Re: was there a change in FreeBSD SHM implementation from

On Wed, 10 Jul 2002, Vivek Khera wrote:

> -- cut here --
> IpcMemoryCreate: shmget(key=5432001, size=665346048, 03600) failed: Cannot allocate memory
>
> This error usually means that PostgreSQL's request for a shared
> memory segment exceeded available memory or swap space.
> To reduce the request size (currently 665346048 bytes), reduce
> PostgreSQL's shared_buffers parameter (currently 80000) and/or
> its max_connections parameter (currently 48).
> -- cut here --
>
>
> Now, by my arithmetic, 665346048 is certainly less than 1073741824 by
> quite a bit.
>
> I did not recompile postgres after the FreeBSD upgrade.
>
> Has something changed from 4.4-STABLE that would cause such a failure?
>
> The funny thing is that it worked just fine with FBSD 4.4 and the
> lower setting of shmmax (even with 100000 shared_buffers), so
> something is making postgres try to allocate a larger hunk of memory.
> I just don't know what.
>
> Any advice would be appreciated.

Have you looked at the FreeBSD section here:

   http://www.postgresql.org/idocs/index.php?kernel-resources.html

Most notably, I had to increase SHMMAXPGS on one of my FreeBSD machines.
There doesn't appear to be a sysctl variable for it.

Vince.
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