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Re: Proposal of tunable fix for scalability of 8.4

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From:	Alvaro Herrera
Subject:	Re: Proposal of tunable fix for scalability of 8.4
Date:	March 12, 2009 , 19:11:39
Msg-id:	20090312191020.GB29971@alvh.no-ip.org (view: Whole thread, Raw)
In response to:	Re: Proposal of tunable fix for scalability of 8.4 (Tom Lane)
Responses:	Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah")
List:	pgsql-performance

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Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 11 March 2009, 21:48:21 )
Re: Proposal of tunable fix for scalability of 8.4 ("Kevin Grittner", 11 March 2009, 22:27:24 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 12 March 2009, 00:55:52 )
Re: Proposal of tunable fix for scalability of 8.4 ("Kevin Grittner", 12 March 2009, 14:08:02 )
Re: Proposal of tunable fix for scalability of 8.4 (Tom Lane, 12 March 2009, 01:32:43 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 12 March 2009, 02:20:45 )
Re: Proposal of tunable fix for scalability of 8.4 (Simon Riggs, 17 March 2009, 09:17:48 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 17 March 2009, 13:18:23 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 17 March 2009, 21:46:04 )
Re: Proposal of tunable fix for scalability of 8.4 (Simon Riggs, 17 March 2009, 22:59:45 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 18 March 2009, 00:14:04 )
Re: Proposal of tunable fix for scalability of 8.4 (Simon Riggs, 18 March 2009, 00:43:32 )
Re: Proposal of tunable fix for scalability of 8.4 (Gregory Stark, 18 March 2009, 11:36:30 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 18 March 2009, 21:16:10 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 18 March 2009, 22:01:54 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 12 March 2009, 02:02:07 )
Re: Proposal of tunable fix for scalability of 8.4 (Tom Lane, 12 March 2009, 02:51:08 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 12 March 2009, 03:48:46 )
Re: Proposal of tunable fix for scalability of 8.4 (decibel, 14 March 2009, 16:49:53 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 15 March 2009, 20:40:10 )
Re: Proposal of tunable fix for scalability of 8.4 (Josh Berkus, 29 March 2009, 21:33:53 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 12 March 2009, 17:48:26 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 12 March 2009, 18:41:47 )
Re: Proposal of tunable fix for scalability of 8.4 ("Kevin Grittner", 12 March 2009, 19:26:20 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 12 March 2009, 22:57:21 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 13 March 2009, 12:38:47 )
Re: Proposal of tunable fix for scalability of 8.4 (Gregory Stark, 13 March 2009, 13:05:50 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 13 March 2009, 13:37:40 )
Re: Proposal of tunable fix for scalability of 8.4 (Gregory Stark, 13 March 2009, 13:54:19 )
Re: Proposal of tunable fix for scalability of 8.4 (decibel, 14 March 2009, 16:50:21 )
Re: Proposal of tunable fix for scalability of 8.4 (Gregory Stark, 13 March 2009, 13:28:50 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 13 March 2009, 14:56:56 )
Re: Proposal of tunable fix for scalability of 8.4 ("Kevin Grittner", 13 March 2009, 15:56:09 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 13 March 2009, 16:54:14 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 13 March 2009, 17:21:39 )
Re: Proposal of tunable fix for scalability of 8.4 ("Kevin Grittner", 13 March 2009, 16:18:29 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 13 March 2009, 16:42:48 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 13 March 2009, 17:30:14 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 13 March 2009, 17:48:59 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 13 March 2009, 18:48:43 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 13 March 2009, 20:02:56 )
Re: Proposal of tunable fix for scalability of 8.4 (decibel, 14 March 2009, 16:50:33 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 15 March 2009, 20:42:52 )
Re: Proposal of tunable fix for scalability of 8.4 (Gregory Stark, 16 March 2009, 15:08:38 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 16 March 2009, 19:43:28 )
Re: Proposal of tunable fix for scalability of 8.4 (Greg Smith, 13 March 2009, 04:23:45 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 12 March 2009, 15:01:24 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 12 March 2009, 17:09:38 )
Re: Proposal of tunable fix for scalability of 8.4 (Greg Smith, 12 March 2009, 20:35:36 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 12 March 2009, 22:16:19 )
Re: Proposal of tunable fix for scalability of 8.4 (Robert Haas, 13 March 2009, 01:30:08 )
Re: Proposal of tunable fix for scalability of 8.4 (Tom Lane, 13 March 2009, 17:16:53 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 13 March 2009, 17:34:42 )
Re: Proposal of tunable fix for scalability of 8.4 ("Kevin Grittner", 13 March 2009, 18:02:51 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 13 March 2009, 18:39:19 )
Re: Proposal of tunable fix for scalability of 8.4 (, 14 March 2009, 04:29:47 )
Re: Proposal of tunable fix for scalability of 8.4 ("Kevin Grittner", 16 March 2009, 15:48:45 )
Re: Proposal of tunable fix for scalability of 8.4 ("Kevin Grittner", 16 March 2009, 16:53:55 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 16 March 2009, 18:45:02 )
Re: Proposal of tunable fix for scalability of 8.4 (Heikki Linnakangas, 14 March 2009, 08:24:09 )
Re: Proposal of tunable fix for scalability of 8.4 (Tom Lane, 14 March 2009, 16:10:18 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 15 March 2009, 19:25:29 )
Re: Proposal of tunable fix for scalability of 8.4 (Simon Riggs, 18 March 2009, 07:48:52 )
Re: Proposal of tunable fix for scalability of 8.4 (Matthew Wakeling, 16 March 2009, 16:26:38 )
Re: Proposal of tunable fix for scalability of 8.4 (Simon Riggs, 18 March 2009, 07:54:54 )
Re: Proposal of tunable fix for scalability of 8.4 (Matthew Wakeling, 18 March 2009, 11:46:03 )
Re: Proposal of tunable fix for scalability of 8.4 (Simon Riggs, 18 March 2009, 12:07:00 )
Re: Proposal of tunable fix for scalability of 8.4 (Matthew Wakeling, 18 March 2009, 12:33:58 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 18 March 2009, 13:42:10 )
Re: Proposal of tunable fix for scalability of 8.4 (Matthew Wakeling, 18 March 2009, 13:49:12 )
Re: Proposal of tunable fix for scalability of 8.4 (Simon Riggs, 18 March 2009, 23:07:41 )
Re: Proposal of tunable fix for scalability of 8.4 (Tom Lane, 18 March 2009, 20:26:55 )
Re: Proposal of tunable fix for scalability of 8.4 (Simon Riggs, 18 March 2009, 23:07:07 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 20 March 2009, 06:31:10 )
Re: Proposal of tunable fix for scalability of 8.4 (Matthew Wakeling, 20 March 2009, 15:28:53 )
Re: Proposal of tunable fix for scalability of 8.4 (Tom Lane, 20 March 2009, 15:55:55 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 20 March 2009, 18:54:08 )
Re: Proposal of tunable fix for scalability of 8.4 (Simon Riggs, 21 March 2009, 08:50:39 )
Re: Proposal of tunable fix for scalability of 8.4 (Heikki Linnakangas, 18 March 2009, 11:49:11 )
Re: Proposal of tunable fix for scalability of 8.4 (Matthew Wakeling, 18 March 2009, 11:49:39 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 18 March 2009, 17:43:26 )
Re: Proposal of tunable fix for scalability of 8.4 (Robert Haas, 18 March 2009, 21:25:15 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 18 March 2009, 22:15:45 )
Re: Proposal of tunable fix for scalability of 8.4 (Robert Haas, 19 March 2009, 20:49:54 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 19 March 2009, 21:43:33 )
Re: Proposal of tunable fix for scalability of 8.4 (Robert Haas, 20 March 2009, 03:45:26 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 20 March 2009, 06:05:46 )
Re: Proposal of tunable fix for scalability of 8.4 (Alvaro Herrera, 20 March 2009, 15:46:16 )
Re: Proposal of tunable fix for scalability of 8.4 (Alvaro Herrera, 20 March 2009, 21:58:38 )
Re: Proposal of tunable fix for scalability of 8.4 (Alvaro Herrera, 20 March 2009, 22:05:27 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 20 March 2009, 23:39:21 )
Re: Proposal of tunable fix for scalability of 8.4 (Robert Haas, 21 March 2009, 00:45:33 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 21 March 2009, 23:02:54 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 19 March 2009, 23:12:34 )
Re: Proposal of tunable fix for scalability of 8.4 (Bruce Momjian, 19 March 2009, 17:38:04 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 19 March 2009, 20:58:50 )
Re: Proposal of tunable fix for scalability of 8.4 (Bruce Momjian, 19 March 2009, 23:27:26 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 19 March 2009, 20:57:25 )
Re: Proposal of tunable fix for scalability of 8.4 (Greg Smith, 13 March 2009, 03:00:54 )
8.4 Performance improvements: was Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 13 March 2009, 12:44:53 )
Re: 8.4 Performance improvements: was Re: Proposal of tunable fix for scalability of 8.4 (Gregory Stark, 13 March 2009, 13:43:16 )
Re: 8.4 Performance improvements: was Re: Proposal of tunable fix for scalability of 8.4 (Gregory Stark, 13 March 2009, 13:57:19 )
Re: 8.4 Performance improvements: was Re: Proposal of tunable fix for scalability of 8.4 (Alan Stange, 13 March 2009, 15:37:53 )
Re: 8.4 Performance improvements: was Re: Proposal of tunable fix for scalability of 8.4 (Tom Lane, 13 March 2009, 17:23:53 )
Re: 8.4 Performance improvements: was Re: Proposal of tunable fix for scalability of 8.4 (Gregory Stark, 14 March 2009, 01:59:00 )
Re: 8.4 Performance improvements: was Re: Proposal of tunable fix for scalability of 8.4 (Tom Lane, 14 March 2009, 02:06:26 )
Re: 8.4 Performance improvements: was Re: Proposal of tunable fix for scalability of 8.4 (Robert Haas, 14 March 2009, 02:37:41 )
Re: 8.4 Performance improvements: was Re: Proposal of tunable fix for scalability of 8.4 (Gregory Stark, 14 March 2009, 04:03:01 )
Re: 8.4 Performance improvements: was Re: Proposal of tunable fix for scalability of 8.4 (Tom Lane, 14 March 2009, 16:02:37 )
Re: 8.4 Performance improvements: was Re: Proposal of tunable fix for scalability of 8.4 (Bruce Momjian, 02 April 2009, 23:09:01 )
Re: 8.4 Performance improvements: was Re: Proposal of tunable fix for scalability of 8.4 (Bruce Momjian, 07 April 2009, 22:49:39 )
Re: 8.4 Performance improvements: was Re: Proposal of tunable fix for scalability of 8.4 (Greg Smith, 13 March 2009, 17:15:48 )
Re: Proposal of tunable fix for scalability of 8.4 ("Kevin Grittner", 12 March 2009, 15:13:46 )
Re: Proposal of tunable fix for scalability of 8.4 (Grzegorz Jaśkiewicz, 12 March 2009, 15:31:31 )
Re: Proposal of tunable fix for scalability of 8.4 ("Kevin Grittner", 12 March 2009, 15:44:59 )
Re: Proposal of tunable fix for scalability of 8.4 (Ron, 12 March 2009, 18:33:00 )
Re: Proposal of tunable fix for scalability of 8.4 (Gregory Stark, 12 March 2009, 17:10:09 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 12 March 2009, 18:08:56 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 12 March 2009, 17:39:24 )
Re: Proposal of tunable fix for scalability of 8.4 (Tom Lane, 12 March 2009, 18:28:19 )
Re: Proposal of tunable fix for scalability of 8.4 (Alvaro Herrera, 12 March 2009, 19:11:39 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 12 March 2009, 19:26:43 )
Re: Proposal of tunable fix for scalability of 8.4 (decibel, 14 March 2009, 16:50:12 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 12 March 2009, 21:46:16 )
Re: Proposal of tunable fix for scalability of 8.4 (Tom Lane, 12 March 2009, 17:53:28 )
Re: Proposal of tunable fix for scalability of 8.4 (Scott Carey, 12 March 2009, 18:09:50 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 12 March 2009, 17:53:33 )
Re: Proposal of tunable fix for scalability of 8.4 (Simon Riggs, 14 March 2009, 13:30:27 )
Re: Proposal of tunable fix for scalability of 8.4 ("Jignesh K. Shah", 15 March 2009, 20:37:02 )

Tom Lane wrote:
> Scott Carey <> writes:
> > They are not meaningless.  It is certainly more to understand, but the test is entirely valid without that.  In a
CPUbound / RAM bound case, as concurrency increases you look for the throughput trend, the %CPU use trend and the
contextswitch rate trend.  More information would be useful but the test is validated by the evidence that it is held
upby lock contention. 
>
> Er ... *what* evidence?  There might be evidence somewhere that proves
> that, but Jignesh hasn't shown it.  The available data suggests that the
> first-order performance limiter in this test is something else.
> Otherwise it should be possible to max out the performance with a lot
> less than 1000 active backends.

With 200ms of think times as Jignesh just said, 1000 users does not
equate 1000 active backends.  (It's probably closer to 100 backends,
given an avg. response time of ~20ms)

Something that might be useful for him to report is the avg number of
active backends for each data point ...

--
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support

pgsql-performance by date:

From: Scott Carey
Date: 12 March 2009, 16:57:21
Subject: Re: Proposal of tunable fix for scalability of 8.4

From: Robert Haas
Date: 12 March 2009, 19:30:08
Subject: Re: Proposal of tunable fix for scalability of 8.4