Re: [PERFORM] 7.3.2 pg_restore very slow

Hi Richard,

Thank you very much for the information. The SHMMAX was set to 33554432, and that's why it failed to start the postmaster. Thanks for the link to the kernel resources article. I guess changing these parameters would require recompiling the kernel.

Is there any work around without changing these parameters to make maximum use of RAM?

We got a new server now with 2GB RAM, but it also has the same value for SHMMAX.

And I am trying the restore with the following conf
sort_mem = 40960 (changed from 1024)
shared_buffers = 3000 (changed from 64)
max_connections = 128 (changed from 32)

Thanks,
Saranya




Richard Broersma Jr <rabroersma(at)yahoo(dot)com> wrote:

> IpcMemoryCreate: shmget(key=5432001, size=85450752, 03600) failed: Invalid argument
> This error usually means that PostgreSQL's request for a shared memory
> segment exceeded your kernel's SHMMAX parameter. You can either
> reduce the request size or reconfigure the kernel with larger SHMMAX.
> To reduce the request size (currently 85450752 bytes), reduce
> PostgreSQL's shared_buffers parameter (currently 10000) and/or
> its max_connections parameter (currently 128).
> If the request size is already small, it's possible that it is less than
> your kernel's SHMMIN parameter, in which case raising the request size or
> reconfiguring SHMMIN is called for.

if you cat /proc/sys/kernel/shmmax
it will tell you what it is set to. It needs to be at least "85450752". The size that Postgresql
is trying to grab.

also shmall may need to be adjusted also.

> The total RAM available on this machine is 512MB.
>
> I am not sure how to set these parameters SHMMAX and SHMMIN.
> Any help/advice would be greatly appreciated.

http://www.postgresql.org/docs/8.1/interactive/kernel-resources.html
This will help you to set the kernel parameters.

Regards,

Richard Broersma Jr.

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