查出所有被锁住的表
select b.owner TABLEOWNER, b.object_name TABLENAME, c.OSUSER LOCKBY,

c.USERNAME LOGINID, c.sid SID, c.SERIAL# SERIAL
from v$locked_object a,dba_objects b, v$session c 
where b.object_id = a.object_id AND a.SESSION_ID =c.sid;

通过SID, SERIAL解锁 
alter system kill session 'SID, SERIAL';