Re: checkpoint segments

От: Alvaro Herrera
Тема: Re: checkpoint segments
Дата: ,
Msg-id: 20050516044053.GB9292@surnet.cl
(см: обсуждение, исходный текст)
Ответ на: Re: checkpoint segments  (Josh Berkus)
Ответы: Re: checkpoint segments  (Josh Berkus)
Список: pgsql-performance

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checkpoint segments  ("David Parker", )
 Re: checkpoint segments  (Josh Berkus, )
  Re: checkpoint segments  (Alvaro Herrera, )
   Re: checkpoint segments  (Josh Berkus, )
 Re: checkpoint segments  (Tom Lane, )
 Re: checkpoint segments  (Alvaro Herrera, )

On Sun, May 15, 2005 at 08:26:02PM -0700, Josh Berkus wrote:
> David,
>
> > I've seen these messages in the log before, and am aware of the need to
> > increase checkpoint_segments, but I wasn't aware that recycling a
> > transaction log could be that damaging to performance. There may have
> > been some local hiccup in this case, but I'm wondering if recycling is
> > known to be a big hit in general, and if I should strive to tune so that
> > it never happens (if that's possible)?
>
> Yes, and yes.   Simply allocating more checkpoint segments (which can eat a
> lot of disk space -- requirements are 16mb*(2 * segments +1) ) will prevent
> this problem.

Hmm?  I disagree -- it will only make things worse when the checkpoint
does occur.

--
Alvaro Herrera (<alvherre[a]surnet.cl>)
"Lo esencial es invisible para los ojos" (A. de Saint Exúpery)


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