Overhead of union versus union all

From: Tim Keitt <tkeitt(at)keittlab(dot)org>
To: pgsql-general(at)postgresql(dot)org
Subject: Overhead of union versus union all
Date: 2009-07-08 19:31:17
Message-ID: 6262c54c0907081231r22c604f5sc83a3edf3d4188c0@mail.gmail.com
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I am combining query results that I know are disjoint. I'm wondering
how much overhead there is in calling union versus union all. (Just
curious really; I can't see a reason not to use union all.) (cc me
please; not subscribed...)

THK

--
Timothy H. Keitt
http://www.keittlab.org/

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