Re: Pre-allocation of shared memory ...

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От Bruce Momjian
Тема Re: Pre-allocation of shared memory ...
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Msg-id 200306121646.h5CGkdQ10035@candle.pha.pa.us
обсуждение исходный текст
Ответ на Re: Pre-allocation of shared memory ...  ("Andrew Dunstan" <andrew@dunslane.net>)
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Well, let's see what feedback we get.

---------------------------------------------------------------------------

Andrew Dunstan wrote:
> 
> A couple of points:
> 
> . It is probably a good idea to put do this via /etc/sysctl.conf, which will
> be called earlyish by init scripts (on RH9 it is in the network startup
> file, for some reason).
> 
> . The setting is not available on all kernel versions AFAIK. The admin needs
> to check the docs. I have no idea when this went into the kernel, and no
> time to spend finding out. Even if we knew, it might have gone into vendor
> kernels at other odd times  - there are often times when the vendors are in
> advance of the officially released kernels.
> 
> Andrew
> 
> 
> Bruce wrote:
> >
> > OK, new text is:
> >
> >       <para>
> >        Linux has poor default memory overcommit behavior.  Rather than
> >        failing if it can not reserve enough memory, it returns success,
> >        but later fails when the memory can't be mapped and terminates
> >        the application with <literal>kill -9</>.  To prevent
> >        unpredictable process termination, use:
> > <programlisting>
> > sysctl -w vm.overcommit_memory=3
> > </programlisting>
> >        Note, you will need enough swap space to cover all your memory
> >        needs.
> >       </para>
> >      </listitem>
> >     </varlistentry>
> >
> > ---------------------------------------------------------------------------
> >
> > Tom Lane wrote:
> >> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> >> > OK, doc patch attached and applied.  Improvements?
> >>
> >> I think it would be worth spending another sentence to tell people
> >> exactly what the symptom looks like, ie, backends dying with signal 9.
> >>
> >>             regards, tom lane
> >>
> >
> > --
> >  Bruce Momjian                        |  http://candle.pha.pa.us
> >  pgman@candle.pha.pa.us               |  (610) 359-1001
> >  +  If your life is a hard drive,     |  13 Roberts Road
> >  +  Christ can be your backup.        |  Newtown Square, Pennsylvania
> >  19073
> >
> > ---------------------------(end of
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> >    (send "unregister YourEmailAddressHere" to majordomo@postgresql.org)
> 
> 
> 
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster
> 

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
359-1001+  If your life is a hard drive,     |  13 Roberts Road +  Christ can be your backup.        |  Newtown Square,
Pennsylvania19073
 


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