Re: Completely insane execution plan with 11.2.0.3 but not with 11.2.0.2
- From: Greg Rahn <greg@xxxxxxxxxxxxxxxxxx>
- To: thomas.kellerer@xxxxxxxxxx
- Date: Mon, 23 Jul 2012 23:05:55 -0700
1) export statistics from 11.2.0.2 and import them to the 11.2.0.3 db
2) set init.ora parameters identical
3) validate that the issue still exists
4) it yes, then create a test case builder archive of the with OFE=11.2.0.3
(default) and then again with 11.2.0.2 see [1]
5) upload both archives to Oracle support.
If you want, load both optimizer trace files into a visual diff tool and
see where they diverge.
[1] https://raw.github.com/grahn/oracle_scripts/master/tcb.sh
On Mon, Jul 23, 2012 at 8:01 AM, Thomas Kellerer <thomas.kellerer@xxxxxxxxxx
> wrote:
> Hello,
>
> (I have also posted this to forums.oracle.com in case this sounds
> familiar to someone).
>
> we have a production server that is running Oracle 11.2.0.2 on Windows and
> a Development/Test server
> that is running 11.2.0.3 on Linux.
>
> We have one statement that selects from a rather large view (that
> statement does a simple select * from viewname).
> The execution plan shows a cost of ~20k and a row estimate of ~800
>
> On our test server which has similar data the optimizer completely
> mis-estimating the cost for one join which
> results in totally insane estimates higher up the chain. All other row
> estimates are pretty close to reality.
>
> After testing several things we discovered that setting
> optimizer_features_enable = '11.2.0.2' things are fine on our test server.
>
> --
Regards,
Greg Rahn | blog <http://bit.ly/u9N0i8> | twitter <http://bit.ly/v733dJ> |
linkedin <http://linkd.in/gregrahn>
--
//www.freelists.org/webpage/oracle-l
Other related posts:
