Antwort: Re: explain plan and the real execution plan

From: Martin Klier <Martin.Klier_at_klug-is.de>
Date: Fri, 20 Nov 2009 17:39:03 +0100
Message-ID: <OF348DA8E3.E3CC98A9-ONC1257674.005B5E17-C1257674.005B7737_at_klug-is.de>



Maybe you want to have a look at this article for EXPLAIN PLANS and EXECUTION PLANS.
Keep in mind, that things like bind peeking won't happen if you generate an EXPLAIN_PLAN! http://www.usn-it.de/index.php/2009/02/26/oracle-explain-or-execution-plans-guess-or-reality/

Best regards
--
Mit freundlichem Gruß

Martin Klier
Senior Oracle Database Administrator


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oracle-l-bounce_at_freelists.org schrieb am 20.11.2009 17:13:59:

> Von:
>
> Yong Huang <yong321_at_yahoo.com>
>
> An:
>
> oracle-l_at_freelists.org
>
> Datum:
>
> 20.11.2009 17:16
>
> Betreff:
>
> Re: explain plan and the real execution plan
>
> Gesendet von:
>
> oracle-l-bounce_at_freelists.org
>
> In addition, if the queries against this table recently started to
> use columns not used before, the content of col_usage$ will change
> thus affecting the stats related to auto generated historgram.
>
> Yong Huang
>
> Tanel Poder wrote:
>
> > 1) The optimizer statistics
> >
> > I assume this database has no change – no ddl and dml. Under this
> > situation, I would say the optimizer statistics would remain the same,
> > correct?
>
> Even if you have no DDL and no DML happening, someone may still have
> gathered optimizer statistics on the tables and changed them. Maybe the
last
>
>
>
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>i0zX+n{+i^
Received on Fri Nov 20 2009 - 10:39:03 CST

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