From: Alan Hodgson <ahodgson@simkin.ca>
Organization: Simkin Network Consulting
To: pgsql-performance@postgresql.org
Subject: Re: CPU Usage
Date: Tue, 13 Feb 2007 10:48:25 -0800
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On Tuesday 13 February 2007 10:36, "Campbell, Lance" <lance@uiuc.edu> 
wrote:
> We have 12+ schemas in 1 database. When I do a unix "top" command I
> notice one postmaster process has 100% CPU usage.  This process just
> stays at 100% to 99% CPU usage.  There are other postmaster processes
> that pop up.  They use hardly no CPU or memory.  They also disappear
> very fast.  I am wondering, is postgres only using one processor for
> database queries?  Is there something I need to do to tell postgres
> to use more than one processor?  Or does postgres only use up to one
> processor for any particular database?

Each connection to the cluster gets a dedicated backend process, which 
can only be scheduled on one processor at a time.  So, in effect, a 
single query can only use one processor at a time, but any number of 
other backends can be simultaneously using the other CPUs.  It does not 
matter which database they are operating on.

-- 
"It is a besetting vice of democracies to substitute public opinion for
law." - James Fenimore Cooper