From: Frank Joerdens <frank@joerdens.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Ryan Hansen <ryan.hansen@brightbuilders.com>
Cc: pgsql-performance@postgresql.org, "Nic Ferrier" <nic@woome.com>
Cc: Mike Rogers <mikero@woome.com>
Cc: Karl Tilbury <karl@woome.com>
Subject: Re: Memory Allocation (8 GB shared buffer limit on Ubuntu Hardy)
Date: Wed, 7 Jan 2009 04:46:22 +0100
Message-ID: <7d10d2df0901061946g4e55fe42g99cb7d7c166b17ab@mail.gmail.com> (raw)
In-Reply-To: <15854.1231294993@sss.pgh.pa.us>
References: <7d10d2df0901061820v29755576p75a92bd1282f34c2@mail.gmail.com>
<15854.1231294993@sss.pgh.pa.us>
On Wed, Jan 7, 2009 at 3:23 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> "Frank Joerdens" <frank@joerdens.de> writes:
>> then I take the request size value from the error and do
>> echo 8810725376 > /proc/sys/kernel/shmmax
>> and get the same error again.
>
> What about shmall?
Yes that works, it was set to
root@db04:~# cat /proc/sys/kernel/shmall
2097152
root@db04:~# getconf PAGE_SIZE
4096
which is 2097152 * 4096 = 85899345920 (presumably a Ubuntu default),
i.e. slightly less than the required shmmax, which explains why 7 GB
works but 8 doesn't. 8810725376 / 4096 = 2151056 would appear to be
right, and indeed after doing
root@db04:~# echo 2151056 > /proc/sys/kernel/shmall
it works.
Thanks!
Frank
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To: pgsql-performance@postgresql.org
Cc: frank@joerdens.de, tgl@sss.pgh.pa.us, ryan.hansen@brightbuilders.com, nic@woome.com, mikero@woome.com, karl@woome.com
Subject: Re: Memory Allocation (8 GB shared buffer limit on Ubuntu Hardy)
In-Reply-To: <7d10d2df0901061946g4e55fe42g99cb7d7c166b17ab@mail.gmail.com>
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