Re: configure shmmax on MAC OS X - Mailing list pgsql-performance

From Tom Lane
Subject Re: configure shmmax on MAC OS X
Date
Msg-id 25965.1081886115@sss.pgh.pa.us
Whole thread Raw
In response to configure shmmax on MAC OS X  (Qing Zhao <qzhao@quotefx.net>)
Responses Re: configure shmmax on MAC OS X  (Qing Zhao <qzhao@quotefx.net>)
Re: configure shmmax on MAC OS X  ("Joshua D. Drake" <jd@commandprompt.com>)
List pgsql-performance
Qing Zhao <qzhao@quotefx.net> writes:
> My suspision is that the change i made in /etc/rc does not take
> effect.Is there a way to check it?

sysctl has an option to show the values currently in effect.

I believe that /etc/rc is the correct place to set shmmax on OSX 10.3 or
later ... but we have seen prior reports of people having trouble
getting the setting to "take".  There may be some other constraint
involved.

> sysctl -w kern.sysv.shmmax=4294967296 // byte

Hmm, does sysctl work for values that exceed the range of int?

There's no particularly good reason to try to set shmmax as high as you
are trying anyhow; you really don't need more than a couple hundred meg
in Postgres shared memory.  It's better to leave the kernel to manage
the bulk of your RAM.

            regards, tom lane

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