o  To use the RMU Show Optimizer_Statistics command for a
       database, you must have the RMU$ANALYZE or RMU$SHOW privilege
       in the root file access control list (ACL) for the database or
       the OpenVMS SYSPRV or BYPASS privilege.

    o  Cardinality statistics are automatically maintained by
       Oracle Rdb. Physical storage and Workload statistics are only
       collected when you issue an RMU Collect Optimizer_Statistics
       command. To get information about the usage of Physical
       storage and Workload statistics for a given query, define
       the RDMS$DEBUG_FLAGS logical name to be "O". For example:

       $ DEFINE RDMS$DEBUG_FLAGS "O"

       When you execute a query, if workload and physical statistics
       have been used in optimizing the query, you will see a line
       such as the following in the command output:

       ~O: Workload and Physical statistics used

    o  Use the RMU Show Optimizer Statistics command with the
       Statistics=Cardinality/Full/Threshold=n qualifier to identify
       index prefix cardinality drift. This command identifies
       indexes that need to be repaired. Use the RMU Collect
       Optimizer_Statistics command to repair the stored index prefix
       cardinality values.