| From: | "Frank Joerdens" <frank(at)joerdens(dot)de> |
|---|---|
| To: | "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | "Ryan Hansen" <ryan(dot)hansen(at)brightbuilders(dot)com>, pgsql-performance(at)postgresql(dot)org, "Nic Ferrier" <nic(at)woome(dot)com>, "Mike Rogers" <mikero(at)woome(dot)com>, "Karl Tilbury" <karl(at)woome(dot)com> |
| Subject: | Re: Memory Allocation (8 GB shared buffer limit on Ubuntu Hardy) |
| Date: | 2009-01-07 03:46:22 |
| Message-ID: | 7d10d2df0901061946g4e55fe42g99cb7d7c166b17ab@mail.gmail.com |
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| Lists: | pgsql-performance |
On Wed, Jan 7, 2009 at 3:23 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> "Frank Joerdens" <frank(at)joerdens(dot)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(at)db04:~# cat /proc/sys/kernel/shmall
2097152
root(at)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(at)db04:~# echo 2151056 > /proc/sys/kernel/shmall
it works.
Thanks!
Frank
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