From:
Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To:
Simon Riggs <simon(at)2ndquadrant(dot)com>
Cc:
Alvaro Herrera <alvherre(at)commandprompt(dot)com>,
Gregory Maxwell <gmaxwell(at)gmail(dot)com>, Greg Stark <gsstark(at)mit(dot)edu>,
Christopher Kings-Lynne <chriskl(at)familyhealth(dot)com(dot)au>,
pgsql-hackers(at)postgresql(dot)org
Subject:
Re: Reducing relation locking overhead
Date:
2005-12-02 22:45:10
Message-ID:
8413.1133563510@sss.pgh.pa.us (view raw or flat )
Thread:
2005-12-02 02:37:47 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-12-02 02:45:02 from Christopher Kings-Lynne <chriskl(at)familyhealth(dot)com(dot)au>
2005-12-02 03:03:33 from Stephen Frost <sfrost(at)snowman(dot)net>
2005-12-02 06:44:08 from Greg Stark <gsstark(at)mit(dot)edu>
2005-12-02 07:14:37 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-12-02 14:53:27 from Simon Riggs <simon(at)2ndquadrant(dot)com>
2005-12-02 20:25:58 from Greg Stark <gsstark(at)mit(dot)edu>
2005-12-02 21:01:39 from Gregory Maxwell <gmaxwell(at)gmail(dot)com>
2005-12-02 22:04:23 from Alvaro Herrera <alvherre(at)commandprompt(dot)com>
2005-12-02 22:34:57 from Simon Riggs <simon(at)2ndquadrant(dot)com>
2005-12-02 22:45:10 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-12-03 09:10:54 from Simon Riggs <simon(at)2ndquadrant(dot)com>
2005-12-03 15:15:25 from Greg Stark <gsstark(at)mit(dot)edu>
2005-12-03 15:47:26 from Kevin Brown <kevin(at)sysexperts(dot)com>
2005-12-03 16:57:49 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-12-03 17:09:53 from Kevin Brown <kevin(at)sysexperts(dot)com>
2005-12-03 17:53:44 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-12-04 03:38:28 from "Qingqing Zhou" <zhouqq(at)cs(dot)toronto(dot)edu>
2005-12-04 03:51:12 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-12-04 17:13:28 from Kevin Brown <kevin(at)sysexperts(dot)com>
2005-12-04 18:32:56 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-12-04 20:15:37 from Kevin Brown <kevin(at)sysexperts(dot)com>
2005-12-05 03:07:38 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-12-05 06:40:55 from Kevin Brown <kevin(at)sysexperts(dot)com>
2005-12-05 13:38:17 from mark(at)mark(dot)mielke(dot)cc
2005-12-05 14:47:43 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-12-05 15:08:55 from Alvaro Herrera <alvherre(at)commandprompt(dot)com>
2005-12-05 16:28:43 from Kevin Brown <kevin(at)sysexperts(dot)com>
2005-12-05 01:27:03 from Greg Stark <gsstark(at)mit(dot)edu>
2005-12-03 16:29:43 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-12-08 06:16:42 from "Jim C(dot) Nasby" <jim(at)nasby(dot)net>
2005-12-08 06:57:42 from Hannu Krosing <hannu(at)skype(dot)net>
2005-12-08 07:08:10 from "Jim C(dot) Nasby" <jim(at)nasby(dot)net>
2005-12-08 09:58:50 from Hannu Krosing <hannu(at)skype(dot)net>
2005-12-08 18:57:02 from "Jim C(dot) Nasby" <jim(at)nasby(dot)net>
2005-12-08 22:00:14 from Hannu Krosing <hannu(at)skype(dot)net>
2005-12-08 23:03:21 from "Jim C(dot) Nasby" <jnasby(at)pervasive(dot)com>
2006-03-03 03:12:59 from Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
2006-03-03 22:46:39 from "Jim C(dot) Nasby" <jnasby(at)pervasive(dot)com>
2006-03-04 05:02:06 from Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
2005-12-02 22:41:15 from Jochem van Dieten <jochemd(at)gmail(dot)com>
2005-12-02 23:32:57 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-12-03 21:45:14 from Jochem van Dieten <jochemd(at)gmail(dot)com>
2005-12-03 15:23:06 from Greg Stark <gsstark(at)mit(dot)edu>
2005-12-03 16:30:31 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-12-03 19:01:02 from Greg Stark <gsstark(at)mit(dot)edu>
2005-12-08 06:04:59 from "Jim C(dot) Nasby" <jim(at)nasby(dot)net>
2005-12-03 13:47:36 from Robert Treat <xzilla(at)users(dot)sourceforge(dot)net>
2005-12-03 19:39:53 from Simon Riggs <simon(at)2ndquadrant(dot)com>
2005-12-03 20:16:27 from Alvaro Herrera <alvherre(at)commandprompt(dot)com>
2005-12-03 23:32:17 from Simon Riggs <simon(at)2ndquadrant(dot)com>
2005-12-08 20:34:03 from Ron Mayer <rm_pg(at)cheapcomplexdevices(dot)com>
2005-12-05 14:03:30 from Hannu Krosing <hannu(at)skype(dot)net>
2005-12-06 19:50:45 from Jochem van Dieten <jochemd(at)gmail(dot)com>
2005-12-06 20:12:40 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-12-06 20:29:27 from Hannu Krosing <hannu(at)skype(dot)net>
2005-12-06 20:41:28 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-12-06 20:58:06 from Hannu Krosing <hannu(at)skype(dot)net>
2005-12-06 21:01:57 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-12-06 21:07:45 from Hannu Krosing <hannu(at)skype(dot)net>
2005-12-07 18:01:35 from Jochem van Dieten <jochemd(at)gmail(dot)com>
2005-12-06 20:26:02 from Hannu Krosing <hannu(at)skype(dot)net>
2005-12-06 20:38:38 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-12-06 20:45:31 from Hannu Krosing <hannu(at)skype(dot)net>
2005-12-07 00:32:30 from Greg Stark <gsstark(at)mit(dot)edu>
2005-12-07 07:43:08 from Hannu Krosing <hannu(at)skype(dot)net>
2005-12-07 18:36:07 from Greg Stark <gsstark(at)mit(dot)edu>
2005-12-07 20:33:13 from Hannu Krosing <hannu(at)skype(dot)net>
2005-12-08 10:05:17 from Csaba Nagy <nagy(at)ecircle-ag(dot)com>
2005-12-08 09:14:34 from Simon Riggs <simon(at)2ndquadrant(dot)com>
2005-12-08 15:05:15 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-12-08 15:23:57 from Csaba Nagy <nagy(at)ecircle-ag(dot)com>
2005-12-08 18:25:26 from Simon Riggs <simon(at)2ndquadrant(dot)com>
2005-12-08 19:53:24 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-12-11 01:55:38 from Hannu Krosing <hannu(at)skype(dot)net>
2005-12-11 02:07:44 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-12-11 13:28:10 from Simon Riggs <simon(at)2ndquadrant(dot)com>
2005-12-11 18:33:57 from Hannu Krosing <hannu(at)skype(dot)net>
2005-12-12 14:02:50 from Alvaro Herrera <alvherre(at)commandprompt(dot)com>
Lists:
pgsql-hackers
Simon Riggs <simon(at)2ndquadrant(dot)com> writes:
> CREATE INDEX uses SnapshotAny, so the scan that feeds the build could
> easily include rows added after the CREATE INDEX started. When the scan
> was exhausted we could mark that last TID and return to it after the
> sort/build.
And do what? This has nothing to do with the fundamental problem of
never being able to catch up unless you can upgrade your lock to exclude
writes. What's worse, once you have excluded writes you have to rescan
the entire table to be sure you haven't missed anything. So in the
scenarios where this whole thing is actually interesting, ie enormous
tables, you're still talking about a fairly long interval with writes
locked out. Maybe not as long as a complete REINDEX, but long.
regards, tom lane
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