From:
"Jonah H(dot) Harris" <jharris(at)tvi(dot)edu>
To:
Simon Riggs <simon(at)2ndquadrant(dot)com>
Cc:
Rod Taylor <pg(at)rbt(dot)ca>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>,PostgreSQL Development <pgsql-hackers(at)postgresql(dot)org>
Subject:
Re: Much Ado About COUNT(*)
Date:
2005-01-12 21:58:14
Message-ID:
41E59D76.3090109@tvi.edu (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
Simon Riggs wrote:
>Jonah,
>
>People's objections are:
>- this shouldn't be the system default, so would need to be implemented
>as a non-default option on a b-tree index
>- its a lot of code and if you want it, you gotta do it
>
>Remember you'll need to
>- agree all changes via the list and accept that redesigns may be
>required, even at a late stage of coding
>- write visibility code into the index
>- write an additional node type to handle the new capability
>- microarchitecture performance testing so you know whether its really
>worthwhile, covering a range of cases
>- add code to the optimiser to so it can estimate the cost of using this
>and to know when to do this
>- add a column to the catalog to record whether an index has the
>visibility option
>- add code to the parser to invoke the option
>- update pg_dump so that it correctly dumps tables with that option
>- copy and adapt all of the existing tests for the new mechanism
>- document it
>
>If you really want to do all of that, I'm sure you'd get help, but
>mostly it will be you that has to drive the change through.
>
>There are some other benefits of that implementation:
>You'd be able to vacuum the index (only), allowing index access to
>remain reasonably constant, even as the table itself grew from dead
>rows.
>
>The index could then make sensible the reasonably common practice of
>using a covered index - i.e. putting additional columns into the index
>to satisfy the whole query just from the index.
>
>
>
Simon,
I am willing to take it on and I understand that the workload is mine.
As long as everyone gives me some suggestions, I'm good it being optional.
-Jonah
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