Re: Aggressive autovacuuming ?

От: Kevin Grittner
Тема: Re: Aggressive autovacuuming ?
Дата: ,
Msg-id: 4C1F54A2020000250003270A@gw.wicourts.gov
(см: обсуждение, исходный текст)
Ответ на: Aggressive autovacuuming ?  (Jesper Krogh)
Список: pgsql-performance

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Aggressive autovacuuming ?  (Jesper Krogh, )
 Re: Aggressive autovacuuming ?  (Scott Marlowe, )
  Re: Aggressive autovacuuming ?  (Alvaro Herrera, )
  Re: Aggressive autovacuuming ?  (Robert Haas, )
   Re: Aggressive autovacuuming ?  (Scott Marlowe, )
    Re: Aggressive autovacuuming ?  (Robert Haas, )
 Re: Aggressive autovacuuming ?  ("Kevin Grittner", )

Jesper Krogh <> wrote:

> My thought was that if I tuned autovacuum to be "really
> aggressive" then I could get autovacuum to actually vacuum the
> tuples before they get evicted from the OS cache thus effectively
> "saving" the IO-overhead of vacuuming.

Interesting concept.  That might be a way to avoid the extra disk
I/O to set hint bits, and then some.  I haven't tried it, but I'm
going to make a note to take a look when (if???) I get some free
time.  If you give it a try, please post the results.  If you're I/O
bound (rather than CPU bound) and you choose *extremely* aggressive
settings, the multiple writes to pages *might* collapse in cache and
significantly reduce I/O.

I don't think I'd try it on a release prior to 8.4, however.  Nor
would I consider trying this in a production environment without a
good set of tests.

-Kevin


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