To: Gavin Kistner <phrogz@mac.com>
cc: pgsql-admin@postgresql.org
Subject: Re: Fresh build on OS X not working (memory) 
In-reply-to: <88181C2E-01CD-417C-8266-D5C9AF570C27@mac.com> 
References: <88181C2E-01CD-417C-8266-D5C9AF570C27@mac.com>
Comments: In-reply-to Gavin Kistner <phrogz@mac.com>
	message dated "Thu, 29 Apr 2010 23:32:10 -0600"
Date: Fri, 30 Apr 2010 01:42:20 -0400
Message-ID: <15253.1272606140@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

Gavin Kistner <phrogz@mac.com> writes:
> Mac OS X 10.6.3
> Built and installed PG 8.4.3 from source
> Trying to start the server, I get "could not create shared memory segment: Invalid argument".

OSX is *notoriously* unfriendly about configuring shm parameters.
You look at it sidewise, it doesn't work, and generally won't tell
you why it's refusing to talk to you.  We document a few of the known
constraints in our manual, but I'm sure there are more.

> Slim2:pgsql _postgres$ sysctl -a | grep shm
> kern.sysv.shmmax: 2147483648
> kern.sysv.shmmin: 1
> kern.sysv.shmmni: 32
> kern.sysv.shmseg: 8
> kern.sysv.shmall: 2147483648

Hm.  That shmall setting is not sane at all (remember the units are
pages).  I wonder whether you've forced some internal overflow inside
the kernel.  For comparison, I have these settings on my laptop:

pro:~ tgl$ cat /etc/sysctl.conf 
kern.sysv.shmmax=33554432
kern.sysv.shmmin=1
kern.sysv.shmmni=32
kern.sysv.shmseg=8
kern.sysv.shmall=8192

and PG starts fine for me.

			regards, tom lane