MacOS X Shared Buffers (SHMMAX)? 
Author Message
 MacOS X Shared Buffers (SHMMAX)?

Good day,

Does anyone have any experience in increasing the amount of shared memory
buffers available to Mac OS X/Darwin? When starting with more than 128
backend connections on a test G3 I encounter:

-----------------------------------------------------------------------------------
IpcMemoryCreate: shmget(key=5432001, size=33357824, 03600) failed: Invalid argument

This error usually means that PostgreSQL's request for a shared memory
segment exceeded your kernel's SHMMAX parameter.  You can either
reduce the request size or reconfigure the kernel with larger SHMMAX.
-----------------------------------------------------------------------------------

However, I can find no helpful information looking around for how Darwin
handles this configuration. Hopefully it does not require a recompile of
the Kernel. ;)

Any knowledge on this topic would be greatly appreciated.

Best Regards,
Jw.
--


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Sat, 06 Nov 2004 09:45:47 GMT
 MacOS X Shared Buffers (SHMMAX)?



Quote:
> Good day,

> Does anyone have any experience in increasing the amount of shared memory
> buffers available to Mac OS X/Darwin? When starting with more than 128
> backend connections on a test G3 I encounter:

> ------------------------------------------------------------------------------
> -----
> IpcMemoryCreate: shmget(key=5432001, size=33357824, 03600) failed: Invalid
> argument

> This error usually means that PostgreSQL's request for a shared memory
> segment exceeded your kernel's SHMMAX parameter.  You can either
> reduce the request size or reconfigure the kernel with larger SHMMAX.
> ------------------------------------------------------------------------------
> -----

> However, I can find no helpful information looking around for how Darwin
> handles this configuration. Hopefully it does not require a recompile of
> the Kernel. ;)

Actually --- :-> I'm no expert on this topic, but Darwin is BSD and I do
recall a post on this very topic, to the effect that the poster believed
some flavors of BSD, possibly MOSX included, do require rebuilding the
kernel to change this value.

As a MOSX user I'd certainly love to be found wrong.

-- sgl

=======================================================
Steve Lane

Vice President
Chris Moyer Consulting, Inc.
833 West Chicago Ave Suite 203


Fax:   (312) 850-3930       Web:   http://www.fmpro.com
=======================================================

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Sat, 06 Nov 2004 11:07:33 GMT
 MacOS X Shared Buffers (SHMMAX)?

Quote:
> Does anyone have any experience in increasing the amount of shared memory
> buffers available to Mac OS X/Darwin?

A little bit of googling turns up Apple bug reports stating that OSX
has a hardwired limit on shared memory --- so no, short of modifying
and recompiling the kernel, you're outta luck.

                        regards, tom lane

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Sat, 06 Nov 2004 11:10:40 GMT
 
 [ 3 post ] 

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