--查看会话
select user name, sid, serial# from v$session
--根据sid,serial#杀死某个会话
alter system kill session '69,11660'
通过如下sql你可以查询你的每个应用程序到底在等待什么，从而针对这些信息对数据库的性能进行调整。
==============================================================================*/
Select s.username,s.program,s.status,se.event,se.total_waits,se.total_timeouts,se.time_waited,se.average_wait from v$session s, v$session_event se Where s.sid=se.sid And se.event not like 'SQl*Net%' And s.status ='ACTIVE' And s.username is not null
/*==============================================================================
2.oracle中查询被锁的表并释放session
==============================================================================*/
SELECT A.OWNER,
A.OBJECT_NAME,
B.XIDUSN,
B.XIDSLOT,
B.XIDSQN,
B.SESSION_ID,
B.ORACLE_USERNAME,
B.OS_USER_NAME,
B.PROCESS,
B.LOCKED_MODE,
C.MACHINE,
C.STATUS,
C.SERVER,
C.SID,
C.SERIAL#,
C.PROGRAM
FROM ALL_OBJECTS A, V$LOCKED_OBJECT B, SYS.GV_$SESSION C
WHERE (A.OBJECT_ID = B.OBJECT_ID)
AND (B.PROCESS = C.PROCESS)
ORDER BY 1, 2

--释放session Sql:
alter system kill session 'sid, serial#'

alter system kill session '30, 2412';
/*==============================================================================
如：
alter system kill session '379, 21132'
alter system kill session '374, 6938'
==============================================================================*/

/*==============================================================================
3.查看占用系统io较大的session
==============================================================================*/
SELECT se.sid,
se.serial#,
pr.SPID,
se.username,
se.status,
se.terminal,
se.program,
se.MODULE,
se.sql_address,
st.event,
st.p1text,
si.physical_reads,
si.block_changes
FROM v$session se, 　v$session_wait st, v$sess_io si, v$process pr
WHERE st.sid = se.sid 　AND st.sid = si.sid
AND se.PADDR = pr.ADDR
AND se.sid > 6　AND st.wait_time = 0
AND st.event NOT LIKE '%SQL%'
ORDER BY physical_reads DESC

/*==============================================================================
4.找出耗cpu较多的session
==============================================================================*/
select a.sid,spid,status,substr(a.program,1,40) prog,a.terminal,osuser,value/60/100 value
from v$session a,v$process b,v$sesstat c
where c.statistic#=12 and c.sid=a.sid and a.paddr=b.addr order by value desc;

/*==============================================================================
5.查询session被锁的sql可以用以下语句
==============================================================================*/
select sys.v_$session.osuser,sys.v_$session.machine,v$lock.sid,
　　sys.v_$session.serial#,
　　decode(v$lock.type,
　　'MR', 'Media Recovery',
　　'RT','Redo Thread',
　　'UN','User Name',
　　'TX', 'Transaction',
　　'TM', 'DML',
　　'UL', 'PL/SQL User Lock',
　　'DX', 'Distributed Xaction',
　　'CF', 'Control File',
　　'IS', 'Instance State',
　　'FS', 'File Set',
　　'IR', 'Instance Recovery',
　　'ST', 'Disk Space Transaction',
　　'TS', 'Temp Segment',
　　'IV', 'Library Cache Invalida-tion',
　　'LS', 'Log Start or Switch',
　　'RW', 'Row Wait',
　　'SQ', 'Sequence Number',
　　'TE', 'Extend Table',
　　'TT', 'Temp Table',
　　'Unknown') LockType,
　　rtrim(object_type) || ' ' || rtrim(owner) || '.' || object_name object_name,
　　decode(lmode, 0, 'None',
　　1, 'Null',
　　2, 'Row-S',
　　3, 'Row-X',
　　4, 'Share',
　　5, 'S/Row-X',
　　6, 'Exclusive', 'Unknown') LockMode,
　　decode(request, 0, 'None',
　　1, 'Null',
　　2, 'Row-S',
　　3, 'Row-X',
　　4, 'Share',
　　5, 'S/Row-X',
　　6, 'Exclusive', 'Unknown') RequestMode,
　　ctime, block b
　　from v$lock, all_objects, sys.v_$session
　　where v$Lock.sid > 6 and sys.v_$session.sid = v$lock.sid
　　and v$lock.id1 = all_objects.object_id;
　　
/*==============================================================================
OS一级for kill 处理Oracle中杀不掉的锁
如果利用上面的命令杀死一个进程后，进程状态被置为"killed"，但是锁定的资源很长时间没有被释放，
那么可以在os一级再杀死相应
==============================================================================*/
--1 查询session被锁的sql,简要查询,得到SID
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;

--2 使用alter system kill session '24,111'; (其中24,111分别是上面查询出的sid,serial#)进行释放
alter system kill session '30, 2412'

--3 执行下面的语句获得进程（线程）号,sid为第一步查询出的sid号：
select spid, osuser, s.program
from v$session s,v$process p
where s.paddr=p.addr and s.sid=30;
/*==============================================================================
4.在OS上杀死这个进程（线程）：
1)在unix上，用root身份执行命令:
#kill -9 12345（即第3步查询出的spid）
2)在windows（unix也适用）用orakill杀死线程，orakill是oracle提供的一个可执行命令，语法为：
orakill sid thread
其中：
sid：表示要杀死的进程属于的实例名
thread：是要杀掉的线程号，即第3步查询出的spid。
例：c:>orakill orcl 12345
参考：https://www.cnblogs.com/tracy/archive/2011/08/04/2127461.html



查看处于被锁状态的表：v$locked_object dba_objects v$session all_objects v$sqlarea v$lock
转载 2016年12月26日 10:09:45
--1.查看处于被锁状态的表
SELECT a.object_id,
       a.session_id,
       b.object_name
  FROM v$locked_object a,
       dba_objects     b
 WHERE a.object_id = b.object_id

select sess.sid,
sess.serial#,
lo.oracle_username,
lo.os_user_name,
ao.object_name,
lo.locked_mode
from v$locked_object lo, dba_objects ao, v$session sess
where ao.object_id = lo.object_id
and lo.session_id = sess.sid;
--2.查出锁定object的session的信息以及被锁定的object名
SELECT l.session_id sid,
       s.serial#,
       l.locked_mode,
       l.oracle_username,
       l.os_user_name,
       s.machine,
       s.terminal,
       o.object_name,
       s.logon_time
  FROM v$locked_object l,
       all_objects     o,
       v$session       s
 WHERE l.object_id = o.object_id
   AND l.session_id = s.sid
 ORDER BY sid,
          s.serial#;
--2.1查出锁定的object的session信息（指定object_name)
SELECT l.session_id sid,
       s.serial#,
       l.locked_mode,
       l.oracle_username,
       l.os_user_name,
       s.machine,
       s.terminal,
       o.object_name,
       s.logon_time
  FROM v$locked_object l, all_objects o, v$session s
 WHERE l.object_id = o.object_id
   AND l.session_id = s.sid
   and o.object_name = 'ZZOM_SEND_EMAIL'
 ORDER BY sid, s.serial#;
--3.查出锁定表的session的sid, serial#,os_user_name, machine name, terminal和执行的语句
--比上面那段多出sql_text和action
SELECT l.session_id sid,
       s.serial#,
       l.locked_mode,
       l.oracle_username,
       s.user#,
       l.os_user_name,
       s.machine,
       s.terminal,
       a.sql_text,
       a.action
  FROM v$sqlarea       a,
       v$session       s,
       v$locked_object l
 WHERE l.session_id = s.sid
   AND s.prev_sql_addr = a.address
 ORDER BY sid,
          s.serial#;
--4.查出锁定表的sid, serial#,os_user_name, machine_name, terminal，锁的type,mode
SELECT s.sid,
       s.serial#,
       s.username,
       s.schemaname,
       s.osuser,
       s.process,
       s.machine,
       s.terminal,
       s.logon_time,
       l.type
  FROM v$session s,
       v$lock    l
 WHERE s.sid = l.sid
   AND s.username IS NOT NULL
 ORDER BY sid;

参考博客：http://blog.csdn.net/fenyu8/article/details/53883906