From:
Andrew Dunstan <andrew(at)dunslane(dot)net>
To:
Aidan Van Dyk <aidan(at)highrise(dot)ca>
Cc:
Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>,
Simon Riggs <simon(at)2ndquadrant(dot)com>,
pgsql-hackers(at)postgresql(dot)org
Subject:
Re: Re: [COMMITTERS] pgsql: Efficient transaction-controlled
synchronous replication.
Date:
2011-03-07 15:03:10
Message-ID:
4D74F3AE.9000802@dunslane.net (view raw or flat )
Thread:
2011-03-06 22:51:56 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-03-06 23:09:53 from Andrew Dunstan <andrew(at)dunslane(dot)net>
2011-03-06 23:28:45 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-03-07 07:29:48 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2011-03-07 07:48:11 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-03-07 07:54:19 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2011-03-07 13:30:34 from Andrew Dunstan <andrew(at)dunslane(dot)net>
2011-03-07 14:02:44 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2011-03-07 14:21:46 from Andrew Dunstan <andrew(at)dunslane(dot)net>
2011-03-07 14:29:04 from Aidan Van Dyk <aidan(at)highrise(dot)ca>
2011-03-07 15:03:10 from Andrew Dunstan <andrew(at)dunslane(dot)net>
2011-03-07 15:13:46 from "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
2011-03-07 15:46:52 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2011-03-07 15:51:49 from Andrew Dunstan <andrew(at)dunslane(dot)net>
2011-03-07 16:09:49 from Alvaro Herrera <alvherre(at)commandprompt(dot)com>
2011-03-18 09:27:13 from Markus Wanner <markus(at)bluegap(dot)ch>
2011-03-18 13:16:24 from MARK CALLAGHAN <mdcallag(at)gmail(dot)com>
2011-03-18 13:30:56 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-03-18 13:40:22 from "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
2011-03-18 14:37:26 from Markus Wanner <markus(at)bluegap(dot)ch>
2011-03-18 16:03:03 from MARK CALLAGHAN <mdcallag(at)gmail(dot)com>
2011-03-18 14:19:18 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-03-18 14:52:13 from "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
2011-03-18 15:43:38 from Markus Wanner <markus(at)bluegap(dot)ch>
2011-03-18 15:47:46 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2011-03-18 16:19:31 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-03-18 16:33:26 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-03-18 16:48:57 from "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
2011-03-18 17:35:46 from Greg Stark <gsstark(at)mit(dot)edu>
2011-03-18 19:17:56 from Markus Wanner <markus(at)bluegap(dot)ch>
2011-03-18 19:19:06 from Markus Wanner <markus(at)bluegap(dot)ch>
2011-03-18 19:29:50 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-03-18 19:34:18 from "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
2011-03-18 19:41:00 from Markus Wanner <markus(at)bluegap(dot)ch>
2011-03-18 21:08:11 from Aidan Van Dyk <aidan(at)highrise(dot)ca>
2011-03-18 21:26:00 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-03-22 20:33:11 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-03-23 07:27:13 from Markus Wanner <markus(at)bluegap(dot)ch>
2011-03-23 11:52:22 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-03-23 12:16:39 from Markus Wanner <markus(at)bluegap(dot)ch>
2011-03-23 15:24:30 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-03-18 21:18:28 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-03-18 21:24:03 from "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
2011-03-18 21:30:04 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-03-18 21:43:32 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-03-18 21:48:33 from "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
2011-03-18 22:47:54 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-03-19 19:27:04 from Markus Wanner <markus(at)bluegap(dot)ch>
2011-03-25 12:12:05 from Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
2011-03-18 16:27:57 from "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
2011-03-18 19:22:20 from Markus Wanner <markus(at)bluegap(dot)ch>
2011-03-18 14:19:56 from Markus Wanner <markus(at)bluegap(dot)ch>
2011-03-18 15:52:18 from MARK CALLAGHAN <mdcallag(at)gmail(dot)com>
2011-03-07 15:04:22 from Aidan Van Dyk <aidan(at)highrise(dot)ca>
2011-03-07 14:55:11 from "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
2011-03-06 23:28:13 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2011-03-06 23:36:30 from Jaime Casanova <jaime(at)2ndquadrant(dot)com>
2011-03-06 23:38:30 from Jaime Casanova <jaime(at)2ndquadrant(dot)com>
2011-03-06 23:52:49 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-03-07 08:27:16 from Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
2011-03-07 08:44:52 from Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
2011-03-07 09:30:35 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-03-07 09:47:20 from Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
2011-03-10 21:28:12 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-03-18 14:10:03 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-03-19 01:12:52 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2011-03-23 15:53:30 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-03-07 09:20:07 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-03-07 09:28:25 from Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
2011-03-07 11:21:39 from Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
2011-03-10 20:04:57 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-03-11 10:46:03 from Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
2011-03-17 17:46:37 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-03-17 17:56:36 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-03-18 06:25:06 from Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
2011-03-18 12:25:49 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-03-18 14:55:56 from Greg Stark <gsstark(at)mit(dot)edu>
2011-03-18 15:07:23 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-03-18 15:40:57 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-03-25 11:53:15 from Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
2011-03-17 17:52:56 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-03-18 05:45:44 from Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
2011-03-18 07:52:07 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-03-18 12:16:08 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-03-10 20:44:33 from Robert Haas <robertmhaas(at)gmail(dot)com>
Lists:
pgsql-committers pgsql-hackers
On 03/07/2011 09:29 AM, Aidan Van Dyk wrote:
> On Mon, Mar 7, 2011 at 2:21 PM, Andrew Dunstan<andrew(at)dunslane(dot)net> wrote:
>
>>> For me, that's enough to call it "synchronous replication". It provides a
>>> useful guarantee to the client. But you could argue for an even stricter
>>> definition, requiring atomicity so that if a transaction is not successfully
>>> replicated for any reason, including crash, it is rolled back in the master
>>> too. That would require 2PC.
>>>
>> My worry is that the stricter definition is what many people will expect,
>> without reading the fine print.
> They they are either already hosed or already using 2PC.
>
>
This is about expectations. The thing that worries me is that the use of
this term might cause some people NOT to use 2PC because they think they
are getting an equivalent guarantee, when in fact they are not. And
that's hardly unreasonable. Here for example is what wikipedia says
<http://en.wikipedia.org/wiki/Replication_%28computer_science%29>:
Synchronous replication - guarantees "zero data loss" by the means
of atomic write operation, i.e. write either completes on both sides
or not at all. Write is not considered complete until
acknowledgement by both local and remote storage.
cheers
andrew
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