我们知道,在Oracle数据库中,可以通过kill session的方式来终止一个进程,其基本语法结构为:
&U/a)hR1EH0alter system kill session 'sid,serial#' ;51Testing软件测试网yc#Q;oQY
51Testing软件测试网v
Q)u;UO)K
^4F被kill掉的session,状态会被标记为killed,Oracle会在该用户下一次touch时清除该进程.51Testing软件测试网3y2@8y TNnf
我们发现当一个session被kill掉以后,该session的paddr被修改,如果有多个session被kill,那么多个session51Testing软件测试网jxx+B;|4v
的paddr都被更改为相同的进程地址:
-RZ e r'e"G|)ux051Testing软件测试网({
}q `N+BN51Testing软件测试网h)k)F1{dz 51Testing软件测试网`&wJ'f#M2an*N SQL> select saddr,sid,serial#,paddr,username,status from v$session where username is not null;
SADDR SID SERIAL# PADDR USERNAME STATUS
-------- ---------- ---------- -------- ------------------------------ --------
542E0E6C 11 314542B70E8EYGLE INACTIVE
542E5044 18 662 542B6D38 SYS ACTIVE
SQL> alter system kill session '11,314';
System altered.
SQL> select saddr,sid,serial#,paddr,username,status from v$session where username is not null;
SADDR SID SERIAL# PADDR USERNAME STATUS
-------- ---------- ---------- -------- ------------------------------ --------
542E0E6C 11 314542D6BD4EYGLE KILLED
542E5044 18 662 542B6D38 SYS ACTIVE
SQL> select saddr,sid,serial#,paddr,username,status from v$session where username is not null;
SADDR SID SERIAL# PADDR USERNAME STATUS
-------- ---------- ---------- -------- ------------------------------ --------
542E0E6C 11 314542D6BD4EYGLE KILLED
542E2AA4 14 397542B7498EQSP INACTIVE
542E5044 18 662 542B6D38 SYS ACTIVE
SQL> alter system kill session '14,397';
System altered.
SQL> select saddr,sid,serial#,paddr,username,status from v$session where username is not null;
SADDR SID SERIAL# PADDR USERNAME STATUS
-------- ---------- ---------- -------- ------------------------------ --------
542E0E6C 11 314542D6BD4EYGLE KILLED
542E2AA4 14 397542D6BD4EQSP KILLED
542E5044 18 662 542B6D38 SYS ACTIVE |
51Testing软件测试网p1O
I[0H2x6I wy在这种情况下,很多时候,资源是无法释放的,我们需要查询spid,在操作系统级来kill这些进程.
+J}5IfF}L+MBM4t0但是由于此时v$session.paddr已经改变,我们无法通过v$session和v$process关联来获得spid51Testing软件测试网S%Sz*c#rW}s
那还可以怎么办呢?51Testing软件测试网G.c8s,QpD`@(j
我们来看一下下面的查询:
4iMk o;J+n9k09_OX,v3o0
4h0m7T%L[,A^ObX0 [/]GHI0SxMvO;q:`z1t0 t]4T6_Am UJr)^/g0SQL> SELECT s.username,s.status,
2 x.ADDR,x.KSLLAPSC,x.KSLLAPSN,x.KSLLASPO,x.KSLLID1R,x.KSLLRTYP,
3 decode(bitand (x.ksuprflg,2),0,null,1)
4 FROM x$ksupr x,v$session s
5 WHERE s.paddr(+)=x.addr
6 and bitand(ksspaflg,1)!=0;
USERNAME STATUS ADDR KSLLAPSC KSLLAPSN KSLLASPO KSLLID1R KS D
------------------------------ -------- -------- ---------- ---------- ------------ ---------- -- -
542B44A8 0 0 0
ACTIVE 542B4858 1 14 24069 0 1
ACTIVE 542B4C08 26 16 15901 0 1
ACTIVE 542B4FB8 7 46 24083 0 1
ACTIVE 542B5368 12 15 24081 0 1
ACTIVE 542B5718 15 46 24083 0 1
ACTIVE 542B5AC8 79 4 15923 0 1
ACTIVE 542B5E78 50 16 24085 0 1
ACTIVE 542B6228 754 15 24081 0 1
ACTIVE 542B65D8 1 14 24069 0 1
ACTIVE 542B6988 2 30 14571 0 1
USERNAME STATUS ADDR KSLLAPSC KSLLAPSN KSLLASPO KSLLID1R KS D
------------------------------ -------- -------- ---------- ---------- ------------ ---------- -- -
SYS ACTIVE 542B6D38 2 8 24071 0542B70E8 1 15 24081 195 EV
542B7498 1 15 24081 195 EVSYS INACTIVE 542B7848 0 0 0
SYS INACTIVE 542B7BF8 1 15 24081 195 EV
16 rows selected. 51Testing软件测试网4t"@\
N?0v_ M2Sy
OO5vpq0V/o]0spJX o]0 (Gpo5E(iq0 |
c-C6SF}C051Testing软件测试网!KMwl.TyX;i我们注意,红字标出的部分就是被Kill掉的进程的进程地址.
/DMByee-E0简化一点,其实就是如下概念:
|8|8q(xu8n})i h051Testing软件测试网},Ej)Aj+CEdd7rSQL> select p.addr from v$process p where pid <> 1 /t w
H'e9vpPyx02 minus ;n4h+qEB2@03 select s.paddr from v$session s; ADDR51Testing软件测试网.m"lxly!BKC -------- IGp3}U$sZIZ0542B70E8 B:z4L*b6wv}0542B7498 1P5J1pb$X"G+_MLbh@0 EF!A9|OZv
x-A$z |0 |
51Testing软件测试网
Xa7VR&o;@nOk,现在我们获得了进程地址,就可以在v$process中找到spid,然后可以使用Kill或者orakill在系统级来杀掉这些进程.
j:k`Zl0实际上,我猜测:51Testing软件测试网6DJi'x3E.w?0p
当在Oracle中kill session以后, Oracle只是简单的把相关session的paddr 指向同一个虚拟地址.
D ^y3jO0此时v$process和v$session失去关联,进程就此中断.51Testing软件测试网.OL~1iEo6DFV
然后Oracle就等待PMON去清除这些Session.所以通常等待一个被标记为Killed的Session退出需要花费很长的时间.51Testing软件测试网.J
@0pFW f y-D7@;Z5M
如果此时被Kill的process,重新尝试执行任务,那么马上会收到进程中断的提示,process退出,此时Oracle会立即启动PMON
c;RO5Mq-I4}#TZ0来清除该session.这被作为一次异常中断处理.
GHqgm8KZz0