Oracle Database Discussions

While tracing for a particular session for tkprof getting an error

SQL> EXECUTE DBMS_MONITOR.SESSION_TRACE_ENABLE(session_id => 32,serial_num =>191
23,        waits => TRUE, binds => true);
BEGIN DBMS_MONITOR.SESSION_TRACE_ENABLE(session_id => 32,serial_num =>19123,
    waits => TRUE, binds => true); END;

      *
ERROR at line 1:
ORA-06550: line 1, column 7:
PLS-00201: identifier 'DBMS_MONITOR.SESSION_TRACE_ENABLE' must be declared
ORA-06550: line 1, column 7:
PL/SQL: Statement ignored