From: Chaz. <eprparadocs@gmail.com>
To: pgsql-sql@postgresql.org
Subject: Question about Sql SELECT and optimizer
Date: Thu, 02 Mar 2006 11:19:32 -0500
Message-ID: <44071B14.4060906@gmail.com> (raw)
I am trying to understand something I have seen happen. I had a select
that looked like:
select f(A) from A, B, C where g(A)
Where f(A) is the select that only depends on table A;
g(A) is the where part that only depends on table A.
What I saw happen was the optimizer will waste a lot of time (seconds!)
bringing in table B and C. I was wondering why doesn't the optimizer
drop references to tables B and C since they aren't used any where?
Peace and thanks in advance
Chuck Wegrzyn
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