Re: strange performance regression between 7.4 and 8.1

От: Florian Weimer
Тема: Re: strange performance regression between 7.4 and 8.1
Дата: ,
Msg-id: 82slco6n9t.fsf@mid.bfk.de
(см: обсуждение, исходный текст)
Ответ на: strange performance regression between 7.4 and 8.1  ("Alex Deucher")
Ответы: Re: strange performance regression between 7.4 and 8.1  (Carlos Moreno)
Re: strange performance regression between 7.4 and 8.1  ("Alex Deucher")
Re: strange performance regression between 7.4 and 8.1  (Alvaro Herrera)
Список: pgsql-performance

Скрыть дерево обсуждения

strange performance regression between 7.4 and 8.1  ("Alex Deucher", )
 Re: strange performance regression between 7.4 and 8.1  ("Joshua D. Drake", )
  Re: strange performance regression between 7.4 and 8.1  (Jeff Frost, )
   Re: strange performance regression between 7.4 and 8.1  ("Alex Deucher", )
    Re: strange performance regression between 7.4 and 8.1  (Jeff Frost, )
   Re: strange performance regression between 7.4 and 8.1  ("Alex Deucher", )
    Re: strange performance regression between 7.4 and 8.1  (Jeff Frost, )
     Re: strange performance regression between 7.4 and 8.1  ("Alex Deucher", )
      Re: strange performance regression between 7.4 and 8.1  (Tom Lane, )
       Re: strange performance regression between 7.4 and 8.1  ("Alex Deucher", )
  Re: strange performance regression between 7.4 and 8.1  ("Alex Deucher", )
   Re: strange performance regression between 7.4 and 8.1  (Jeff Frost, )
    Re: strange performance regression between 7.4 and 8.1  ("Alex Deucher", )
     Re: strange performance regression between 7.4 and 8.1  (Jeff Frost, )
      Re: strange performance regression between 7.4 and 8.1  ("Alex Deucher", )
       Re: strange performance regression between 7.4 and 8.1  (Jeff Frost, )
        Re: strange performance regression between 7.4 and 8.1  ("Alex Deucher", )
         Re: strange performance regression between 7.4 and 8.1  ("Joshua D. Drake", )
          Re: strange performance regression between 7.4 and 8.1  ("Alex Deucher", )
           Re: strange performance regression between 7.4 and 8.1  ("Joshua D. Drake", )
            Re: strange performance regression between 7.4 and 8.1  ("Alex Deucher", )
         Re: strange performance regression between 7.4 and 8.1  (Jeff Frost, )
          Re: strange performance regression between 7.4 and 8.1  ("Alex Deucher", )
 Re: strange performance regression between 7.4 and 8.1  (Ron, )
 Re: strange performance regression between 7.4 and 8.1  (Florian Weimer, )
  Re: strange performance regression between 7.4 and 8.1  (Carlos Moreno, )
   Re: strange performance regression between 7.4 and 8.1  (Ron, )
  Re: strange performance regression between 7.4 and 8.1  ("Alex Deucher", )
  Re: strange performance regression between 7.4 and 8.1  (Alvaro Herrera, )
 Re: strange performance regression between 7.4 and 8.1  (Ron, )
  Re: strange performance regression between 7.4 and 8.1  ("Alex Deucher", )
   Re: strange performance regression between 7.4 and 8.1  (Scott Marlowe, )
 Re: strange performance regression between 7.4 and 8.1  (Ron, )
  Re: strange performance regression between 7.4 and 8.1  ("Alex Deucher", )
 Re: strange performance regression between 7.4 and 8.1  (Anton Rommerskirchen, )
 Re: strange performance regression between 7.4 and 8.1  (Ron, )
  Re: strange performance regression between 7.4 and 8.1  ("Alex Deucher", )
   Re: strange performance regression between 7.4 and 8.1  (Guido Neitzer, )
    Re: strange performance regression between 7.4 and 8.1  (Jeff Frost, )
     Re: strange performance regression between 7.4 and 8.1  ("Alex Deucher", )

* Alex Deucher:

> I have noticed a strange performance regression and I'm at a loss as
> to what's happening.  We have a fairly large database (~16 GB).

Sorry for asking, but is this a typo?  Do you mean 16 *TB* instead of
16 *GB*?

If it's really 16 GB, you should check if it's cheaper to buy more RAM
than to fiddle with the existing infrastructure.

> however the table structure is almost identical (UTF8 on the new one
> vs. C on the old).

Locale settings make a huge difference for sorting and LIKE queries.
We usually use the C locale and SQL_ASCII encoding, mostly for
performance reasons.  (Proper UTF-8 can be enforced through
constraints if necessary.)

--
Florian Weimer                <>
BFK edv-consulting GmbH       http://www.bfk.de/
Kriegsstraße 100              tel: +49-721-96201-1
D-76133 Karlsruhe             fax: +49-721-96201-99


В списке pgsql-performance по дате сообщения:

От: Carlos Moreno
Дата:
Сообщение: Re: strange performance regression between 7.4 and 8.1
От: Alvaro Herrera
Дата:
Сообщение: Re: [kris@obsecurity.org: Progress on scaling of FreeBSD on 8 CPU systems]