Re: CPU Usage

From: Alan Hodgson <ahodgson(at)simkin(dot)ca>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: CPU Usage
Date: 2007-02-13 18:48:25
Message-ID: 200702131048.25646@hal.simkin.ca
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On Tuesday 13 February 2007 10:36, "Campbell, Lance" <lance(at)uiuc(dot)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

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