Re: [HACKERS] high shared buffer and swap

From: Matthew Wakeling
Subject: Re: [HACKERS] high shared buffer and swap
Date: ,
Msg-id: alpine.DEB.2.00.0905051220050.2341@aragorn.flymine.org
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In response to: Re: [HACKERS] high shared buffer and swap  (Laurent Laborde)
List: pgsql-performance

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high shared buffer and swap  (Laurent Laborde, )
 Re: high shared buffer and swap  (Greg Stark, )
  Re: [HACKERS] high shared buffer and swap  (Martijn van Oosterhout, )
 Re: high shared buffer and swap  (Scott Marlowe, )
 Re: [HACKERS] high shared buffer and swap  (PFC, )
  Re: [HACKERS] high shared buffer and swap  (Laurent Laborde, )
   Re: [HACKERS] high shared buffer and swap  (Matthew Wakeling, )

On Tue, 5 May 2009, Laurent Laborde wrote:
> I tried with swappinness set to 0 and ... it swaps !

While I wouldn't presume to try and teach you to suck eggs, once you set
swappiness to zero the system will take a while to settle down. The
swappiness setting will stop it swapping out, but if there is stuff out in
swap, then it won't force it to swap it in early. So the machine will
still thrash when it tries to access something that is out on swap. Easy
way to solve this is to swapoff the various swap partitions, which will
force it all into memory. You can swapon them again afterwards.

Matthew

--
Surely the value of C++ is zero, but C's value is now 1?
  -- map36, commenting on the "No, C++ isn't equal to D. 'C' is undeclared
  [...] C++ should really be called 1" response to "C++ -- shouldn't it
  be called D?"


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