Re: Hash join on int takes 8..114 seconds

From: Tomas Vondra
Subject: Re: Hash join on int takes 8..114 seconds
Date: ,
Msg-id: 49271E95.5080200@fuzzy.cz
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In response to: Re: Hash join on int takes 8..114 seconds  ("Andrus")
List: pgsql-performance

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Hash join on int takes 8..114 seconds  ("Andrus", )
 Re: Hash join on int takes 8..114 seconds  (PFC, )
  Re: Hash join on int takes 8..114 seconds  ("Andrus", )
 Re: Hash join on int takes 8..114 seconds  (Richard Huxton, )
  Re: Hash join on int takes 8..114 seconds  ("Andrus", )
   Re: Hash join on int takes 8..114 seconds  (Richard Huxton, )
    Re: Hash join on int takes 8..114 seconds  ("Andrus", )
   Re: Hash join on int takes 8..114 seconds  (PFC, )
    Re: Hash join on int takes 8..114 seconds  ("Andrus", )
     Re: Hash join on int takes 8..114 seconds  (, )
      Re: Hash join on int takes 8..114 seconds  ("Andrus", )
       Re: Hash join on int takes 8..114 seconds  (PFC, )
       Re: Hash join on int takes 8..114 seconds  (Alan Hodgson, )
       Re: Hash join on int takes 8..114 seconds  (Tomas Vondra, )
     Re: Hash join on int takes 8..114 seconds  (Richard Huxton, )
      Re: Hash join on int takes 8..114 seconds  ("Andrus", )
       Re: Hash join on int takes 8..114 seconds  (PFC, )
        Re: Hash join on int takes 8..114 seconds  ("Andrus", )
         Re: Hash join on int takes 8..114 seconds  (Alvaro Herrera, )
          Re: Hash join on int takes 8..114 seconds  ("Andrus", )
           Re: Hash join on int takes 8..114 seconds  (Alvaro Herrera, )
            Re: Hash join on int takes 8..114 seconds  ("Andrus", )
             Re: Hash join on int takes 8..114 seconds  (Alvaro Herrera, )
           Re: Hash join on int takes 8..114 seconds  (Tomas Vondra, )
      Re: Hash join on int takes 8..114 seconds  ("Andrus", )
       Re: Hash join on int takes 8..114 seconds  (Scott Carey, )
     Re: Hash join on int takes 8..114 seconds  (PFC, )
      Re: Hash join on int takes 8..114 seconds  (Tom Lane, )
       Re: Hash join on int takes 8..114 seconds  (PFC, )
      Re: Hash join on int takes 8..114 seconds  ("Andrus", )
       Re: Hash join on int takes 8..114 seconds  (PFC, )
        Re: Hash join on int takes 8..114 seconds  ("Andrus", )
         Re: Hash join on int takes 8..114 seconds  (Tomas Vondra, )
          Re: Hash join on int takes 8..114 seconds  ("Andrus", )
           Re: Hash join on int takes 8..114 seconds  (Tomas Vondra, )
         Re: Hash join on int takes 8..114 seconds  (Scott Carey, )
          Re: Hash join on int takes 8..114 seconds  ("Andrus", )
           Re: Hash join on int takes 8..114 seconds  (Tomas Vondra, )
            Re: Hash join on int takes 8..114 seconds  ("Andrus", )
             Re: Hash join on int takes 8..114 seconds  (, )
              Re: Hash join on int takes 8..114 seconds  ("Andrus", )

> Thank you.
> My 8.1.4 postgresql.conf does not contain such option. So
> vacuum_cost_delay is off probably.
> Since doc does not recommend any value, I planned to use 2000
>
> Will value of 30 allow other clients to work when VACUUM FULL is running ?

No, as someone already noted the VACUUM FULL is blocking anyway (and
does not use this value at all).

> Uncommented relevant values in postgresql.conf file are:
>
> shared_buffers = 15000
> work_mem = 512

I'd consider increasing this value a little - 0.5 MB seems too low to me
(but not necessarily).

> maintenance_work_mem = 131072
> fsync = on
> effective_cache_size= 70000

Well, your server has 2GB of RAM and usually it's recommended to set
this value to about 60-70% of your RAM, so using 540MB (25%) seems quite
low. Anyway this is just a hint to PostgreSQL, it does not increase
memory consumption or so - it's just an estimate of how much data are
cached by kernel.

Anyway, I don't expect these values have significant effect in case of
the issue solved in this thread.

regards
Tomas


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