From:
Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To:
Robert Haas <robertmhaas(at)gmail(dot)com>
Cc:
Simon Riggs <simon(at)2ndquadrant(dot)com>, Erik Rijkers <er(at)xs4all(dot)nl>,
Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>,
pgsql-hackers(at)postgresql(dot)org
Subject:
Re: testing HS/SR - 1 vs 2 performance
Date:
2010-04-25 15:50:17
Message-ID:
2867.1272210617@sss.pgh.pa.us (view raw or flat )
Thread:
2010-04-12 14:00:51 from "Erik Rijkers" <er(at)xs4all(dot)nl>
2010-04-13 05:44:19 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2010-04-13 18:09:46 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2010-04-14 08:24:45 from Dimitri Fontaine <dfontaine(at)hi-media(dot)com>
2010-04-14 12:08:13 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-16 08:29:54 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2010-04-16 09:10:01 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-16 11:47:42 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2010-04-16 12:00:22 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-16 21:00:09 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-16 14:39:52 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-16 14:52:49 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-16 15:10:45 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-17 14:16:55 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-17 15:13:46 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-17 15:25:46 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-04-17 19:20:00 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-17 19:45:47 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-17 20:14:33 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-17 20:48:21 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-17 22:46:06 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-17 22:52:26 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-18 07:24:36 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-18 11:01:05 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-18 20:16:11 from David Fetter <david(at)fetter(dot)org>
2010-04-18 20:22:21 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-18 20:23:21 from David Fetter <david(at)fetter(dot)org>
2010-04-20 11:50:23 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-04-21 03:09:43 from Mark Kirkwood <mark(dot)kirkwood(at)catalyst(dot)net(dot)nz>
2010-04-21 03:46:06 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-04-21 06:39:16 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-21 12:20:32 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2010-04-21 13:31:28 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-21 14:11:00 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-04-21 12:27:12 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2010-04-21 13:37:46 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-21 13:51:00 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-04-21 14:12:43 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-21 14:22:50 from marcin mank <marcin(dot)mank(at)gmail(dot)com>
2010-04-21 14:49:06 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-21 15:13:29 from Florian Pflug <fgp(at)phlo(dot)org>
2010-04-21 14:53:05 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-04-22 05:57:43 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2010-04-22 06:56:39 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-22 18:39:14 from "Erik Rijkers" <er(at)xs4all(dot)nl>
2010-04-22 21:41:29 from Greg Smith <greg(at)2ndquadrant(dot)com>
2010-04-22 21:54:55 from Mark Kirkwood <mark(dot)kirkwood(at)catalyst(dot)net(dot)nz>
2010-04-22 22:32:44 from "Erik Rijkers" <er(at)xs4all(dot)nl>
2010-04-22 22:45:47 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-23 15:14:41 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-23 15:32:19 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-04-23 22:39:48 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-23 23:07:15 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-04-24 09:17:44 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-25 10:53:04 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-04-25 12:50:00 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-25 15:37:04 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-04-25 15:50:17 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-25 16:46:38 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-25 16:51:58 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-25 17:00:58 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-25 17:33:24 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-25 17:45:02 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-25 17:51:00 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-27 02:35:22 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-27 02:37:18 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-27 17:52:50 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-27 18:13:33 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-27 18:53:16 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-27 19:29:13 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-27 20:18:53 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-27 20:44:32 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-27 21:24:48 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-27 21:45:53 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-27 22:08:29 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-27 22:45:54 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-28 00:13:09 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-28 09:37:38 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-23 23:17:22 from "Erik Rijkers" <er(at)xs4all(dot)nl>
2010-04-25 18:25:16 from "Erik Rijkers" <er(at)xs4all(dot)nl>
2010-04-25 18:55:02 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-25 21:52:19 from "Erik Rijkers" <er(at)xs4all(dot)nl>
2010-04-26 07:43:09 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-26 15:04:09 from "Erik Rijkers" <er(at)xs4all(dot)nl>
2010-04-25 19:07:28 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-05-04 16:10:53 from "Erik Rijkers" <er(at)xs4all(dot)nl>
2010-05-04 16:19:47 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-05-04 16:33:26 from "Erik Rijkers" <er(at)xs4all(dot)nl>
2010-05-04 18:26:58 from Greg Smith <greg(at)2ndquadrant(dot)com>
2010-05-04 19:40:12 from "Erik Rijkers" <er(at)xs4all(dot)nl>
2010-05-07 12:04:02 from Greg Smith <greg(at)2ndquadrant(dot)com>
2010-05-04 19:34:53 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2010-05-04 20:48:07 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-26 06:52:51 from Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
2010-04-26 15:01:41 from "Erik Rijkers" <er(at)xs4all(dot)nl>
2010-04-23 00:44:11 from Mark Kirkwood <mark(dot)kirkwood(at)catalyst(dot)net(dot)nz>
2010-04-25 16:43:57 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-25 16:54:59 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-25 23:18:48 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-26 07:21:35 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-04-23 17:16:09 from Marko Kreen <markokr(at)gmail(dot)com>
2010-04-23 17:38:48 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2010-04-23 18:22:55 from Marko Kreen <markokr(at)gmail(dot)com>
Lists:
pgsql-hackers
Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Sat, Apr 24, 2010 at 5:17 AM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> Both Heikki and I objected to that patch.
>>
>> Please explain your objection, based upon the patch and my explanations.
> Well, we objected to the locking.
Not only is the locking overly complex, but it's outright wrong;
or at least the comments are. KnownAssignedXidsAdd in particular
has a comment that is 100% misleading, and an actual behavior that
I find extremely likely to provoke bugs (eg, consider caller calling
it twice under the illusion it stlll has only shared lock). I'm not
even convinced that it works correctly, since it will happily write
into KnownAssignedXids[] while holding only shared ProcArrayLock.
What happens when two processes are doing that concurrently?
This needs a redesign before it can be considered committable. I don't
really care whether it makes things faster; it's too complicated and too
poorly documented to be maintainable.
regards, tom lane
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