Re: Caching by Postgres

From: Tom Lane
Subject: Re: Caching by Postgres
Date: ,
Msg-id: 21392.1124860042@sss.pgh.pa.us
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In response to: Re: Caching by Postgres  (Gavin Sherry)
Responses: Re: Caching by Postgres  (Gavin Sherry)
List: pgsql-performance

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Caching by Postgres  (gokulnathbabu manoharan, )
 Re: Caching by Postgres  (John A Meinel, )
  Re: Caching by Postgres  (Josh Berkus, )
 Re: Caching by Postgres  (Bruno Wolff III, )
 Re: Caching by Postgres  (Frank Wiles, )
  Re: Caching by Postgres  (Donald Courtney, )
   Re: Caching by Postgres  (Tom Lane, )
   Re: Caching by Postgres  (Josh Berkus, )
    Re: Caching by Postgres  (Michael Stone, )
   Re: Caching by Postgres  (, )
   Re: Caching by Postgres  (William Yu, )
    Re: Caching by Postgres  (PFC, )
     Re: Caching by Postgres  (Josh Berkus, )
      Re: Caching by Postgres  (PFC, )
     Re: Caching by Postgres  (Gavin Sherry, )
      Re: Caching by Postgres  (Tom Lane, )
       Re: Caching by Postgres  (Gavin Sherry, )
    Re: Caching by Postgres  (Donald Courtney, )
     Re: Caching by Postgres  (Stephen Frost, )
     Re: Caching by Postgres  (, )
      Re: Caching by Postgres  (Alan Stange, )
       Re: Caching by Postgres  (, )
        Re: Caching by Postgres  (Alan Stange, )
         Re: Caching by Postgres  (, )
        Re: Caching by Postgres  (Michael Stone, )
         Re: Caching by Postgres  (, )
       Re: Caching by Postgres  (PFC, )
      Re: Caching by Postgres  (Thomas Ganss, )
     Re: Caching by Postgres  (William Yu, )
 Re: Caching by Postgres  (Chris Browne, )
 Re: Caching by Postgres  (Chris Browne, )

Gavin Sherry <> writes:
> A filesystem could, in theory, help us by providing an API which allows us
> to tell the file system either: the way we'd like it to read ahead, the
> fact that we don't want it to read ahead or the way we'd like it to cache
> (or not cache) data. The thing is, most OSes provide interfaces to do this
> already and we make only little use of them (I'm think of
> madv_sequential(), madv_random(), POSIX fadvise(), the various flags to
> open() which AIX, HPUX, Solaris provide).

Yeah ... the main reason we've not spent too much time on that sort of
stuff is that *it's not portable*.  And with all due respect to Hans,
special tweaks for one filesystem are even less interesting than special
tweaks for one OS.

            regards, tom lane


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