1.查询哪个用户致使死锁的产生：
select username,lockwait,status,machine,program from v$session where sid in
     (select session_id from v$locked_object);


2.查看当前系统锁情况
SELECT /*+ rule */
 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;




查看被死锁的语句
select sql_text from v$sql where hash_value in
    (select sql_hash_value from v$session where sid in (select session_id from v$locked_object));




3．查找被死锁的进程
SELECT s.username,l.OBJECT_ID,l.SESSION_ID,s.SERIAL#, l.ORACLE_USERNAME,
     l.OS_USER_NAME,l.PROCESS FROM V$LOCKED_OBJECT l,V$SESSION S
     WHERE l.SESSION_ID=S.SID;




4.解锁，将死锁进程kill掉
alter system kill session ‘sid,serial#’;