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From: Tom Lane <tgl@sss.pgh.pa.us>
To: CN <cnliou9@fastmail.fm>
Cc: pgsql-sql@postgresql.org
Subject: Re: Creating Index
Date: Fri, 03 Oct 2003 11:26:23 -0400
Message-ID: <19818.1065194783@sss.pgh.pa.us> (raw)
In-Reply-To: <20031003041221.C45BB6475F@smtp.us2.messagingengine.com>
References: <20031002155005.943CD74F4F@smtp.us2.messagingengine.com>
	<29316.1065117519@sss.pgh.pa.us>
	<20031003020640.1562A74D53@smtp.us2.messagingengine.com>
	<20031003041221.C45BB6475F@smtp.us2.messagingengine.com>

"CN" <cnliou9@fastmail.fm> writes:
> I thought I have got no more question in this thread, and I was wrong :-(
> Is the extra 300ms in UNION essential?

Dividing, it looks like the Append node is taking about 3 microseconds
per tuple, which seems kind of a lot considering it isn't really doing
anything.  I suspect though that most of this overhead is due to the
EXPLAIN ANALYZE instrumentation, and would in fact go away when you
are just running the query.

			regards, tom lane

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