拨云见日 正确认识password file的作用

（假如没有口令文件，在数据库未启动之前就只能通过操作系统认证）

在我们使用Rman时，许多情况下需要在nomount,mount等状态下对数据库进行处理，因此这就要求sysdba权限如果属于本地DBA组，才可以通过操作系统认证登录。

（假如是远程sysdba登录，需要通过passwordfile认证）

1.remote_login_passwordfile = NONE

在此处我们需要停用口令文件验证，因为Oracle不允许远程SYSDBA/SYSOPER身份登录。

local:

[oracle@jumper oracle]$ sqlplus "/ as sysdba"

SQL*Plus: Release 9.2.0.3.0 - Production on Thu Apr 15 09:58:45 2004

Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.

Connected to:

Oracle9i Enterprise Edition Release 9.2.0.3.0 - Production

With the Partitioning, OLAP and Oracle Data Mining options

JServer Release 9.2.0.3.0 - Production

SQL> alter user sys identified by oracle;

User altered.

SQL> show parameter pass

NAME TYPE VALUE

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

remote_login_passwordfile string NONE

remote:

E:\Oracle\ora92\bin>sqlplus /nologSQL*Plus: Release 9.2.0.4.0 -

Production on 星期四 4月 15 09:39:22 2004Copyright (c) 1982, 2002, Oracle

Corporation. All rights reserved.SQL> connect sys/oracle@hsjf as

sysdbaERROR:ORA-01017: invalid username/password; logon denied

大家可以发现，此处是无法通过口令文件验证的。

2.remote_login_passwordfile = exclusive

SQL> alter system set remote_login_passwordfile=exclusive scope=spfile;

System altered.

SQL> startup force;

ORACLE instance started.

Total System Global Area 131142648 bytes

Fixed Size 451576 bytes

Variable Size 104857600 bytes

Database Buffers 25165824 bytes

Redo Buffers 667648 bytes

Database mounted.

Database opened.

SQL> show parameter pass

NAME TYPE VALUE

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

remote_login_passwordfile string EXCLUSIVE

SQL> alter user sys identified by oracle;

User altered.

remote:

E:\Oracle\ora92\bin>sqlplus /nologSQL*Plus: Release 9.2.0.4.0 -

Production on 星期四 4月 15 09:47:11 2004Copyright (c) 1982, 2002, Oracle

Corporation. All rights reserved.SQL> connect sys/oracle@hsjf as

sysdba已连接。SQL> show userUSER 为"SYS"SQL>

此处等同于通过口令文件验证登录。

3.继续测试

假如此时我们删除passwdfile,sysdba/sysoper将会无法认证，从而无法登录数据库。

Server:

SQL> !

[oracle@jumper oracle]$ cd $ORACLE_HOME/dbs

[oracle@jumper dbs]$ ls orapwhsjf

orapwhsjf

[oracle@jumper dbs]$ mv orapwhsjf orapwhsjf.bak

[oracle@jumper dbs]$

Remote:

E:\Oracle\ora92\bin>sqlplus /nolog

SQL*Plus: Release 9.2.0.4.0 - Production on 星期四 4月 15 09:50:14 2004

Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.

SQL> connect sys/oracle@hsjf as sysdba

ERROR:

ORA-01031: insufficient privileges

SQL>

这实际上就是无法通过口令文件验证身份

4.假如丢失了passwdfile

假如你使用passwdfile后却意外丢失，那么此时将不能启动数据库。

SQL> startup force;

ORACLE instance started.

Total System Global Area 131142648 bytes

Fixed Size 451576 bytes

Variable Size 104857600 bytes

Database Buffers 25165824 bytes

Redo Buffers 667648 bytes

ORA-01990: error opening password file '/opt/oracle/product/9.2.0/dbs/orapw'

ORA-27037: unable to obtain file status

Linux Error: 2: No such file or directory

Additional information: 3

我们可以通过orapwd重建口令文件来解决此问题

此处我们恢复口令文件就可以了

SQL> !

[oracle@jumper oracle]$ mv $ORACLE_HOME/dbs/orapwhsjf.bak orapwhsjf

[oracle@jumper oracle]$ exit

exit

SQL> alter database open;

Database altered.

SQL>

5. remote_login_passwordfile = shared

Oracle9i文档说明:

SHARED

More than one database can use a password file. However, the only user recognized by the password file is SYS.

--多个数据库可以共享一个口令文件,但是只可以识别一个用户:SYS

SQL> select * from v$pwfile_users;

USERNAME SYSDB SYSOP

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

SYS TRUE TRUE

SQL> grant sysdba to eygle;

grant sysdba to eygle

*

ERROR at line 1:

ORA-01994: GRANT failed: cannot add users to public password file

SQL> show parameter password

NAME TYPE VALUE

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

remote_login_passwordfile string SHARED

大家可以发现,此时的口令文件中是不能添加用户的。

很多人可能会问：口令文件的缺省名称是orapw,如何才能共享?

其实Oracle数据库在启动时,首先查找的是orapw的口令文件,假如该文件不存在,则开始查找,orapw的口令文件。如果口令文件命名为orapw,多个数据库就可以共享。

再来看一下测试:

[oracle@jumper dbs]$ sqlplus "/ as sysdba"

SQL*Plus: Release 9.2.0.3.0 - Production on Tue Jul 6 09:40:34 2004

Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.

Connected to:

Oracle9i Enterprise Edition Release 9.2.0.3.0 - Production

With the Partitioning, OLAP and Oracle Data Mining options

JServer Release 9.2.0.3.0 - Production

SQL> shutdown immediate

Database closed.

Database dismounted.

ORACLE instance shut down.

SQL> !

[oracle@jumper dbs]$ ls

hsjf initdw.ora inithsjf.ora init.ora lkHSJF orapwhsjf spfilehsjf.ora

[oracle@jumper dbs]$ mv orapwhsjf orapwhsjf.bak

[oracle@jumper dbs]$ exit

exit

SQL> startup

ORACLE instance started.

Total System Global Area 235999908 bytes

Fixed Size 451236 bytes

Variable Size 201326592 bytes

Database Buffers 33554432 bytes

Redo Buffers 667648 bytes

ORA-01990: error opening password file '/opt/oracle/product/9.2.0/dbs/orapw'

--它是最后查找的文件

ORA-27037: unable to obtain file status

Linux Error: 2: No such file or directory

Additional information: 3

建立orapw口令文件,此时可以打开数据库。

SQL> !

[oracle@jumper dbs]$ ls

hsjf initdw.ora inithsjf.ora init.ora lkHSJF orapwhsjf.bak spfilehsjf.ora

[oracle@jumper dbs]$ cp orapwhsjf.bak orapw

[oracle@jumper dbs]$ exit

exit

SQL> alter database open;

Database altered.

SQL> show parameter passw

NAME TYPE VALUE

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

remote_login_passwordfile string SHARED

SQL>

很多人可能会产生有这样的疑问,多个Exclusive的数据库是否可以共享一个口令文件(orapw)呢?

继续回到试验中:

SQL> show parameter passwordNAME TYPE VALUE

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

remote_login_passwordfile string SHARED

[oracle@jumper dbs]$ strings orapw

]\[Z

ORACLE Remote Password file

INTERNAL

AB27B53EDC5FEF41

8A8F025737A9097A

注意这里仅记录着INTERNAL/SYS的口令

REMOTE_LOGIN_PASSWORDFILE=EXCLUSIVE 时

SQL> alter system set remote_login_passwordfile=exclusive scope=spfile;System altered.

SQL> startup force;

ORACLE instance started.

Total System Global Area 235999908 bytes

Fixed Size 451236 bytes

Variable Size 201326592 bytes

Database Buffers 33554432 bytes

Redo Buffers 667648 bytes

Database mounted.

Database opened.

SQL> !

[oracle@jumper bin]$ cd $ORACLE_HOME/dbs

[oracle@jumper dbs]$ strings orapw

]\[Z

ORACLE Remote Password file

HSJF

INTERNAL

AB27B53EDC5FEF41

8A8F025737A9097A

[oracle@jumper dbs]$ exit

exit

注意此处,以EXCLUSIVE方式启动以后,实例名称信息就会被写入口令文件.

如果此时有其它实例以Exclusive模式启动仍然可以使用这个口令文件,口令文件中的实例名称同时被改写.

这也就是说,数据库只在启动过程中才读取口令文件,数据库运行过程中并不锁定该文件,类似于pfile/spfile文件.

SQL> select * from v$pwfile_users;USERNAME SYSDB SYSOP

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

SYS TRUE TRUE

SQL> grant sysdba to eygle;

Grant succeeded.

SQL> select * from v$pwfile_users;

USERNAME SYSDB SYSOP

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

SYS TRUE TRUE

EYGLE TRUE FALSE

SQL> !

[oracle@jumper bin]$ cd $ORACLE_HOME/dbs

[oracle@jumper dbs]$ strings orapw

]\[Z

ORACLE Remote Password file

HSJF

INTERNAL

AB27B53EDC5FEF41

8A8F025737A9097A

>EYGLE

B726E09FE21F8E83

注意：

在此处我们可以增加SYSDBA用户，并且这些信息可以被写入到口令文件。

如果我们在口令文件中增加了其他SYSDBA用户,这个文件就不能被其它Exclusive的实例共享。

仔细了解过后，我们可以发觉，口令文件对于其他用户来说其实就是启到了一个sudo的作用。

6.重建口令文件

假如口令文件丢失,使用orapwd可以很方便的重建口令文件，详细的语法如下:

[oracle@jumper oracle]$ orapwdUsage: orapwd file= password= entries= where

file - name of password file (mand),

password - password for SYS (mand),

entries - maximum number of distinct DBA and OPERs (opt),

There are no spaces around the equal-to (=) character.