解决方法如下：

=========================================================

SQL> select session_id from v$locked_object;

SESSION_ID
----------
       56

SQL> SELECT sid, serial#, username, osuser FROM v$session where sid = 56;

       SID    SERIAL# USERNAME                       OSUSER
---------- ---------- ------------------------------ ------------------------------
       56         2088 ghb                          fy

SQL> ALTER SYSTEM KILL SESSION ‘56,2088‘;

System altered