From: Tom Lane <tgl@sss.pgh.pa.us>
To: Jeremy Haile <jhaile@fastmail.fm>
Cc: pgsql-performance@postgresql.org
Subject: Re: Insert performance slows down in large batch
Date: Thu, 01 Dec 2005 14:19:14 -0500
Message-ID: <15960.1133464754@sss.pgh.pa.us> (raw)
In-Reply-To: <1133459351.23834.248779098@webmail.messagingengine.com>
References: <1133459351.23834.248779098@webmail.messagingengine.com>
"Jeremy Haile" <jhaile@fastmail.fm> writes:
> 1) Why does the performance degrade as the table sizes grow? Shouldn't
> the insert performance remain fairly constant if there are no indexes or
> constraints?
Yeah, insert really should be a constant-time operation if there's no
add-on operations like index updates or FK checks. Can you get more
information about where the time is going with gprof or oprofile?
(I'm not sure if oprofile is available for RHEL4, but it is in Fedora 4
so maybe RHEL4 has it too.)
If you're not comfortable with performance measurement tools, perhaps
you could crank up a test case program that just generates dummy data
and inserts it in the same way as your real application does. If you
can confirm a slowdown in a test case that other people can look at,
we'd be happy to look into the reason for it.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, jhaile@fastmail.fm
Subject: Re: Insert performance slows down in large batch
In-Reply-To: <15960.1133464754@sss.pgh.pa.us>
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