Re: system stats $ RAC

From: Niall Litchfield <niall.litchfield_at_gmail.com>
Date: Mon, 9 Aug 2004 16:17:00 +0100
Message-ID: <7765c89704080908174e7d3527@mail.gmail.com>

On Mon, 9 Aug 2004 17:55:17 +0300, Tanel P=F5der <tanel.poder.003_at_mail.ee> = wrote:
> > AUX_STAT$ does not have INST_ID in current versions. So there is no way
> > to differentiate the workload patterns across the nodes in the cluster.
> > So I would be little careful in using CPU costing in RAC environments.
>=20
> What if you ran gather_system_stats on each node? Wouldn't it leave insta=
nce
> specific stats in each instances SGA during runtime? (not talking about
> storing stats in aux_stats$ here)

>=20
> Tanel.

I wonder if this is such an issue as it may appear (in RAC not Grid).=20

The IO related system statistics *ought* to be invariant across instances. Then there are the CPU related stats. These ought only to be variant across instances it seems to me if

You have different hardware for each node. (Different as in different models and CPUs) or
You are running other stuff that competes for CPU on some of the nodes. = =20

I wonder if either of the above is entirely wise. =20

If there are other examples of cases where system stats ought to be different then I'd be glad to hear them.

--=20
Niall Litchfield
Oracle DBA
http://www.niall.litchfield.dial.pipex.com

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Received on Mon Aug 09 2004 - 10:13:13 CDT