RE: script to see explain plan
- From: "Siva Valiveru" <SValiveru@xxxxxxxxxxxxx>
- To: <ryan_gaffuri@xxxxxxxxxxx>, <cary.millsap@xxxxxxxxxx>, <wojciech.skrzynecki@xxxxxxxxx>, "oracle-l" <oracle-l@xxxxxxxxxxxxx>
- Date: Thu, 5 Oct 2006 21:10:30 -0700
One case actual execution plan do bind peeking where as explain plan
does not, that can differ plan for first time execution. If you are
running into case where actual plan differ from explain plan/set
autotrace may be use the method shown below.
http://www.jlcomp.demon.co.uk/faq/how_to_explain.html
________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of
ryan_gaffuri@xxxxxxxxxxx
Sent: Thursday, October 05, 2006 8:45 PM
To: cary.millsap@xxxxxxxxxx; wojciech.skrzynecki@xxxxxxxxx; oracle-l
Cc: Cary Millsap
Subject: RE: script to see explain plan
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?
-------------- Original message --------------
From: "Cary Millsap" <cary.millsap@xxxxxxxxxx>
> 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@xxxxxxxxxxxxx
> [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Wojcie ch
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
> --
> //www.freelists.org/webpage/oracle-l
>
>
> --
> //www.freelists.org/webpage/oracle-l
>
>
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