Hi, 1) exec dbms_stats.gather_schema_stats(ownname =>'''||username|| ''',degree=>4,cascade =>TRUE,options=>''GATHER STALE''); 2)DBMS_UTILITY.ANALYZE_SCHEMA('USERNAME','COMPUTE'); 3)ANALYZE TABLE <TABLENAME> COMPUTE STATTISTICS FOR ALL INDEXES COLUMNS; Please suggest which is best in case of cost based optimizer in Oracle9i. thanks -- //www.freelists.org/webpage/oracle-l