Date: Wed, 24 May 2006 08:34:51 +0200 From: "Claus Guttesen" <kometen@gmail.com> To: "Mark Kirkwood" <markir@paradise.net.nz> Cc: freebsd-stable@freebsd.org Subject: Re: PostgreSQL uses more memory on 6.1? Message-ID: <b41c75520605232334ifb3cd59lcd6e562a7cdde323@mail.gmail.com> In-Reply-To: <4473ADF7.4080101@paradise.net.nz> References: <200605231531.18092.kirk@strauser.com> <200605231713.22363.jkim@FreeBSD.org> <200605231719.56164.jkim@FreeBSD.org> <200605231636.27463.kirk@strauser.com> <4473ADF7.4080101@paradise.net.nz>
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> > That did it! Bumping kern.ipc.shmall to 65536 got me back up and runni= ng > > with enough shared_memory to get my jobs done. > > Having not so long ago been caught by this myself, I think the > relationship between shmmax and shmall is worth clarifying: > > $ sysctl -d kern.ipc.shmall > kern.ipc.shmall: Maximum number of pages available for shared memory > $ sysctl -d kern.ipc.shmmax > kern.ipc.shmmax: Maximum shared memory segment size > > So to run 1 Postgres installation with 128Mb of shared memory: > > kern.ipc.shmall=3D32768 > kern.ipc.shmmax=3D134217728 > > However suppose you want to run 2 Postgres installations, each using > 128Mb of shared memory: > > kern.ipc.shmall=3D65536 > kern.ipc.shmmax=3D134217728 > > i.e. maximum system wide shared memory is 65536*4096 =3D 256Mb, but the > maximum size any single segment can be is 128Mb. Thank you. I wasn't aware that one could alter sysctl's. I might dive into that, makes kernel-maintenance a tiny bit easier. regards Claus
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