From: Tom Lane <tgl@sss.pgh.pa.us>
To: Michael Glaesemann <grzm@seespotcode.net>
Cc: pgsql-performance@postgresql.org
Subject: Re: EXPLAIN ANALYZE time calculations
Date: Sun, 02 Dec 2007 19:56:19 -0500
Message-ID: <239.1196643379@sss.pgh.pa.us> (raw)
In-Reply-To: <8C0EE80A-42A3-4CC1-850B-2A6B9220B422@seespotcode.net>
References: <8C0EE80A-42A3-4CC1-850B-2A6B9220B422@seespotcode.net>
Michael Glaesemann <grzm@seespotcode.net> writes:
> I'd like to get confirmation that I'm correctly understanding the
> times given in EXPLAIN ANALYZE.
> ...
> Is this correct?
Looks about right to me. Note that some of what you are calling
"executor overhead" might also be classed as "gettimeofday overhead".
The measured difference between two successive gettimeofday readings
presumably includes the actual userland runtime plus the equivalent
of one gettimeofday call; but we actually did two calls. IOW the
actual time to get in and out of a node is going to be a shade more
than is reported.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, grzm@seespotcode.net
Subject: Re: EXPLAIN ANALYZE time calculations
In-Reply-To: <239.1196643379@sss.pgh.pa.us>
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