The SQL command we used to manually run is: execute DBMS_STATS. While doing further investigation, we found that BRCONNECT job is set to default value (50% deviation) to update the table statistics.You can access these statistics using data dictionary views.
Oracle decides which type of histogram to use depending of the number of distinct values (NDV) in the column.
Our consultant don't allow us "manually" to run "update statistics".
Consultant say ORACLE 10GR2 automatic update statistics algorithm better than manually command.
The column statistics includes information about the number of distinct values (NDV) as well as the maximum and minimum values.
This information helps the optimizer understand if an equality clause of a query will be selective or not.