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* CPU Usage
@ 2007-02-13 18:36 Campbell, Lance <lance@uiuc.edu>
0 siblings, 1 reply; 2+ messages in thread
From: Campbell, Lance @ 2007-02-13 18:36 UTC (permalink / raw)
To: pgsql-performance
Postgres 8.1
Linux Redhat AS 4.X
4 processor box
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?
Thanks for your help,
Lance Campbell
Project Manager/Software Architect
Web Services at Public Affairs
University of Illinois
217.333.0382
http://webservices.uiuc.edu
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: CPU Usage
@ 2007-02-13 18:48 Alan Hodgson <ahodgson@simkin.ca>
parent: Campbell, Lance <lance@uiuc.edu>
0 siblings, 0 replies; 2+ messages in thread
From: Alan Hodgson @ 2007-02-13 18:48 UTC (permalink / raw)
To: pgsql-performance
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
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2007-02-13 18:36 CPU Usage Campbell, Lance <lance@uiuc.edu>
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