Hi,
For any version of eBS, optimizer_adaptive_features=FALSE
and _optimizer_autostats_job=FALSE are 2 mandatory parameters.
Setting them to FALSE will also ensure the extended statistics based on
directives will not be collected (as that functionality is disabled).
Theoretically, the best could be to delete all statistics and directives
from this DB and then collect fresh statistics by using the "Gather %
Stats" concurrent programs.
The bad news is that some of the queries may actually benefit from the
additional statistics you already have, and the performance may degrade
after they are wiped.
regards,
---
Maris Elsins
@MarisElsins <https://twitter.com/MarisElsins>
www.facebook.com/maris.elsins
On Fri, Feb 24, 2017 at 5:09 PM, Jonathan Lewis <jonathan@xxxxxxxxxxxxxxxxxx
wrote:
Since you're on 12.1.0.2 it might be the last stage of:
http://jonathanlewis.wordpress.com/2016/08/02/adaptive-mayhem/
Regards
Jonathan Lewis
________________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx <oracle-l-bounce@xxxxxxxxxxxxx> on
behalf of Hameed, Amir <Amir.Hameed@xxxxxxxxx>
Sent: 24 February 2017 14:55:07
To: oracle-l@xxxxxxxxxxxxx
Subject: Extended database statistics
Hi,
The Oracle database version is 12c (12.1.0.2). The application is Oracle
E-Business Suite.
While working on a performance issue, we discovered that there were a lot
of extended statistics present in the database for standard EBS tables. We
do not create extended statistics on any table as part of our statistics
gathering process. The following parameters were set to TRUE:
optimizer_adaptive_features
optimizer_adaptive_reporting_only
I am trying to understand the following:
1. Does Oracle collect extended statistics automatically if the
optimizer_adaptive_features parameter is set to TRUE?
2. Is there a way to find out from the explain plan if extended
statistics were used in the plan?
Thank you,
Amir
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