Re: SHMMAX value - Mailing list pgsql-general

From Peter Eisentraut
Subject Re: SHMMAX value
Date
Msg-id Pine.LNX.4.30.0106271935560.729-100000@peter.localdomain
Whole thread Raw
In response to SHMMAX value  ("Thalis A. Kalfigopoulos" <thalis@cs.pitt.edu>)
List pgsql-general
Thalis A. Kalfigopoulos writes:

> This was asked repeatedly the past 2 weeks. With regard to "what is a
> sane value for shmmax in the kernel?" Oracle's recommendation is to go
> for 0.5*physical_memory. So I gues that 0.25*physical_memory for Pg
> should be fine.

The only reason that I can see not to set SHMMAX to infinity is that some
joe user could lock up all your available memory.  This problem is present
for any value, but depending on how your kernel handles shared memory when
physical memory is tight it might get worse when SHMMAX is close to the
total size of physical memory.

--
Peter Eisentraut   peter_e@gmx.net   http://funkturm.homeip.net/~peter


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