From:
Bruce Momjian <bruce(at)momjian(dot)us>
To:
Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc:
Robert Haas <robertmhaas(at)gmail(dot)com>,Simon Riggs <simon(at)2ndquadrant(dot)com>,Jeff Janes <jeff(dot)janes(at)gmail(dot)com>,pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject:
Re: [PERFORM] Slow query: bitmap scan troubles
Date:
2013-01-15 19:46:39
Message-ID:
20130115194639.GG27934@momjian.us (view raw or flat )
Thread:
2012-12-04 15:06:48 from <postgresql(at)foo(dot)me(dot)uk>
2012-12-04 15:21:17 from <postgresql(at)foo(dot)me(dot)uk>
2012-12-04 15:27:57 from Claudio Freire <klaussfreire(at)gmail(dot)com>
2012-12-04 17:22:29 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2012-12-04 17:25:56 from Claudio Freire <klaussfreire(at)gmail(dot)com>
2012-12-04 17:35:32 from "Philip Scott" <pscott(at)foo(dot)me(dot)uk>
2012-12-04 17:47:29 from <postgresql(at)foo(dot)me(dot)uk>
2012-12-04 18:50:41 from Vitalii Tymchyshyn <tivv00(at)gmail(dot)com>
2012-12-04 18:55:17 from "Philip Scott" <pscott(at)foo(dot)me(dot)uk>
2012-12-04 18:56:04 from <postgresql(at)foo(dot)me(dot)uk>
2012-12-04 20:11:53 from Sergey Konoplev <gray(dot)ru(at)gmail(dot)com>
2012-12-06 12:56:26 from <postgresql(at)foo(dot)me(dot)uk>
2012-12-04 22:34:42 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2012-12-04 18:03:29 from <postgresql(at)foo(dot)me(dot)uk>
2012-12-04 18:31:50 from Claudio Freire <klaussfreire(at)gmail(dot)com>
2012-12-04 23:42:21 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2012-12-05 17:39:35 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2012-12-05 17:43:49 from Claudio Freire <klaussfreire(at)gmail(dot)com>
2012-12-06 17:27:48 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2012-12-06 20:05:09 from Claudio Freire <klaussfreire(at)gmail(dot)com>
2012-12-06 21:09:54 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2012-12-05 18:05:10 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2012-12-06 12:52:07 from <postgresql(at)foo(dot)me(dot)uk>
2012-12-18 06:00:16 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2013-01-05 22:18:16 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-01-06 16:29:17 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2013-01-06 18:18:03 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-01-06 18:22:33 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2013-01-06 18:19:10 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2013-01-06 18:58:40 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-01-06 19:47:48 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2013-01-06 23:03:05 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-01-06 23:17:23 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-01-07 00:03:04 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2013-01-07 17:35:51 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-01-07 18:03:37 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2013-01-07 18:27:38 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-01-07 18:48:12 from Claudio Freire <klaussfreire(at)gmail(dot)com>
2013-01-11 01:07:34 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-01-14 16:45:01 from Robert Haas <robertmhaas(at)gmail(dot)com>
2013-01-14 17:23:17 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-01-14 17:50:24 from Robert Haas <robertmhaas(at)gmail(dot)com>
2013-01-14 17:56:37 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2013-01-15 19:46:39 from Bruce Momjian <bruce(at)momjian(dot)us>
2013-01-15 20:11:02 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2012-12-19 01:05:05 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2012-12-19 14:40:54 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2012-12-06 14:10:29 from <postgresql(at)foo(dot)me(dot)uk>
2012-12-08 15:15:42 from Guillaume Lelarge <guillaume(at)lelarge(dot)info>
2012-12-10 09:52:42 from <postgresql(at)foo(dot)me(dot)uk>
2012-12-04 18:31:05 from "Philip Scott" <pscott(at)foo(dot)me(dot)uk>
2012-12-04 18:32:57 from Claudio Freire <klaussfreire(at)gmail(dot)com>
2012-12-04 18:54:29 from <postgresql(at)foo(dot)me(dot)uk>
Lists:
pgsql-hackers pgsql-performance
On Mon, Jan 14, 2013 at 12:56:37PM -0500, Tom Lane wrote:
> > The reported behavior was that the planner would prefer to
> > sequential-scan the table rather than use the index, even if
> > enable_seqscan=off. I'm not sure what the query looked like, but it
> > could have been something best implemented as a nested loop w/inner
> > index-scan.
>
> Remember also that "enable_seqscan=off" merely adds 1e10 to the
> estimated cost of seqscans. For sufficiently large tables this is not
> exactly a hard disable, just a thumb on the scales. But I don't know
> what your definition of "extremely large indexes" is.
Wow, do we need to bump up that value based on larger modern hardware?
--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ It's impossible for everything to be true. +
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