From: chester c young <chestercyoung@yahoo.com>
To: sql pgsql <pgsql-sql@postgresql.org>
Subject: do unneeded outer joins cost?
Date: Fri, 5 Jun 2009 08:01:51 -0700 (PDT)
Message-ID: <886808.30289.qm@web54302.mail.re2.yahoo.com> (raw)
for example:
select t1.*
from t1
left join t2 on( <expensive condition> );
since t2 is not used in the result nor is it used in determining the result, is the <expensive condition> to left join t2 used?
(the question goes as to how much generated sql needs to be cleaned to be efficient)
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To: pgsql-sql@postgresql.org
Cc: chestercyoung@yahoo.com
Subject: Re: do unneeded outer joins cost?
In-Reply-To: <886808.30289.qm@web54302.mail.re2.yahoo.com>
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