参考文章：http://zyjustin9.iteye.com/blog/2165797

1.查看当前总会话数和进程数
    select count(*) from v$session;   
	select count(*) from v$process; 

2.查询那些应用的连接数此时是多少
    select b.MACHINE, b.PROGRAM, count(*)  
      from v$process a, v$session b  
     where a.ADDR = b.PADDR  
       and b.USERNAME is not null  
     group by b.MACHINE, b.PROGRAM  
     order by count(*) desc; 
 
3.查询是否有死锁：
    select * from v$locked_object;  

4.查找死锁
    select * from v$locked_object;  
    
5.以Oralce管理员权限用户登录Oracle数据，查询到被锁的对象
    SELECT a.object_id, a.session_id, b.object_name, c.*  
      FROM v$locked_object a, dba_objects b, v$session c  
     WHERE a.object_id = b.object_id  
       AND a.SESSION_ID = c.sid(+);  
       
6.kill session
    alter system kill session 'sid, serial#';  
    例如：查出来的一条记录的sid是149, serial#为4153,就执行以下的语句：
        alter system kill session '149,4153' ;