Re: Issues with OSX and SHMMAX?

Steve Atkins <steve(at)blighty(dot)com> writes:
> On Apr 22, 2013, at 11:19 AM, Josh Berkus <josh(at)agliodbs(dot)com> wrote:
>> On 04/21/2013 02:33 PM, Evgeny Shishkin wrote:
>>> On Apr 22, 2013, at 1:29 AM, Josh Berkus <josh(at)agliodbs(dot)com> wrote:
>>>> I've heard a rumor that the most recent update of OSX "mountain lion"
>>>> lowers the installed SHMMAX to 4MB, which prevents PostgreSQL from
>>>> installing. Can anyone verify this?

>>> kern.sysv.shmmax: 4194304

>> That would be 4MB. Can anyone else verify this?

> It's the default setting on my 10.8.3 box. (I'm setting it higher in
> /etc/sysctl.conf and have no problems, but it stopped postgres.app
> starting when I removed that).

AFAIR, the default setting has been that or lower in every previous
version of OSX, so it seems unlikely that mountain lion per se broke
anything. It might've appeared that way if you did a reinstall and
forgot to copy your old /etc/sysctl.conf.

A different theory, if things used to work and now don't, is that
somewhere recently we crossed a threshold in memory usage between
"will start at 4MB" and "won't start at 4MB". If so, 9.3 ought to
make things better (since we're mostly getting out from under SysV
shared memory limits), but in existing releases manually fixing
the limit will be the only recourse.

regards, tom lane