一般是由于表挂起造成的

---查询是否有挂起的表

SELECT object_name, machine, s.sid, s.serial# FROM gv$locked_object l, dba_objects o, gv$session s WHERE l.object_id　= o.object_id AND l.session_id = s.sid;

---杀死挂起表id

ALTER system kill session '501,5234';