Query execution plan change in oracle 11G


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

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bibi92Author Commented:
How can see that I have no accurate table and index stats on oracle 11G?
Qlemo"Batchelor", 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;
bibi92Author Commented:
Thanks bibi
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