From:
Simon Riggs <simon(at)2ndQuadrant(dot)com>
To:
Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
Cc:
Robert Haas <robertmhaas(at)gmail(dot)com>, Hannu Krosing <hannu(at)2ndquadrant(dot)com>,
greg(at)2ndquadrant(dot)com, Josh Berkus <josh(at)postgresql(dot)org>,
Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>,
pgsql-hackers(at)postgresql(dot)org
Subject:
Re: Sync Rep Design
Date:
2011-01-02 21:19:46
Message-ID:
1294003186.2090.3338.camel@ebony (view raw or flat )
Thread:
2010-12-30 17:26:12 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-30 17:42:22 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2010-12-30 19:04:13 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-30 20:07:16 from Robert Treat <rob(at)xzilla(dot)net>
2010-12-30 20:24:09 from Aidan Van Dyk <aidan(at)highrise(dot)ca>
2010-12-31 03:26:51 from Joshua Tolley <eggyknap(at)gmail(dot)com>
2010-12-31 11:51:55 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-30 20:36:30 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-30 20:51:19 from Robert Treat <rob(at)xzilla(dot)net>
2010-12-30 21:01:18 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-30 21:08:50 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2010-12-30 21:27:11 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-31 08:15:41 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2010-12-30 20:39:05 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-30 20:55:28 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-30 20:11:40 from Marti Raudsepp <marti(at)juffo(dot)org>
2010-12-30 21:10:00 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-30 20:42:23 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2010-12-30 21:23:55 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-31 08:27:29 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2010-12-31 10:26:11 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-31 12:33:19 from Aidan Van Dyk <aidan(at)highrise(dot)ca>
2010-12-31 16:56:38 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-01 13:13:07 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2011-01-01 14:03:35 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2011-01-01 14:15:45 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-01-01 15:12:19 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2011-01-01 16:55:57 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-01 17:13:24 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2011-01-01 17:29:20 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-01 17:49:44 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2011-01-01 19:03:30 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-01 16:35:59 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-02 20:27:10 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2010-12-30 21:47:42 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-12-31 01:15:10 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-31 01:57:34 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-31 05:02:13 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-12-31 07:50:43 from Hannu Krosing <hannu(at)2ndquadrant(dot)com>
2011-01-02 20:13:46 from MARK CALLAGHAN <mdcallag(at)gmail(dot)com>
2011-01-02 20:53:23 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-03 11:10:40 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-30 21:27:03 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-12-31 00:47:37 from Jim Nasby <jim(at)nasby(dot)net>
2010-12-31 01:38:32 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-31 01:07:53 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-31 07:50:07 from Hannu Krosing <hannu(at)2ndquadrant(dot)com>
2010-12-31 10:06:12 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2010-12-31 10:39:32 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2010-12-31 10:42:15 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-31 11:48:57 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-31 12:40:15 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-12-31 12:57:30 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2010-12-31 13:39:19 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-12-31 13:48:41 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2010-12-31 14:13:50 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-01-01 00:20:54 from Josh Berkus <josh(at)postgresql(dot)org>
2010-12-31 12:40:58 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2010-12-31 19:15:59 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-01 13:59:06 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2011-01-01 16:28:42 from Dimitri Fontaine <dimitri(at)2ndQuadrant(dot)fr>
2011-01-01 16:37:12 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2011-01-01 17:03:48 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-01 19:29:45 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2011-01-01 17:30:29 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-01 22:40:21 from Josh Berkus <josh(at)postgresql(dot)org>
2011-01-01 23:08:42 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-02 03:11:10 from Aidan Van Dyk <aidan(at)highrise(dot)ca>
2011-01-02 10:39:45 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-02 08:35:07 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2011-01-02 09:20:39 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2011-01-02 09:20:40 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-02 10:39:51 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-02 12:47:17 from Dimitri Fontaine <dimitri(at)2ndQuadrant(dot)fr>
2011-01-02 16:44:01 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2011-01-02 17:53:51 from Dimitri Fontaine <dimitri(at)2ndQuadrant(dot)fr>
2011-01-02 20:58:35 from Magnus Hagander <magnus(at)hagander(dot)net>
2011-01-02 21:24:27 from Dimitri Fontaine <dimitri(at)2ndQuadrant(dot)fr>
2011-01-04 18:40:25 from Josh Berkus <josh(at)postgresql(dot)org>
2011-01-04 22:00:53 from Dimitri Fontaine <dimitri(at)2ndQuadrant(dot)fr>
2011-01-04 22:18:13 from Josh Berkus <josh(at)postgresql(dot)org>
2011-01-04 22:24:43 from Dimitri Fontaine <dimitri(at)2ndQuadrant(dot)fr>
2011-01-04 23:20:21 from Josh Berkus <josh(at)agliodbs(dot)com>
2010-12-31 21:18:15 from Hannu Krosing <hannu(at)2ndquadrant(dot)com>
2011-01-01 11:54:35 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-02 04:36:10 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-01-02 10:59:32 from Hannu Krosing <hannu(at)2ndquadrant(dot)com>
2011-01-02 13:41:13 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-02 16:54:29 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2011-01-02 21:19:46 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-04 18:28:30 from Josh Berkus <josh(at)agliodbs(dot)com>
2011-01-04 18:51:45 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-04 19:04:21 from "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>
2011-01-04 19:50:17 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2011-01-04 19:54:04 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-01-05 01:59:57 from Greg Smith <greg(at)2ndquadrant(dot)com>
2011-01-04 19:04:37 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-01-03 01:30:12 from Hannu Krosing <hannu(at)2ndquadrant(dot)com>
2011-01-01 19:41:55 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2011-01-01 22:41:10 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
Lists:
pgsql-hackers
On Sun, 2011-01-02 at 18:54 +0200, Heikki Linnakangas wrote:
> I believe we all agree that there's different use cases that require
> different setups. Both "first-past-the-post" and "wait-for-all-to-ack"
> have their uses.
Robert's analysis is that "first-past-the-post" doesn't actually improve
the durability guarantee (according to his calcs). Which means that
1 primary, 2 sync standbys with first-past-the-post
is actually worse than
1 primary, 1 sync and 1 async standby
in terms of its durability guarantees.
So ISTM that Robert does not agree that both have their uses.
> I'm not
> sure what the point of such a timeout in general is, but people have
> requested that.
Again, this sounds like you think a timeout has no measurable benefit,
other than to please some people's perceived needs.
> The "wait-for-all-to-ack" looks a lot less ridiculous if you also
> configure a timeout and don't wait for disconnected standbys
Does it? Do Robert, Stefan and Aidan agree? What are the availability
and durability percentages if we do that? Based on those, we may decide
to do that instead. But I'd like to see some analysis of your ideas, not
just a "we could". Since nobody has commented on my analysis, lets see
someone else's.
> There's no point in arguing over which is better.
I'm trying to compare quantifiable benefit of various options to see
what goes into Postgres. I don't want to put anything in that we cannot
all agree has a measurable benefit to someone (that has the appropriate
preference).
--
Simon Riggs http://www.2ndQuadrant.com/books/
PostgreSQL Development, 24x7 Support, Training and Services
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