Date: Sun, 17 Jun 2007 00:30:15 -0400
From: Robert Treat <xzilla@users.sourceforge.net>
Subject: Re: Performance Monitoring
In-reply-to: <Pine.GSO.4.64.0706151318480.5871@westnet.com>
To: pgsql-hackers@postgresql.org
Cc: Greg Smith <gsmith@gregsmith.com>
Message-id: <200706170030.16112.xzilla@users.sourceforge.net>
MIME-version: 1.0
Content-type: text/plain; charset=iso-8859-1
Content-transfer-encoding: 7bit
Content-disposition: inline
References: <BAY104-W14579231F227BCEBB31D7DCD1E0@phx.gbl>
	<Pine.GSO.4.64.0706151318480.5871@westnet.com>
User-Agent: KMail/1.9.1

On Friday 15 June 2007 13:29, Greg Smith wrote:
> On Fri, 15 Jun 2007, Umar Farooq wrote:
> > Surprisingly, no matter what type of query I execute, when I use strace
> > to monitor the system calls generated they turn out to be the same for
> > ALL sorts of queries.
>
> How are you calling strace?  The master postgres progress forks off new
> processes for each of the clients, you need to make sure you include stats
> from all of them as well to get anything.
>
> I normally use
>
> strace -c -f -p [main postgres process]
>
> which is helpful to collecte basic info, but even that's not quite right;
> you don't get the work done by the other proceses (logger, writer, stats
> collector).  To get everything, you need to start some process that you
> attach strace to like this, then have that process start the server.
>
> I haven't found strace to be a great tool for this type of work.  You
> might take at look at systemtap instead (
> http://sourceware.org/systemtap/wiki ) which is a bit immature but is
> going the right direction.
>
> I will now bow my head and wait for someone to suggest you move to an OS
> that supports dtrace.
>

You know that's what I was thinking :-)

-- 
Robert Treat
Build A Brighter LAMP :: Linux Apache {middleware} PostgreSQL