Query execution plan change in oracle 11G

Hello

Why the plan of execution for the same request launched  in parallel but can change?
How to resolve of problem because there is an impact on the performances?
Thanks
bibi
bibi92Asked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

QlemoBatchelor, Developer and EE Topic AdvisorCommented:
Most probably you have no accurate table and index stats. Try refreshing them:
  exec dbms_stats.gather_schema_stats()
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
bibi92Author Commented:
How can see that I have no accurate table and index stats on oracle 11G?
Thanks
bibi
0
QlemoBatchelor, Developer and EE Topic AdvisorCommented:
This should get you started:
   SELECT table_name, last_analyzed FROM user_tables;
   SELECT table_name, index_name, last_analyzed FROM user_indexes;
0
bibi92Author Commented:
Thanks bibi
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Oracle Database

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.