:: 极限 Linux ::Oracle HowTo:如何快速杀死占用过多资源(CPU,内存)的数据库进程

很多时候由于异常或程序错误会导致个别进程占用大量系统资源，需要结束这些进程，通常可以使用以下命令Kill进程:

alter system kill session 'sid,serial#';

但是此命令释放资源极为缓慢，具体可以参考:Oracle中Kill session的研究.
为了更快速的释放资源，通常我们使用如下步骤来Kill进程:
1.首先在操作系统级kill进程
2.在数据库内部kill session
这样通常可以快速中止进程，释放资源。

今天就遇到这样一个案例，其他朋友在数据库里kill session,可是长时间仍无效果:

[oracle@danaly ~]$ sqlplus "/ as sysdba"

            

            SQL*Plus: Release 10.2.0.1.0 - Production on Thu Oct 27 11:09:50 2005

            

            Copyright (c) 1982, 2005, Oracle.  All rights reserved.

            

            

            Connected to:

            Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production

            With the Partitioning, Oracle Label Security, OLAP and Data Mining Scoring Engine options

            

            SQL> select sid,username,status from v$session;

            

            SID USERNAME                       STATUS

            ---------- ------------------------------ --------

            ....

            154 SCOTT                          KILLED

            ...

            

            30 rows selected.

那按照我前面提到的步骤，首先查询得到该session对应的OS进程号:

SQL> select 'kill -9 '||spid from v$process where addr = (select paddr from v$session where sid=&sid);

            Enter value for sid: 154

            old   1: select 'kill -9 '||spid from v$process where addr = (select paddr from v$session where sid=&sid)

            new   1: select 'kill -9 '||spid from v$process where addr = (select paddr from v$session where sid=154)

            

            'KILL-9'||SPID

            --------------------

            kill -9 22702

            

            SQL> !

在操作系统级kill该进程:

[oracle@danaly ~]$ ps -ef|grep 22702

            oracle   22702     1  0 Oct25 ?        00:00:02 oracledanaly (LOCAL=NO)

            oracle   12082 12063  0 11:12 pts/1    00:00:00 grep 22702

            [oracle@danaly ~]$ kill -9 22702

            [oracle@danaly ~]$ ps -ef|grep 22702

            oracle   12088 12063  0 11:12 pts/1    00:00:00 grep 22702

            [oracle@danaly ~]$ exit

            exit

            

            SQL> select sid,username,status from v$session;

            

            SID USERNAME                       STATUS

            ---------- ------------------------------ --------

            ...

            154 SCOTT                          KILLED

            ...

            

            30 rows selected.

            

            SQL> select sid,serial#,username from v$session where sid=154;

            

            SID    SERIAL# USERNAME

            ---------- ---------- ------------------------------

            154      56090 SCOTT

再次在数据库中kill该session,并指定immediate选项:

SQL> alter system kill session '154,56090' immediate;

            

            System altered.

            

            SQL> select sid,serial#,username from v$session where sid=154;

            

            no rows selected

此时该进程被迅速清除。