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Re: Seeking advice on potential 10g upgrade

From: Niall Litchfield <niall.litchfield_at_gmail.com>
Date: Tue, 29 Aug 2006 09:52:34 +0100
Message-ID: <7765c8970608290152x49ce8d30s71a66463d647a07e@mail.gmail.com>


I'd take a look at http://www.jlcomp.demon.co.uk/hinted_sql.html for some further discussion of whether the system is likely to be more stable or run into issues in the presence of many hinted sql statements.

Plan Stability is indeed a set of hints, its the main evidence that I use when I state that a hint is a directive, rather than a 'hint' in the english sense of the word, it's worth noting however the number of hints that Plan Stability tends to find necessary to produce a locked in execution plan, and compare to the typical use of hints by developers. for example many developers would write code like

select
/*+ USE_NL(a,b) */ <cols>
from
a, b
where <criteria>

and consider that this ensured that Oracle would use a nested loops join for the query.

On 8/28/06, Allen, Brandon <Brandon.Allen_at_oneneck.com> wrote:
> With all due respect I have to disagree with you on that. In many cases
> hints can make query execution more stable. After all - Oracle's own
> "Plan Stability" feature (a.k.a Stored Outlines) is really just a bunch
> of persistent internal hints. So, it depends on what hints are used,
> but if they are just simple index and join method hints - they might
> actually make things more stable/predictable through an upgrade.
>
>
> > -----Original Message-----
> > From: oracle-l-bounce_at_freelists.org
> > [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Kevin Closson
> > Sent: Monday, August 28, 2006 11:56 AM
> > To: oracle-l_at_freelists.org
> > Subject: RE: Seeking advice on potential 10g upgrade
> >
> > >>>I know that they have made liberal use of optimizer
> > hints, and I'm afraid that those may cause us grief if we upgrade.
> >
> > ...that's a good bet.
> >
> >
> > --
> > http://www.freelists.org/webpage/oracle-l
> >
> >
> >
>
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-- 
Niall Litchfield
Oracle DBA
http://www.orawin.info
--
http://www.freelists.org/webpage/oracle-l
Received on Tue Aug 29 2006 - 03:52:34 CDT

Original text of this message

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