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RE: script to see explain plan

From: <ryan_gaffuri_at_comcast.net>
Date: Fri, 06 Oct 2006 03:44:33 +0000
Message-Id: <100620060344.20453.4525D120000ED63900004FE52200762302079D9A00000E09A1020E979D@comcast.net>


We have been running into repeated cases when we join a regular table to a GTT where we get a different explain plan than we get an actual plan in a trace file.

I believe Cary showed a case 1-2 years ago where if you have a column that has an index on a number field and you pass it a varchar in a bind variable you can get the wrong plan.

How often do people see inaccuracies in the explain plan?

> One detail that may seem subtle, but it's important. Notice that EXPLAIN
> PLAN doesn't show an execution plan, it shows a *predicted* execution
> plan. Contrast this to the notion that there's a real execution plan in
> your trace data (if you've activated it) or in your V$ fixed views, but
> only after having executed the query in question.
>
>
> Cary Millsap
> Hotsos Enterprises, Ltd.
> http://www.hotsos.com
> Nullius in verba
>
> Hotsos Symposium 2007 / March 4-8 / Dallas
> Visit www.hotsos.com for curriculum and schedule details...
>
> -----Original Message-----
> From: oracle-l-bounce_at_freelists.org
> [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Wojciech Skrzynecki
> Sent: Thursday, October 05, 2006 4:04 PM
> To: oracle-l
> Subject: script to see explain plan
>
> Hello Everybody
>
>
> I would like ask you to about explain plan. I am looking for the best
> script to see explain plan. I know that it is possible to see explain
> plan for active session of other users. I use script from metalink
> Note:260942.1. Maybe you use better scripts to see explain plan.
>
>
> --
> Wojciech Skrzynecki
> Database Administrator
> --
> http://www.freelists.org/webpage/oracle-l
>
>
> --
> http://www.freelists.org/webpage/oracle-l
>
>

--
http://www.freelists.org/webpage/oracle-l
Received on Thu Oct 05 2006 - 22:44:33 CDT

Original text of this message

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