Date: Fri, 10 Dec 2010 00:15:14 +0100 From: Laszlo Nagy <gandalf@shopzeus.com> To: Bill Moran <wmoran@potentialtech.com> Cc: questions@freebsd.org, danieleff@gmail.com Subject: Re: What is loading my server so much? Message-ID: <4D016302.70505@shopzeus.com> In-Reply-To: <20101209083818.e622a146.wmoran@potentialtech.com> References: <4D00BDF8.6020206@shopzeus.com> <20101209083818.e622a146.wmoran@potentialtech.com>
next in thread | previous in thread | raw e-mail | index | archive | help
> First off, you have 24G of RAM available and PostgreSQL only seems to
> have access to 400M of it. Bump shared_buffers up to 2 or 3 G at least,
> and bump up work_mem to at least a few hundred meg, and
> maintenance_work_mem up to at 1/2G or so.
All right. Here is what I did. I setup a new shmmax value this way:
sysctl kern.ipc.shmmax=8589934592
It is 8G. (By the way I also have kern.ipc.shm_use_phys: 1 ) Then I
have changed shared_mem to 1024MB in postgresql.conf.
Then I tried to start postgresql I got this message in the log:
Dec 9 17:53:59 shopzeus postgres[27247]: [1-4] The PostgreSQL
documentation contains more information about shared memory configuration.
Dec 9 17:55:52 shopzeus postgres[27328]: [1-1] FATAL: could not create
shared memory segment: Cannot allocate memory
Dec 9 17:55:52 shopzeus postgres[27328]: [1-2] DETAIL: Failed system
call was shmget(key=5432001, size=1105051648, 03600).
Dec 9 17:55:52 shopzeus postgres[27328]: [1-3] HINT: This error
usually means that PostgreSQL's request for a shared memory segment
exceeded available memory or swap space. To reduce the request size
(currently 1105051648 bytes), reduce PostgreSQL's shared_buffers
parameter (currently 131072) and/or its max_connections parameter
(currently 203).
Dec 9 17:55:52 shopzeus postgres[27328]: [1-4] The PostgreSQL
documentation contains more information about shared memory configuration.
I do not understand.
Doc says these:
"max_connections cost ~ 400 bytes of shared memory slot, plus lock space
(see max_locks_per_transaction)."
Even if I had max_connections = 5000, total shared memory required would
be way below shmmax=8G.
What am I missing here?
Thanks
Laszlo
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?4D016302.70505>