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Re: [kris@obsecurity.org: Progress on scaling of FreeBSD on 8 CPU systems]

From: Tom Lane
Subject: Re: [kris@obsecurity.org: Progress on scaling of FreeBSD on 8 CPU systems]
Date: ,
Msg-id: 22074.1173127131@sss.pgh.pa.us
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In response to: Re: [kris@obsecurity.org: Progress on scaling of FreeBSD on 8 CPU systems]  (Stefan Kaltenbrunner)
Responses: Re: [kris@obsecurity.org: Progress on scaling of FreeBSD on 8 CPU systems]  (Arjen van der Meijden)
Re: [kris@obsecurity.org: Progress on scaling of FreeBSD on 8 CPU systems]  (Stefan Kaltenbrunner)
List: pgsql-performance

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[kris@obsecurity.org: Progress on scaling of FreeBSD on 8 CPU systems]  ("Jim C. Nasby", )
 Re: [kris@obsecurity.org: Progress on scaling of FreeBSD on 8 CPU systems]  (Alvaro Herrera, )
  Re: [kris@obsecurity.org: Progress on scaling of FreeBSD on 8 CPU systems]  (Arjen van der Meijden, )
   Re: [kris@obsecurity.org: Progress on scaling of FreeBSD on 8 CPU systems]  (Arjen van der Meijden, )
    Re: [kris@obsecurity.org: Progress on scaling of FreeBSD on 8 CPU systems]  (Stefan Kaltenbrunner, )
     Re: [kris@obsecurity.org: Progress on scaling of FreeBSD on 8 CPU systems]  (Arjen van der Meijden, )
      Re: [kris@obsecurity.org: Progress on scaling of FreeBSD on 8 CPU systems]  (Stefan Kaltenbrunner, )
       Re: [kris@obsecurity.org: Progress on scaling of FreeBSD on 8 CPU systems]  (Tom Lane, )
        Re: [kris@obsecurity.org: Progress on scaling of FreeBSD on 8 CPU systems]  (Arjen van der Meijden, )
        Re: [kris@obsecurity.org: Progress on scaling of FreeBSD on 8 CPU systems]  (Stefan Kaltenbrunner, )
    Re: [kris@obsecurity.org: Progress on scaling of FreeBSD on 8 CPU systems]  (Richard Huxton, )
  Re: [kris@obsecurity.org: Progress on scaling of FreeBSD on 8 CPU systems]  (Scott Marlowe, ) 
Stefan Kaltenbrunner <> writes:
> Arjen van der Meijden wrote:
>> Stefan Kaltenbrunner wrote:
>>> ouch - do I read that right that even after tom's fixes for the
>>> "regressions" in 8.2.0 we are still 30% slower then the -HEAD checkout
>>> from the middle of the 8.2 development cycle ?
>>
>> Yes, and although I tested about 17 different cvs-checkouts, Tom and I
>> weren't really able to figure out where "it" happened. So its a bit of a
>> mystery why the performance is so much worse.

> double ouch - losing that much in performance without an idea WHY it
> happened is really unfortunate :-(

Keep in mind that Arjen's test exercises some rather narrow scenarios;
IIRC its performance is mostly determined by some complicated
bitmap-indexscan cases.  So that "30% slower" bit certainly doesn't
represent an across-the-board figure.  As best I can tell, the decisions
the planner happened to be making in late June were peculiarly nicely
suited to his test, but not so much for other cases.

            regards, tom lane

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