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Date:      Thu, 13 Dec 2001 17:55:56 +0000
From:      Simon Dick <simond@irrelevant.org>
To:        Joe Koenig <joe@jwebmedia.com>
Cc:        freebsd-questions@FreeBSD.ORG
Subject:   Re: shmmax? (PostgreSQL Help Please)
Message-ID:  <20011213175556.GC380@irrelevant.org>
In-Reply-To: <3C18ECE9.D7E2AF57@jwebmedia.com>
References:  <Pine.SOL.4.21.0112131443180.9407-100000@acmex.gatech.edu> <3C18C3EC.581AD09A@jwebmedia.com> <20011213163813.D68324@pcwin002.win.tue.nl> <3C18ECE9.D7E2AF57@jwebmedia.com>

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You're meant to create your own /etc/sysctl.conf if there's not one
present, if you edit the one in /usr/src then it'll a) get overwritten
when you next cvsup and b) not be used in the first place :)

(see also sysctl.conf(5) )

On Thu, Dec 13, 2001 at 12:01:12PM -0600, Joe Koenig wrote:
> This seemed like it was the best response I got but I have no
> /etc/sysctl.conf, but I did find that file in /usr/src/etc, so I edited
> that to include my change. I restarted my machine and the settings did
> not change. Even so, I was able to change shmall for the time being,
> changed postgres' shared_buffers to 15200 and postgres would not start
> until I uncommented the line. Anyone here experienced with optimizing
> postgres and would be able to help me get the shared_buffers of postgres
> up? Thanks,
> 
> Joe
> 
> Stijn Hoop wrote:
> > 
> > On Thu, Dec 13, 2001 at 09:06:19AM -0600, Joe Koenig wrote:
> > > I checked my LINT file and I've got the same SHMALL=1025. Doesn't that
> > > seem awefully small? My system as 1G of RAM and the article on
> > > optimizing postgresql recommended 128M for a system with 512M total. Any
> > > idea on a reasonable setting for SHMMAXPGS. Also, does the kernel need
> > > to be re-built and installed after changing this file, or will a reboot
> > > do the trick? I was reading about creating a custom kernel and in there
> > > is the option to use or not use shared memory, but nothing about the
> > > LINT file was ever mentioned. I didn't know if those values got built
> > > into the kernel on a make, or if they were read in at reboot. Any
> > > information is appreciated. Thanks!
> > 
> > You can check on your defaults with sysctl:
> > 
> > [stijn@pcwin002] <~> sysctl -a | grep shm
> > kern.ipc.shmmax: 33554432
> > kern.ipc.shmmin: 1
> > kern.ipc.shmmni: 192
> > kern.ipc.shmseg: 128
> > kern.ipc.shmall: 8192
> > kern.ipc.shm_use_phys: 0
> > 
> > You can change them at runtime using sysctl -w:
> > 
> > [stijn@pcwin002] <~> sudo sysctl -w kern.ipc.shmmin=1
> > kern.ipc.shmmin: 1 -> 1
> > 
> > I'm not sure if all these values can be tuned however.
> > 
> > Put changes in /etc/sysctl.conf to keep them permanent.
> > 
> > HTH,
> > 
> > --Stijn
> > 
> > --
> > "Linux has many different distributions, meaning that you can probably find
> > one that is exactly what you want (I even found one that looked like a Unix
> > system)."
> >                 -- Mike Meyer, freebsd-questions@freebsd.org,
> >                         in message <15252.28617.61423.224978@guru.mired.org>
> > 
> > To Unsubscribe: send mail to majordomo@FreeBSD.org
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> 
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> 

-- 
Simon Dick					simond@irrelevant.org
"Why do I get this urge to go bowling everytime I see Tux?"

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