Re: Shared memory usage

From: Adam Tauno Williams <adamtaunowilliams(at)gmail(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Shared memory usage
Date: 2007-08-27 10:21:43
Message-ID: 1188210103.4723.4.camel@aleph.wmmi.net
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> I have a postgres 8.0 and ~400mb database with lots of simple selects
> using indexes.
> I've installed pgpool on the system. I've set num_init_children to 5 and
> here is the top output.
> One of postmasters is my demon running some insert/update tasks. I see
> that they all use cpu heavily, but do not use the shared memory.
> shared_buffers is set to 60000, yet they use a minimal part of that. I'd
> like to know why won't they use more?

This just looks like the output of top; what is telling you that
PostgreSQL is not using the shared memory? Enable statistics collection
and then look in pg_statio_user_tables.

> top - 00:12:35 up 50 days, 13:22, 8 users, load average: 4.84, 9.71,
> 13.22
> Tasks: 279 total, 10 running, 268 sleeping, 1 stopped, 0 zombie
> Cpu(s): 50.0% us, 12.9% sy, 0.0% ni, 33.2% id, 1.8% wa, 0.0% hi, 2.1%
> si
> Mem: 6102304k total, 4206948k used, 1895356k free, 159436k buffers
> Swap: 1959888k total, 12304k used, 1947584k free, 2919816k cached
> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
> 11492 postgres 16 0 530m 72m 60m S 14 1.2 0:50.91 postmaster
> 11493 postgres 16 0 531m 72m 60m R 14 1.2 0:48.78 postmaster
> 11490 postgres 15 0 530m 71m 59m S 13 1.2 0:50.26 postmaster
> 11491 postgres 15 0 531m 75m 62m S 11 1.3 0:50.67 postmaster
> 11495 postgres 16 0 530m 71m 59m R 10 1.2 0:50.71 postmaster
> 10195 postgres 15 0 536m 84m 66m S 6 1.4 1:11.72 postmaster

--
Adam Tauno Williams, Network & Systems Administrator
Consultant - http://www.whitemiceconsulting.com
Developer - http://www.opengroupware.org

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