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

От: Andres Freund
Тема: [GENERAL] Questionaire: Common WAL write rates on busy servers.
Дата: ,
Msg-id: 20170425041743.ddabv2mwevcmtx5a@alap3.anarazel.de
(см: обсуждение, исходный текст)
Ответы: Re: [GENERAL] [PERFORM] Questionaire: Common WAL write rates on busy servers.  (Vladimir Borodin)
Re: [GENERAL] Questionaire: Common WAL write rates on busy servers.  (bricklen)
Re: [GENERAL] [PERFORM] Questionaire: Common WAL write rates on busy servers.  (Claudio Freire)
Re: [GENERAL] Questionaire: Common WAL write rates on busy servers.  (Jerry Sievers)
Re: [GENERAL] [PERFORM] Questionaire: Common WAL write rates on busy servers.  (Andres Freund)
Список: pgsql-general

Скрыть дерево обсуждения

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

Hi,

I've lately seen more and more installations where the generation of
write-ahead-log (WAL) is one of the primary bottlenecks.  I'm curious
whether that's primarily a "sampling error" of mine, or whether that's
indeed more common.

The primary reason I'm curious is that I'm pondering a few potential
optimizations, and would like to have some guidance which are more and
which are less important.

Questions (answer as many you can comfortably answer):
- How many MB/s, segments/s do you see on busier servers?
- What generates the bulk of WAL on your servers (9.5+ can use
  pg_xlogdump --stats to compute that)?
- Are you seeing WAL writes being a bottleneck?OA
- What kind of backup methods are you using and is the WAL volume a
  problem?
- What kind of replication are you using and is the WAL volume a
  problem?
- What are your settings for wal_compression, max_wal_size (9.5+) /
  checkpoint_segments (< 9.5), checkpoint_timeout and wal_buffers?
- Could you quickly describe your workload?

Feel free to add any information you think is pertinent ;)

Greetings,

Andres Freund



В списке pgsql-general по дате сообщения:

От: Vladimir Borodin
Дата:
Сообщение: Re: [GENERAL] [PERFORM] Questionaire: Common WAL write rates on busy servers.
От: Karri Niemelä
Дата:
Сообщение: [GENERAL] pg_test_fsync performance