From: Tom Lane <tgl@sss.pgh.pa.us>
To: Kevin Grittner <Kevin.Grittner@wicourts.gov>
Cc: Robert Haas <robertmhaas@gmail.com>
Cc: JPalmer@linz.govt.nz
Cc: pgsql-performance@postgresql.org
Cc: andy@squeakycode.net
Subject: Re: Possible to improve query plan?
Date: Mon, 24 Jan 2011 12:33:34 -0500
Message-ID: <9658.1295890414@sss.pgh.pa.us> (raw)
In-Reply-To: <4D3D59810200002500039B05@gw.wicourts.gov>
References: <4D341E6802000025000396AF@gw.wicourts.gov>
<AANLkTi=xD9hJEbtdzzaKO9eNBDSY7WZk=y6Y2KshgPF+@mail.gmail.com>
<4D3D59810200002500039B05@gw.wicourts.gov>
"Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
> Robert Haas <robertmhaas@gmail.com> wrote:
>> But isn't 13.5 seconds awfully slow to scan 149557 rows? The sort
>> is sorting 23960kB. Dividing that by 149557 rows gives ~169
>> bytes/per row
> You're right. I would expect 9 ms as per tuple as a worst case if
> it doesn't need to go to TOAST data. Caching, multiple rows per
> page, or adjacent pages should all tend to bring it down from there.
> How does it get to 90 ms per row with rows that narrow?
Um, that looks like 90 usec per row, not msec.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, Kevin.Grittner@wicourts.gov, robertmhaas@gmail.com, JPalmer@linz.govt.nz, andy@squeakycode.net
Subject: Re: Possible to improve query plan?
In-Reply-To: <9658.1295890414@sss.pgh.pa.us>
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