kill session 是DBA经常碰到的事情之一。如果kill 掉了不该kill 的session，则具有破坏性，因此尽可能的避免这样的错误发生。同时也应当注意，
如果kill 的session属于oracle 后台进程，则容易导致数据库实例宕机。
通常情况下，并不需要从操作系统级别杀掉Oracle会话进程，但并非总是如此，下面的描述中给出了在Oracle级别杀掉会话以及操作系统级别杀掉进程。
一、获得需要kill session的信息(使用V$SESSION 和 GV$SESSION视图)
SET LINESIZE 180
COLUMN spid FORMAT A10
COLUMN username FORMAT A10
COLUMN program FORMAT A40
SELECT s.inst_id,
s.sid,
s.serial#,
p.spid,
s.username,
s.program,
s.paddr,
s.STATUS
FROM gv$session s
JOIN gv$process p ON p.addr = s.paddr AND p.inst_id = s.inst_id
WHERE s.type != 'BACKGROUND';
INST_ID SID SERIAL# SPID USERNAME PROGRAM PADDR STATUS
---------- ---------- ---------- ---------- ---------- --------------------------------------------- -------- --------
1 146 23 27573 TEST sqlplus@oracle10g (TNS V1-V3) 4C621950 INACTIVE
1 160 17 27610 SYS sqlplus@oracle10g (TNS V1-V3) 4C624174 ACTIVE
1 144 42 27641 SCOTT sqlplus@oracle10g (TNS V1-V3) 4C624730 INACTIVE
二、使用ALTER SYSTEM KILL SESSION 命令实现
语法：
SQL> ALTER SYSTEM KILL SESSION 'sid,serial#';
SQL> ALTER SYSTEM KILL SESSION 'sid,serial#' IMMEDIATE;
SQL Language Reference
里对Immediate的解释是：IMMEDIATE Specify IMMEDIATE to instruct Oracle
Database to roll back ongoing transactions, release all session locks, recover the entire session state,
and return control to you immediately.
文章最后有oracle官方文档给出的杀进程文档详细解释
对于RAC环境下的kill session ,需要搞清楚需要kill 的session 位于哪个节点，可以查询GV$SESSION视图获得。
kill session 的时候仅仅是将会话杀掉。在有些时候，由于较大的事务或需要运行较长的SQL语句将导致需要kill的session并不能立即杀掉。对于这种情
况将收到 "marked for kill"提示(如下)，一旦会话当前事务或操作完成，该会话被立即杀掉。
alter system kill session '4730,39171'
*
ERROR at line 1:
ORA-00031: session marked for kill
在下面的操作中将杀掉会话146，144
sys@AUSTIN> alter system kill session '146,23';
System altered.
sys@AUSTIN> alter system kill session '144,42';
System altered.
sys@AUSTIN> select inst_id,saddr,sid,serial#,paddr,username,status,program from gv$session where username is not null;
INST_ID SADDR SID SERIAL# PADDR USERNAME STATUS PROGRAM
---------- -------- ---------- ---------- -------- ---------- -------- ---------------------------------------------
1 4C70BF04 144 42 4C6545A0 SCOTT KILLED sqlplus@oracle10g (TNS V1-V3)
1 4C70E6B4 146 23 4C6545A0 TEST KILLED sqlplus@oracle10g (TNS V1-V3)
1 4C71FC84 160 17 4C624174 SYS ACTIVE sqlplus@oracle10g (TNS V1-V3)
注意：在查询中可以看到被杀掉的会话的PADDR地址发生了变化，参照查询结果中的红色字体。如果多个session被kill 掉，则多个session的PADDR
被改为相同的进程地址。
通过下面的语句来找回被kill 掉的ADDR先前的地址
SELECT s.username,s.status,
x.ADDR,x.KSLLAPSC,x.KSLLAPSN,x.KSLLASPO,x.KSLLID1R,x.KSLLRTYP,
decode(bitand (x.ksuprflg,2),0,null,1)
FROM x$ksupr x,v$session s
WHERE s.paddr(+)=x.addr
and bitand(ksspaflg,1)!=0;
USERNAME STATUS ADDR KSLLAPSC KSLLAPSN KSLLASPO KSLLID1R KS D
---------- -------- -------- ---------- ---------- ------------ ---------- -- -
ACTIVE 4C623BB8 99 4 27468 275 EV 1
ACTIVE 4C623040 9 24 27444 0 1
ACTIVE 4C622A84 101 4 27480 274 EV 1
ACTIVE 4C6224C8 1 48 27450 0 1
ACTIVE 4C621F0C 1 48 27450 0 1
ACTIVE 4C6235FC 2 4 27468 0 1
SYS ACTIVE 4C624174 2 15 27442 0
ACTIVE 4C62081C 1 48 27440 0 1
ACTIVE 4C621394 1 48 27440 0 1
ACTIVE 4C620DD8 11 24 27476 0 1
ACTIVE 4C61F6E8 15 4 27610 0 1
ACTIVE 4C620260 222 24 27450 0 1
ACTIVE 4C61FCA4 7 25 27573 0 1
ACTIVE 4C61F12C 6 25 27573 0 1
ACTIVE 4C61EB70 4 24 27458 0 1
ACTIVE 4C61E5B4 1 48 27440 0 1
ACTIVE 4C61DFF8 2 24 27444 0 1
4C624730 0 0 0
4C621950 0 0 0
4C61DA3C 0 0 0
或者根据下面的语句来获得发生变化的addr
sys@AUSTIN> select p.addr from v$process p where pid <> 1
2 minus
3 select s.paddr from v$session s;
ADDR
--------
4C621950
4C624730
三、在操作系统级别杀掉会话
寻找会话对应的操作系统的进程ID
sys@AUSTIN> select SPID from v$process where ADDR in ('4C621950','4C624730') ;
SPID
----------
27573
27641
使用kill 命令来杀掉操作系统级别进程ID
kill session -9 27573
kill session -9 27641
四、获得当前会话的SID
SQL> select userenv('sid') from dual;
USERENV('SID')
--------------
627
五、多个会话需要kill 的处理办法
1.根据给定的SID(用户名)查找需要杀掉会话的信息，包括位于哪一个实例
set linesize 160
col program format a35
col username format a18
select inst_id,saddr,sid,serial#,paddr,username,status,program from gv$session
where sid in ('2731','2734','2720','2678','2685')
and username='CTICUST'
order by inst_id;
INST_ID SADDR SID SERIAL# PADDR USERNAME STATUS PROGRAM
---------- ---------------- ---------- ---------- ---------------- ------------------ -------- ---------------------------
1 00000003DAF8F870 2678 8265 00000003DBC6CA08 MSS4USR INACTIVE JDBC Thin Client
1 00000003DAF98E48 2685 83 00000003DBC08510 MSS4USR ACTIVE JDBC Thin Client
1 00000003DAFC7B80 2720 5 00000003DBBEDA20 MSS4USR INACTIVE JDBC Thin Client
1 00000003DAFD66F8 2731 3 00000003DBBE9AE0 SYS ACTIVE racgimon@svdg0028(TNS V1-V3)
1 00000003DAFDA730 2734 15 00000003DBBEC268 MSS4USR INACTIVE JDBC Thin Client
2 00000003DAFD66F8 2731 1 00000003DBBE92F8 ACTIVE oracle@svdg0029 (ARC0)
上面的查询中有一个SID为2731的位于节点2上。
也可以通过下面的方式来获得RAC的节点信息，便于确定需要kill 的session究竟位于哪一个节点。
set linesize 160
col HOST_NAME format a25
SQL> select INSTANCE_NUMBER,INSTANCE_NAME,HOST_NAME,VERSION,STATUS from gv$instance order by 1;
INSTANCE_NUMBER INSTANCE_NAME HOST_NAME VERSION STATUS
--------------- ---------------- ------------------------- ----------------- ------------
1 O02WMT1A svd0051 10.2.0.4.0 OPEN
2 O02WMT1B svd0052 10.2.0.4.0 OPEN
3 O02WMT1C svd0053 10.2.0.4.0 OPEN
2.使用下面查询来生成kill session 的语句
select 'alter system kill session '''|| sid ||',' ||SERIAL# ||''''||';' from gv$session
where sid in ('2731','2734','2720','2678','2685')
order by inst_id;
获得下列kill session的语句，根据要求由于此次需要杀掉的session全部位于节点1，因此登录到节点节点1执行下面的语句
alter system kill session '2678,8265';
alter system kill session '2685,83';
alter system kill session '2720,5';
alter system kill session '2731,3';
alter system kill session '2734,15';
alter system kill session '2731,1'; --此条命令不需要执行，该session位于节点2。
ps.
Terminating Sessions
Sometimes it is necessary to terminate current user sessions. For example, you might want to perform an administrative operation and need to terminate all non-administrative sessions. This section describes the various aspects of terminating sessions, and contains the following topics:
When a session is terminated, any active transactions of the session are rolled back, and resources held by the session (such as locks and memory areas) are immediately released and available to other sessions.
You terminate a current session using the SQL statement ALTER SYSTEM KILL SESSION. The following statement terminates the session whose system identifier is 7 and serial number is 15:
ALTER SYSTEM KILL SESSION '7,15';
Identifying Which Session to Terminate
To identify which session to terminate, specify the session index number and serial number. To identify the system identifier (SID) and serial number of a session, query the V$SESSION dynamic performance view. For example, the following query identifies all sessions for the user jward:
SELECT SID, SERIAL#, STATUS
FROM V$SESSION
WHERE USERNAME = 'JWARD'; SID SERIAL# STATUS
----- --------- --------
7 15 ACTIVE
12 63 INACTIVE
A session is ACTIVE when it is making a SQL call to Oracle Database. A session is INACTIVE if it is not making a SQL call to the database.
See Also:
Oracle Database Reference for a description of the status values for a session
Terminating an Active Session
If a user session is processing a transaction (ACTIVE status) when you terminate the session, the transaction is rolled back and the user immediately receives the following message:
ORA-00028: your session has been killed
If, after receiving the ORA-00028 message, a user submits additional statements before reconnecting to the database, Oracle Database returns the following message:
ORA-01012: not logged on
An active session cannot be interrupted when it is performing network I/O or rolling back a transaction. Such a session cannot be terminated until the operation completes. In this case, the session holds all resources until it is terminated. Additionally, the session that issues the ALTER SYSTEM statement to terminate a session waits up to 60 seconds for the session to be terminated. If the operation that cannot be interrupted continues past one minute, the issuer of the ALTER SYSTEM statement receives a message indicating that the session has been marked to be terminated. A session marked to be terminated is indicated in V$SESSION with a status of KILLED and a server that is something other than PSEUDO.
Terminating an Inactive Session
If the session is not making a SQL call to Oracle Database (is INACTIVE) when it is terminated, the ORA-00028 message is not returned immediately. The message is not returned until the user subsequently attempts to use the terminated session.
When an inactive session has been terminated, the STATUS of the session in the V$SESSION view is KILLED. The row for the terminated session is removed from V$SESSION after the user attempts to use the session again and receives the ORA-00028 message.
In the following example, an inactive session is terminated. First, V$SESSION is queried to identify the SID and SERIAL# of the session, and then the session is terminated.
SELECT SID,SERIAL#,STATUS,SERVER
FROM V$SESSION
WHERE USERNAME = 'JWARD'; SID SERIAL# STATUS SERVER
----- -------- --------- ---------
7 15 INACTIVE DEDICATED
12 63 INACTIVE DEDICATED
2 rows selected. ALTER SYSTEM KILL SESSION '7,15';
Statement processed. SELECT SID, SERIAL#, STATUS, SERVER
FROM V$SESSION
WHERE USERNAME = 'JWARD'; SID SERIAL# STATUS SERVER
----- -------- --------- ---------
7 15 KILLED PSEUDO
12 63 INACTIVE DEDICATED
2 rows selected.
转载：http://blog.csdn.net/leshami/article/details/6439019