Re: [PATCH] backend: compare word-at-a-time in bcTruelen

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От
Robert Haas
Тема
Re: [PATCH] backend: compare word-at-a-time in bcTruelen
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603c8f070906160503n42df8bafo26317e93ee5b5751@mail.gmail.com
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char() overhead on read-only workloads not so insignifcant as the docs claim it is... Stefan Kaltenbrunner <stefan@kaltenbrunner.cc>
Re: char() overhead on read-only workloads not so insignifcant as the docs claim it is... Gurjeet Singh <singh.gurjeet@gmail.com>
Re: char() overhead on read-only workloads not so insignifcant as the docs claim it is... Alvaro Herrera <alvherre@commandprompt.com>
[PATCH] backend: compare word-at-a-time in bcTruelen Jeremy Kerr <jk@ozlabs.org>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Stephen Frost <sfrost@snowman.net>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Robert Haas <robertmhaas@gmail.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Jeremy Kerr <jk@ozlabs.org>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Robert Haas <robertmhaas@gmail.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Simon Riggs <simon@2ndQuadrant.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Tom Lane <tgl@sss.pgh.pa.us>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Simon Riggs <simon@2ndQuadrant.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Alvaro Herrera <alvherre@commandprompt.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen "Kevin Grittner" <Kevin.Grittner@wicourts.gov>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Tom Lane <tgl@sss.pgh.pa.us>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Simon Riggs <simon@2ndQuadrant.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Greg Stark <gsstark@mit.edu>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Tom Lane <tgl@sss.pgh.pa.us>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen "Kevin Grittner" <Kevin.Grittner@wicourts.gov>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Stephen Frost <sfrost@snowman.net>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Robert Haas <robertmhaas@gmail.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Stephen Frost <sfrost@snowman.net>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Greg Stark <gsstark@mit.edu>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Tom Lane <tgl@sss.pgh.pa.us>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Simon Riggs <simon@2ndQuadrant.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Marko Kreen <markokr@gmail.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Simon Riggs <simon@2ndQuadrant.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Stefan Kaltenbrunner <stefan@kaltenbrunner.cc>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Simon Riggs <simon@2ndQuadrant.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Florian Weimer <fweimer@bfk.de>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Jeremy Kerr <jk@ozlabs.org>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Stefan Kaltenbrunner <stefan@kaltenbrunner.cc>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Jeremy Kerr <jk@ozlabs.org>
[PATCH] backend: compare word-at-a-time in bcTruelen Jeremy Kerr <jk@ozlabs.org>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Robert Haas <robertmhaas@gmail.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Jeremy Kerr <jk@ozlabs.org>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Robert Haas <robertmhaas@gmail.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Stefan Kaltenbrunner <stefan@kaltenbrunner.cc>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Stephen Frost <sfrost@snowman.net>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Jeremy Kerr <jk@ozlabs.org>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Tom Lane <tgl@sss.pgh.pa.us>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Jeremy Kerr <jk@ozlabs.org>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Dimitri Fontaine <dfontaine@hi-media.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Stephen Frost <sfrost@snowman.net>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Jeremy Kerr <jk@ozlabs.org>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Stephen Frost <sfrost@snowman.net>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Jeremy Kerr <jk@ozlabs.org>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Tom Lane <tgl@sss.pgh.pa.us>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Bruce Momjian <bruce@momjian.us>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Robert Haas <robertmhaas@gmail.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Alvaro Herrera <alvherre@commandprompt.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Stefan Kaltenbrunner <stefan@kaltenbrunner.cc>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Tom Lane <tgl@sss.pgh.pa.us>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Stefan Kaltenbrunner <stefan@kaltenbrunner.cc>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Tom Lane <tgl@sss.pgh.pa.us>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Bruce Momjian <bruce@momjian.us>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Dimitri Fontaine <dfontaine@hi-media.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen tomas@tuxteam.de
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Tom Lane <tgl@sss.pgh.pa.us>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen "Andrew Dunstan" <andrew@dunslane.net>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Stefan Kaltenbrunner <stefan@kaltenbrunner.cc>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Stephen Frost <sfrost@snowman.net>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Stefan Kaltenbrunner <stefan@kaltenbrunner.cc>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Stefan Kaltenbrunner <stefan@kaltenbrunner.cc>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Gurjeet Singh <singh.gurjeet@gmail.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Greg Stark <gsstark@mit.edu>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Jeremy Kerr <jk@ozlabs.org>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Robert Haas <robertmhaas@gmail.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Andrew Dunstan <andrew@dunslane.net>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Greg Stark <gsstark@mit.edu>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Stephen Frost <sfrost@snowman.net>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Chuck McDevitt <cmcdevitt@greenplum.com>
Re: [PATCH] backend: compare word-at-a-time in bcTruelen Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
Uninstallation error <genie.japo@gmail.com>
Re: Uninstallation error Peter Eisentraut <peter_e@gmx.net>
Re: Uninstallation error Alvaro Herrera <alvherre@commandprompt.com>
Re: Uninstallation error <genie.japo@gmail.com>
Re: char() overhead on read-only workloads not so insignifcant as the docs claim it is... Jeremy Kerr <jk@ozlabs.org>
On Tue, Jun 16, 2009 at 6:30 AM, Stephen Frost wrote:
> * Robert Haas (robertmhaas@gmail.com) wrote:
>> As I look at this, another problem is that it seems to me that you're
>> assuming that VARDATA_ANY() will return an aligned pointer, which
>> isn't necessarily the case (see src/include/postgres.h).
>
> I believe you need to look at it more carefully.  I don't think it's
> making any such assumption.  Specifically, it has three loops; an "until
> we're aligned" loop, then a "while we're aligned", and a "when we've
> done all the aligned we could do".

I see that... but I don't think the test in the first loop is correct.It's based on the value of i % 4, but I'm not convinced that you know
anything about the alignment at the point where i == 0.

I might be all wet here, I haven't looked at this area of the code in detail.

> On the flip side, I am curious as to if the arguments to a stored
> procedure are always aligned or not.  Never had a case to care before,
> but if palloc() is always going to return an aligned chunk of memory
> (per MemSetAligned in c.h) it makes me wonder.

Well, if it's char(n) for n <~ 126, it's going to have a 1-byte
varlena header...

...Robert

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