From:
Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To:
Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
Cc:
"Jonah H(dot) Harris" <jharris(at)tvi(dot)edu>, pgsql-hackers(at)postgresql(dot)org
Subject:
Re: Much Ado About COUNT(*)
Date:
2005-01-13 04:54:52
Message-ID:
5213.1105592092@sss.pgh.pa.us (view raw or flat )
Thread:
2005-01-11 20:15:41 from "Marc G(dot) Fournier" <scrappy(at)postgresql(dot)org>
2005-01-12 08:23:57 from Simon Riggs <simon(at)2ndquadrant(dot)com>
2005-01-12 08:53:43 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-01-12 10:38:55 from Reinhard Max <max(at)suse(dot)de>
2005-01-12 10:17:52 from Reinhard Max <max(at)suse(dot)de>
2005-01-12 15:29:23 from Peter Eisentraut <peter_e(at)gmx(dot)net>
2005-01-12 16:29:34 from Reinhard Max <max(at)suse(dot)de>
2005-01-12 17:20:14 from Reinhard Max <max(at)suse(dot)de>
2005-01-12 17:42:56 from "Jonah H(dot) Harris" <jharris(at)tvi(dot)edu>
2005-01-12 18:24:26 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-01-12 18:55:29 from "Jonah H(dot) Harris" <jharris(at)tvi(dot)edu>
2005-01-12 19:23:44 from Greg Stark <gsstark(at)mit(dot)edu>
2005-01-12 19:36:15 from "Jonah H(dot) Harris" <jharris(at)tvi(dot)edu>
2005-01-12 20:08:37 from Greg Stark <gsstark(at)mit(dot)edu>
2005-01-12 20:41:38 from Jeff Davis <jdavis-pgsql(at)empires(dot)org>
2005-01-12 21:43:46 from Alvaro Herrera <alvherre(at)dcc(dot)uchile(dot)cl>
2005-01-13 02:45:09 from Jeff Davis <jdavis-pgsql(at)empires(dot)org>
2005-01-13 03:19:18 from Greg Stark <gsstark(at)mit(dot)edu>
2005-01-13 03:50:57 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-01-12 21:42:06 from "Marek Mosiewicz" <marekmosiewicz(at)poczta(dot)onet(dot)pl>
2005-01-12 19:41:56 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-01-12 19:52:53 from "Jonah H(dot) Harris" <jharris(at)tvi(dot)edu>
2005-01-12 20:09:04 from Rod Taylor <pg(at)rbt(dot)ca>
2005-01-12 20:59:07 from "Jonah H(dot) Harris" <jharris(at)tvi(dot)edu>
2005-01-12 21:45:51 from Simon Riggs <simon(at)2ndquadrant(dot)com>
2005-01-12 21:58:14 from "Jonah H(dot) Harris" <jharris(at)tvi(dot)edu>
2005-01-12 22:03:58 from Rod Taylor <pg(at)rbt(dot)ca>
2005-01-12 20:14:51 from "Andrew Dunstan" <andrew(at)dunslane(dot)net>
2005-01-12 20:42:58 from "Jonah H(dot) Harris" <jharris(at)tvi(dot)edu>
2005-01-12 21:02:23 from Jon Jensen <jon(at)endpoint(dot)com>
2005-01-12 21:06:32 from "Jonah H(dot) Harris" <jharris(at)tvi(dot)edu>
2005-01-12 21:17:57 from Jeff Davis <jdavis-pgsql(at)empires(dot)org>
2005-01-12 21:36:55 from "Jonah H(dot) Harris" <jharris(at)tvi(dot)edu>
2005-01-12 21:20:43 from Bruno Wolff III <bruno(at)wolff(dot)to>
2005-01-12 21:56:25 from Bruno Wolff III <bruno(at)wolff(dot)to>
2005-01-12 21:48:33 from "Jonah H(dot) Harris" <jharris(at)tvi(dot)edu>
2005-01-18 20:45:50 from Sailesh Krishnamurthy <sailesh(at)cs(dot)berkeley(dot)edu>
2005-01-18 22:10:48 from Jeff Davis <jdavis-pgsql(at)empires(dot)org>
2005-01-18 22:29:16 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-01-18 22:42:32 from Sailesh Krishnamurthy <sailesh(at)cs(dot)berkeley(dot)edu>
2005-01-18 23:01:01 from Jeff Davis <jdavis-pgsql(at)empires(dot)org>
2005-01-19 05:09:53 from Christopher Browne <cbbrowne(at)acm(dot)org>
2005-01-12 20:59:51 from Jeff Davis <jdavis-pgsql(at)empires(dot)org>
2005-01-13 10:12:49 from Christopher Kings-Lynne <chriskl(at)familyhealth(dot)com(dot)au>
2005-01-13 04:15:58 from Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
2005-01-13 04:54:52 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-01-13 04:57:56 from Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
2005-01-13 05:06:38 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-01-13 05:25:09 from Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
2005-01-13 05:39:56 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-01-13 14:04:46 from Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
2005-01-13 15:29:16 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-01-13 18:22:42 from "D'Arcy J(dot)M(dot) Cain" <darcy(at)druid(dot)net>
2005-01-13 19:20:36 from "Jonah H(dot) Harris" <jharris(at)tvi(dot)edu>
2005-01-16 19:49:45 from Manfred Koizar <mkoi-pg(at)aon(dot)at>
2005-01-16 20:11:37 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-01-16 20:22:11 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-01-17 00:53:01 from "Jim C(dot) Nasby" <decibel(at)decibel(dot)org>
2005-01-17 01:01:36 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-01-17 01:24:57 from Jochem van Dieten <jochemd(at)gmail(dot)com>
2005-01-17 01:28:07 from "Jim C(dot) Nasby" <decibel(at)decibel(dot)org>
2005-01-17 01:32:02 from "Jim C(dot) Nasby" <decibel(at)decibel(dot)org>
2005-01-17 01:34:58 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-01-22 21:19:16 from Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
2005-01-16 20:38:31 from Jochem van Dieten <jochemd(at)gmail(dot)com>
2005-01-22 20:06:33 from Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
2005-01-23 08:36:10 from Ron Mayer <rm_pg(at)cheapcomplexdevices(dot)com>
2005-01-23 21:36:18 from "Jim C(dot) Nasby" <decibel(at)decibel(dot)org>
2005-01-23 23:41:55 from Mark Kirkwood <markir(at)coretech(dot)co(dot)nz>
2005-01-24 15:28:09 from "Jonah H(dot) Harris" <jharris(at)tvi(dot)edu>
2005-01-25 07:33:57 from Manfred Koizar <mkoi-pg(at)aon(dot)at>
2005-01-25 12:03:28 from Christopher Browne <cbbrowne(at)acm(dot)org>
2005-01-12 18:36:52 from Reinhard Max <max(at)suse(dot)de>
2005-01-12 19:11:32 from Reinhard Max <max(at)suse(dot)de>
2005-01-12 19:59:42 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-01-12 20:10:16 from Reinhard Max <max(at)suse(dot)de>
2005-01-12 21:38:44 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2005-01-12 19:28:39 from Kurt Roeckx <Q(at)ping(dot)be>
2005-01-12 19:34:40 from Reinhard Max <max(at)suse(dot)de>
Lists:
pgsql-announce pgsql-hackers pgsql-patches
Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> My basic idea was to keep a status bit on each index entry telling it if
> a previous backend looked at the heap and determined it was valid.
Even if you could track the tuple's committed-good status reliably, that
isn't enough under MVCC. The tuple might be committed good, and seen
that way by some other backend that set the bit, and yet it's not supposed
to be visible to your older transaction. Or the reverse at tuple
deletion.
regards, tom lane
In response to
Responses
pgsql-announce by date
Next :From: Bruce MomjianDate: 2005-01-13 04:57:56Subject : Re: Much Ado About COUNT(*)Previous :From : Bruce MomjianDate : 2005-01-13 04:15:58Subject : Re: Much Ado About COUNT(*)
pgsql-hackers by date
Next :From: Bruce MomjianDate: 2005-01-13 04:57:56Subject : Re: Much Ado About COUNT(*)Previous :From : Bruce MomjianDate : 2005-01-13 04:15:58Subject : Re: Much Ado About COUNT(*)
pgsql-patches by date
Next :From: Bruce MomjianDate: 2005-01-13 04:57:56Subject : Re: Much Ado About COUNT(*)Previous :From : Bruce MomjianDate : 2005-01-13 04:15:58Subject : Re: Much Ado About COUNT(*)
