Re: [PERFORM] Questionaire: Common WAL write rates on busy servers.

От: Andres Freund
Тема: Re: [PERFORM] Questionaire: Common WAL write rates on busy servers.
Дата: ,
Msg-id: 20170427233433.eg5vwlvbqyc2nruh@alap3.anarazel.de
(см: обсуждение, исходный текст)
Ответ на: Re: [PERFORM] Questionaire: Common WAL write rates on busy servers.  (Tomas Vondra)
Ответы: Re: [PERFORM] Questionaire: Common WAL write rates on busy servers.  (Tomas Vondra)
Список: pgsql-performance

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[PERFORM] Questionaire: Common WAL write rates on busy servers.  (Andres Freund, )
 Re: [PERFORM] Questionaire: Common WAL write rates on busy servers.  (Vladimir Borodin, )
 Re: [PERFORM] [GENERAL] Questionaire: Common WAL write rates on busy servers.  (bricklen, )
 Re: [PERFORM] Questionaire: Common WAL write rates on busy servers.  (Claudio Freire, )
 Re: [PERFORM] Questionaire: Common WAL write rates on busy servers.  (Andres Freund, )
  Re: [PERFORM] Questionaire: Common WAL write rates on busy servers.  ("Joshua D. Drake", )
   Re: [PERFORM] Questionaire: Common WAL write rates on busy servers.  (Andres Freund, )
    Re: [PERFORM] Questionaire: Common WAL write rates on busy servers.  ("Joshua D. Drake", )
     Re: [PERFORM] Questionaire: Common WAL write rates on busy servers.  (Andres Freund, )
      Re: [PERFORM] Questionaire: Common WAL write rates on busy servers.  (Tomas Vondra, )
       Re: [PERFORM] Questionaire: Common WAL write rates on busy servers.  (Andres Freund, )
        Re: [PERFORM] Questionaire: Common WAL write rates on busy servers.  (Tomas Vondra, )
    Re: [PERFORM] Questionaire: Common WAL write rates on busy servers.  (Tomas Vondra, )
 Re: [PERFORM] Questionaire: Common WAL write rates on busy servers.  (Tomas Vondra, )

On 2017-04-28 01:29:14 +0200, Tomas Vondra wrote:
> I can confirm this observation. I bought the Intel 750 NVMe SSD last year,
> the device has 1GB DDR3 cache on it (power-loss protected), can do ~1GB/s of
> sustained O_DIRECT sequential writes. But when running pgbench, I can't push
> more than ~300MB/s of WAL to it, no matter what I do because of
> WALWriteLock.

Hm, interesting.  Even if you up wal_buffers to 128MB, use
synchronous_commit = off, and play with wal_writer_delay/flush_after?

- Andres



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От: Andres Freund
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Сообщение: Re: [PERFORM] Questionaire: Common WAL write rates on busy servers.
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Сообщение: Re: [PERFORM] Questionaire: Common WAL write rates on busy servers.