1. 先查看哪些表被锁住了。
select b.owner,
       b.object_name,
       a.session_id,
       a.locked_mode from v$locked_object a,
       dba_objects b where b.object_id = a.object_id;

2. 获取sid,serial
select b.username, b.sid, b.serial#, logon_time
  from v$locked_object a, v$session b
 where a.session_id = b.sid
 order by b.logon_time;

3. 杀死锁进程
alter system kill session 'sid, serial';
如果有ora-00031错误，则在后面加immediate;
很多情况下没法直接杀死session, 需要到数据库服务器杀服务器进程。
通过下面sql查服务器进程
SELECT a.username, c.spid AS os_process_id, c.pid AS oracle_process_id
FROM v$session a, v$process c
 WHERE c.addr = a.paddr
   and a.sid ='250'
   and a.serial# ='14558';

到这里锁应该就被清除了。

——————————————————————————————————————————————————————————————————
查找锁定的session
SELECT   sn.username,m.SID,sn.SERIAL#, m.TYPE,  
        DECODE (m.lmode,  
                0, 'None',  
                1, 'Null',  
                2, 'Row Share',  
                3, 'Row Excl.',  
                4, 'Share',  
                5, 'S/Row Excl.',  
                6, 'Exclusive',  
                lmode, LTRIM (TO_CHAR (lmode, '990'))  
               ) lmode,  
        DECODE (m.request,  
                0, 'None',  
                1, 'Null',  
                2, 'Row Share',  
                3, 'Row Excl.',  
                4, 'Share',  
                5, 'S/Row Excl.',  
                6, 'Exclusive',  
                request, LTRIM (TO_CHAR (m.request, '990'))  
               ) request,  
        m.id1, m.id2  
    FROM v$session sn, v$lock m  
   WHERE (sn.SID = m.SID AND m.request !=0)        --存在锁请求，即被阻塞  
     OR (    sn.SID =m.SID                         --不存在锁请求，但是锁定的对象被其他会话请求锁定  
         AND m.request = 0  
         AND lmode != 4  
         AND (id1, id2) IN (  
                       SELECT s.id1, s.id2  
                         FROM v$lock s  
                        WHERE request != 0 AND s.id1 = m.id1  
                              AND s.id2 = m.id2)  
        )  
ORDER BY id1, id2, m.request;


通过数据字典v$session 与v$lock 来了解正在等待锁资源的用户
select a.username,a.sid,a.serial#,b.id1 from v$session a ,v$lock b   
where a.lockwait = b.kaddr;

了解锁住其他用户的用户进程：
select a.username,a.sid,a.serial#,b.id1 from v$session a,v$lock b   
        where b.id1 in  
                (select distinct e.id1 from v$session d,v$lock e where d.lockwait =e.kaddr)   
                And a.sid = b.sid and b.request =0;