//查看被锁定表有几个
select object_name,machine,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;
 
//清除锁定251,3055为查询出来的sid,serial值
alter system kill session ‘251,3055‘;