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Re: Poor Performance after 9i migration on Windows

From: Christian Antognini <>
Date: Fri, 9 Jul 2004 23:40:39 +0200
Message-ID: <>

Hi Mladen

"Mladen Gogala" <> wrote in message
> On Fri, 09 Jul 2004 09:59:01 +0200, Christian Antognini wrote:
> > Application tuning make only sense if the instance is correctly
> > Or do you want to start adding hints to all queries?
> For one, see what are you waiting for, do you have any statistics and
> alike. Then worry about the instance. Speaking of a slow database is
> not a smart thing to do. Database is never slow, applications are. If
> you need help, then give me the information I need to help you. If you
> know the answer, then you don't need this group.

It's not me that asked for help... it's Kalle...

> As I've said before, except in rather extreme cases, the impact of the
> instance parameters is few percents only.

Mhmm... when I spoke from instance parameters, as I wrote in my first post, I mean the optimizer parameters!

> The root cause of the problem is usually fouled up SQL.

As written by Kalle they faced out problems after the migration, i.e. I deduce that before the migration the application was performing well. Now, if the application has not been changed, advising to start with an application tuning is absurd! As I wrote in my first post the problem is usually caused by the optimizer. In fact too many people thinks that they can migrate without modifying the optimizer parameters. The result is that the optimizer generates sub-optimal execution plan. This is no opinion, I faced out this problem many times.

> I have no idea why meddling with the instance
> parameters has such an appeal for beginner DBAs.

I don't consider me a beginner... in fact I use Oracle since 1995.

> To my knowledge, Oracle hasn't yet shipped a version which
> has "_silver_bullet" parameter. That is planed for Oracle 99z.

At least on this point I agree with you.



Received on Fri Jul 09 2004 - 16:40:39 CDT

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