how to revoke dbms_logmnr.start_logmnr()

i run this sql to find out which user made changes to a table ( add a col):

   SELECT username,operation,sql_redo
    from v$logmnr_contents
      where operation = 'DDL'
SQL> from v$logmnr_contents

     *
ERROR at line 2:
ORA-01306: dbms_logmnr.start_logmnr() must be invoked before selecting from v$logmnr_contents

Pls tell me how to revoke dbms_logmnr.start_logmnr() .

TQ!

regards,
Tracy Received on Fri Mar 12 2004 - 21:33:48 CST