From:
"Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
To:
"Andrew Dunstan" <andrew(at)dunslane(dot)net>, "Aidan Van Dyk" <aidan(at)highrise(dot)ca>
Cc:
"Simon Riggs" <simon(at)2ndquadrant(dot)com>, "Heikki Linnakangas" <heikki(dot)linnakangas(at)enterprisedb(dot)com>, <pgsql-hackers(at)postgresql(dot)org>
Subject:
Re: Re: [COMMITTERS] pgsql: Efficient transaction-controlled synchronous replication.
Date:
2011-03-07 15:13:46
Message-ID:
4D74A1CA020000250003B569@gw.wicourts.gov (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
Andrew Dunstan <andrew(at)dunslane(dot)net> wrote:
> 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.
So far, so good.
> Write is not considered complete until acknowledgement by both
> local and remote storage.
OK, *if* we want to live up to this definition, we don't seem to
have that part covered. Of course, since the connection is broken
during the hypothetical crash, it seems hard to acknowledge it on
recovery, and short of 2PC I don't see how we roll it back. About
the best we could do is somehow have explicit logging of the
disposition of unacknowledged commit requests upon recovery, and
consider logging of success to be "acknowledgement". Is this
logging provided by other databases with "synchronous replication"
features?
-Kevin
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