Tracing other's session in 10g

To trace the other user's session in Oracle 10g,

Step 1: Set the init parameter.

SQL> Alter system set TIMED_STATISTICS = TRUE;
SQL> Alter system set MAX_DUMP_SIZE = UNLIMITED;
SQL> Alter system set TRACEFILE_IDENTIFIER = ‘mytrace’;

Step 2: Enable Tracing

SQL> Exec DBMS_MONITOR.session_trace_enable(149,3643, TRUE, TRUE);
Where
1st Parameter: Session ID. (null means current session’s ID)
2nd Parameter: Serial # (null means current session’s serial#)
3rd Parameter: Trace Waits (Default True)
4th Parameter: Bind Variables (Default False)

Step 3: Disable Tracing

SQL> Exec DBMS_MONITOR.SESSION_TRACE_DISABLE(149,3643);

Thanks