--1.首先查看有哪些锁  --主要是看看有没有自己用户锁的表
select s.username,
       decode(l.type, ‘TM‘, ‘TABLE LOCK‘, ‘TX‘, ‘ROW LOCK‘, null) lock_level,
       o.owner,
       o.object_name,
       o.object_type,
       s.sid,
       s.serial#,
       s.terminal,
       s.machine,
       s.program,
       s.osuser
from v$session s,
     v$lock l,
     dba_objects o
where l.sid = s.sid
  and l.id1 = o.object_id(+)
  and s.username is not null;
  
--2.如果发生了锁等待，看是谁锁了表而引起谁的等待
--以下的语句可以查询到谁锁了表，而谁在等待。 如果有子节点，则表示有等待发生  
select lpad(‘ ‘, decode(l.xidusn, 0, 3, 0)) || l.oracle_username user_name,
       o.owner,
       o.object_name,
       o.object_type,
       s.sid,
       s.serial#
from v$locked_object l,
     dba_objects o,
     v$session s
where l.object_id = o.object_id
  and l.session_id = s.sid
order by o.object_id, xidusn desc;


--3.找到自己用的表，记录下那个sid,serial，然后用以下语句解锁
--找到引起等待的session,杀掉该session: 
alter system kill session ‘sid,serial‘;