Re: PostgreSQL publishes first real benchmark

От: Stefan Kaltenbrunner
Тема: Re: PostgreSQL publishes first real benchmark
Дата: ,
Msg-id: 4695EF96.3060009@kaltenbrunner.cc
(см: обсуждение, исходный текст)
Ответ на: Re: PostgreSQL publishes first real benchmark  ("Jignesh K. Shah")
Ответы: Re: PostgreSQL publishes first real benchmark  (Gregory Stark)
Список: pgsql-performance

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PostgreSQL publishes first real benchmark  ("Jignesh K. Shah", )
 Re: PostgreSQL publishes first real benchmark  ("Jonah H. Harris", )
  Re: PostgreSQL publishes first real benchmark  ("Joshua D. Drake", )
   Re: PostgreSQL publishes first real benchmark  (Greg Smith, )
    Re: PostgreSQL publishes first real benchmark  ("Jonah H. Harris", )
     Re: PostgreSQL publishes first real benchmark  ("Joshua D. Drake", )
      Re: PostgreSQL publishes first real benchmark  ("Jonah H. Harris", )
 Re: PostgreSQL publishes first real benchmark  (Heikki Linnakangas, )
  Re: PostgreSQL publishes first real benchmark  ("Jignesh K. Shah", )
   Re: PostgreSQL publishes first real benchmark  ("Jim C. Nasby", )
 Re: PostgreSQL publishes first real benchmark  ("Steinar H. Gunderson", )
  Re: PostgreSQL publishes first real benchmark  ("Joshua D. Drake", )
   Re: PostgreSQL publishes first real benchmark  (Magnus Hagander, )
   Re: PostgreSQL publishes first real benchmark  (Vivek Khera, )
 Re: PostgreSQL publishes first real benchmark  ("Heiko W.Rupp", )
 Re: PostgreSQL publishes first real benchmark  (Philippe Amelant, )
  Re: PostgreSQL publishes first real benchmark  ("Jignesh K. Shah", )
  Re: PostgreSQL publishes first real benchmark  (André Gomes Lamas Otero, )
  Re: PostgreSQL publishes first real benchmark  (Philippe Amelant, )
 Re: PostgreSQL publishes first real benchmark  (Heikki Linnakangas, )
  Re: PostgreSQL publishes first real benchmark  ("Jignesh K. Shah", )
   Re: PostgreSQL publishes first real benchmark  (Tom Lane, )
    Re: PostgreSQL publishes first real benchmark  ("Jignesh K. Shah", )
     Re: PostgreSQL publishes first real benchmark  (Stefan Kaltenbrunner, )
      Re: PostgreSQL publishes first real benchmark  (Gregory Stark, )
       Re: PostgreSQL publishes first real benchmark  (Greg Smith, )
        Re: PostgreSQL publishes first real benchmark  (Ray Stell, )

Jignesh K. Shah wrote:
> Can you list others that seemed out of place?

well to me the ones that look most questionable are:

work_mem=100MB - so this benchmark is really low concurrency(which does
not fit with max_connections=1000) and with trivial queries ?

enable_seqscan = off - why ?

effective_cache_size = 40GB - on a box with 16GB this seems wrong
especially since there are some indications out there that suggest that
while overestimating effective_cache_size was not a problem in versions
<8.2 it might not be so in 8.2 and up

wal_buffers = 2300 - there have been some numbers reported that going
over the default of 8 helps but it is generally considered that going
beyond 500 or maybe 1000 does not help at all ...


and one more is that you claim you used "-fast -O4 -xtarget=ultraT1"
which is something we explicitly advise against in our own
FAQ(http://www.postgresql.org/docs/faqs.FAQ_Solaris.html):

"Do not use any flags that modify behavior of floating point operations
and errno processing (e.g.,-fast).  These flags could raise some
nonstandard PostgreSQL behavior for example in the date/time computing."



Stefan


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