00a99868@imaps.mailpen.net>
	<5.1.0.14.2.20040920121606.00a89c68@imaps.mailpen.net>
	<414F02FF.8000603@numerixtechnology.de>
	<414F02FF.8000603@numerixtechnology.de>
	<5.1.0.14.2.20040920121606.00a89c68@imaps.mailpen.net>
	<5.1.0.14.2.20040920164348.00a99868@imaps.mailpen.net>
	<5.1.0.14.2.20040920182022.00adf5e8@imaps.mailpen.net>

It turns out that even when I removed the CASE statement from the VIEW, the 
performance problem remained.  I had to remove the conditional as well from 
the VIEW.

To refresh your memory, there was this line in the VIEW (said VIEW being 
the subject of the LEFT JOIN):

cancel_date < expire_date AS canceled,

(cancel_date & expire_date are DATEs in the base view)

When I removed the above line from the VIEW, the performance problem 
disappeared.

Do you know why?  I'm running 7.3.4, by the way.

-- Dean




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