Re: Question about maintenance_work_mem and shared_buffer

[Rodrigo Barboza <rodrigombufrj@xxxxxxxxx>]

On Wed, May 22, 2013 at 6:14 AM, Albe Laurenz <laurenz.albe@xxxxxxxxxx> wrote:

Rodrigo Barboza wrote:
> I have a doubt.
> I have a 32-bit postrgesql running with 2.5gb of shared_buffer.
> And I have maintenance_work_mem = 1gb and autovacuum_max_workers = 3.
> How maintenance_work_mem is related to shared_buffer?
> If the 3 workers uses 1gb, will the database crash?
> Or their memory usage are separated from each other?

Your doubt is quite in place, as a process on a 32-bit architecture
cannot address more than 4GB of memory.

See http://rhaas.blogspot.jp/2011/05/sharedbuffers-on-32-bit-systems.html

shared_buffers plus the private memory of a backend shouldn't
exceed 3GB.

So I'd go for shared_buffers = 2GB and maintenance_work_mem much
smaller than 1GB.

Yours,
Laurenz Albe

Perfect.

Thanks, guys!