From:
Jim Nasby <jim(at)nasby(dot)net>
To:
Kevin Grittner <kgrittn(at)ymail(dot)com>
Cc:
Christopher Browne <cbbrowne(at)gmail(dot)com>,
Andres Freund <andres(at)2ndquadrant(dot)com>,
Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>,
Heikki Linnakangas <hlinnakangas(at)vmware(dot)com>,
Pg Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject:
Re: autovacuum not prioritising for-wraparound tables
Date:
2013-01-30 22:44:34
Message-ID:
5109A252.6000108@nasby.net (view raw or flat )
Thread:
2013-01-24 21:57:15 from Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
2013-01-24 22:22:50 from Heikki Linnakangas <hlinnakangas(at)vmware(dot)com>
2013-01-24 23:25:47 from Christopher Browne <cbbrowne(at)gmail(dot)com>
2013-01-24 23:48:26 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-01-25 15:29:15 from Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
2013-01-25 15:49:25 from Peter Eisentraut <peter_e(at)gmx(dot)net>
2013-01-25 15:59:56 from Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
2013-01-25 16:44:49 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-01-25 16:51:33 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-01-25 17:00:51 from Andres Freund <andres(at)2ndquadrant(dot)com>
2013-01-25 17:56:46 from Christopher Browne <cbbrowne(at)gmail(dot)com>
2013-01-30 21:05:52 from Jim Nasby <jim(at)nasby(dot)net>
2013-01-30 21:28:36 from Kevin Grittner <kgrittn(at)ymail(dot)com>
2013-01-30 22:44:34 from Jim Nasby <jim(at)nasby(dot)net>
2013-01-30 22:37:33 from Christopher Browne <cbbrowne(at)gmail(dot)com>
2013-01-30 22:50:22 from Jim Nasby <jim(at)nasby(dot)net>
2013-01-31 19:36:47 from Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
2013-01-31 19:40:14 from Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
2013-01-31 19:54:31 from Robert Haas <robertmhaas(at)gmail(dot)com>
2013-01-31 20:18:24 from Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
2013-01-31 20:28:58 from Christopher Browne <cbbrowne(at)gmail(dot)com>
2013-02-01 21:59:52 from Robert Haas <robertmhaas(at)gmail(dot)com>
2013-02-01 22:43:04 from Christopher Browne <cbbrowne(at)gmail(dot)com>
2013-02-01 23:08:21 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-03-21 22:15:47 from Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
2013-02-02 13:41:35 from Andres Freund <andres(at)2ndquadrant(dot)com>
2013-02-02 16:25:01 from Robert Haas <robertmhaas(at)gmail(dot)com>
2013-02-02 18:49:13 from Andres Freund <andres(at)2ndquadrant(dot)com>
2013-02-02 19:54:10 from Robert Haas <robertmhaas(at)gmail(dot)com>
2013-02-02 21:03:54 from Andres Freund <andres(at)2ndquadrant(dot)com>
2013-02-03 02:08:34 from Christopher Browne <cbbrowne(at)gmail(dot)com>
2013-02-03 02:47:34 from Gavin Flower <GavinFlower(at)archidevsys(dot)co(dot)nz>
2013-02-28 17:21:58 from Jim Nasby <jim(at)nasby(dot)net>
2013-01-31 19:55:06 from Robert Haas <robertmhaas(at)gmail(dot)com>
2013-01-31 19:58:13 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-01-31 20:07:07 from Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
2013-01-25 17:19:25 from Robert Haas <robertmhaas(at)gmail(dot)com>
2013-01-25 17:35:25 from Andres Freund <andres(at)2ndquadrant(dot)com>
2013-01-25 17:52:46 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-01-25 18:01:16 from Andres Freund <andres(at)2ndquadrant(dot)com>
2013-01-25 18:02:19 from Robert Haas <robertmhaas(at)gmail(dot)com>
2013-01-25 18:17:20 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-01-25 19:22:50 from Robert Haas <robertmhaas(at)gmail(dot)com>
2013-01-27 19:33:18 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2013-01-27 09:17:27 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2013-01-27 17:11:53 from Robert Haas <robertmhaas(at)gmail(dot)com>
2013-01-27 21:29:56 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2013-01-27 19:17:24 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2013-01-29 03:03:19 from Robert Haas <robertmhaas(at)gmail(dot)com>
2013-01-25 00:18:32 from Andres Freund <andres(at)2ndquadrant(dot)com>
2013-01-28 13:11:12 from Josh Berkus <josh(at)agliodbs(dot)com>
2013-01-28 14:10:24 from Andres Freund <andres(at)2ndquadrant(dot)com>
2013-01-28 16:15:29 from Kevin Grittner <kgrittn(at)ymail(dot)com>
2013-01-28 16:21:15 from Andres Freund <andres(at)2ndquadrant(dot)com>
2013-02-02 04:48:48 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2013-01-29 05:09:52 from Josh Berkus <josh(at)agliodbs(dot)com>
2013-01-30 09:48:40 from Andres Freund <andres(at)2ndquadrant(dot)com>
2013-01-30 13:39:29 from Kevin Grittner <kgrittn(at)ymail(dot)com>
2013-01-30 13:58:24 from Andres Freund <andres(at)2ndquadrant(dot)com>
2013-01-30 14:55:21 from Andres Freund <andres(at)2ndquadrant(dot)com>
2013-01-30 18:21:07 from Kevin Grittner <kgrittn(at)ymail(dot)com>
2013-01-30 18:26:06 from Andres Freund <andres(at)2ndquadrant(dot)com>
2013-01-30 18:26:37 from Kevin Grittner <kgrittn(at)ymail(dot)com>
2013-02-01 15:17:25 from Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
2013-02-01 22:05:46 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2013-02-01 22:34:18 from Andres Freund <andres(at)2ndquadrant(dot)com>
2013-02-01 23:09:34 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2013-02-02 13:25:11 from Andres Freund <andres(at)2ndquadrant(dot)com>
2013-02-03 17:25:37 from Kevin Grittner <kgrittn(at)ymail(dot)com>
2013-02-03 22:58:43 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2013-02-04 21:59:57 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2013-02-04 22:16:02 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-02-02 15:43:43 from Robert Haas <robertmhaas(at)gmail(dot)com>
2013-02-03 01:40:04 from Andres Freund <andres(at)2ndquadrant(dot)com>
2013-02-03 01:41:42 from Andres Freund <andres(at)2ndquadrant(dot)com>
2013-02-03 16:17:42 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-02-03 16:41:20 from Andres Freund <andres(at)2ndquadrant(dot)com>
2013-02-03 18:26:25 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-02-03 21:08:35 from Andres Freund <andres(at)2ndquadrant(dot)com>
2013-01-30 15:58:07 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2013-01-30 18:31:50 from Kevin Grittner <kgrittn(at)ymail(dot)com>
2013-01-30 15:35:46 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2013-01-31 03:41:38 from Josh Berkus <josh(at)agliodbs(dot)com>
2013-01-29 03:35:22 from Robert Haas <robertmhaas(at)gmail(dot)com>
2013-01-27 20:47:20 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
Lists:
pgsql-hackers
On 1/30/13 3:28 PM, Kevin Grittner wrote:
> Jim Nasby <jim(at)nasby(dot)net> wrote:
>> then the *ideal* time to start a freeze vacuum on a table is so
>> that the vacuum would end *exactly* as we were about to hit XID
>> wrap.
>
> For a tuple which you know is going to survive long enough to be
> frozen, the *ideal* time to freeze a tuple, from a performance
> standpoint, is when the tuple is written, to eliminate a separate
> WAL-log operation. The *next best* time to freeze is when the hint
> bits are set, to avoid a separate page write. If you are doing
> differential backups, the *third best* time to freeze is before the
> first differential backup of the tuple, to avoid a separate backup
> after the freeze. And so on.
Yeah, I hadn't considered that aspect, but I think that's a separate
discussion. I agree that there are many cases where we would benefit
from freezing early, and those should all help reduce the impact of
XID-wrap induced freezing.
Even if we do introduce "up-front" freezing, we still need to deal with
all the other cases though, which in the worst case means avoiding the
XID wrap. I believe that particular case (as well as the whole autovac
priority question) would be best served by looking at 1st and 2nd order
derivatives.
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Next :From: Jim NasbyDate: 2013-01-30 22:50:22Subject : Re: autovacuum not prioritising for-wraparound tablesPrevious :From : MauMauDate : 2013-01-30 22:41:23Subject : Re: backend hangs at immediate shutdown (Re: Back-branch update releases coming in a couple weeks)
