[20170120]db_unique_name与大小写.txt

[20170120]db_unique_name与大小写.txt

--通过例子说明:

1.环境:

SYS@book> @ &r/ver1

PORT_STRING                    VERSION        BANNER

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

x86_64/Linux 2.4.xx            11.2.0.4.0     Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production

SYS@book> alter system set db_unique_name=book ;

alter system set db_unique_name=book

                 *

ERROR at line 1:

ORA-02095: specified initialization parameter cannot be modified

--这个参数仅仅修改spfile,重启才生效.

SYS@book> show parameter db_unique_name

NAME           TYPE   VALUE

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

db_unique_name string book

--//可以发现我设置是小写,缺省你不设置好像也是小写.

2.测试:

SYS@book> alter system set db_unique_name=book scope=spfile;

System altered.

$ strings spfilebook.ora| grep -i db_unique_name=

*.db_unique_name='BOOK'

--//可以发现现在是大写.

--//要设置小写,必须这样写引号.

SYS@book> alter system set db_unique_name='book' scope=spfile;

*.db_unique_name='book'

--//取消设置.

SYS@book> alter system reset db_unique_name;

3.重启数据库:

SYS@book> shutdown immediate ;

Database closed.

Database dismounted.

ORACLE instance shut down.

SYS@book> startup

ORACLE instance started.

Total System Global Area  634732544 bytes

Fixed Size                  2255792 bytes

Variable Size             197133392 bytes

Database Buffers          427819008 bytes

Redo Buffers                7524352 bytes

Database mounted.

Database opened.

--// 设置大写.重启数据库看看.

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

db_unique_name string BOOK

--//不过一些参数并没有这个改变而发生变化:

SYS@book> show parameter dump

NAME                 TYPE    VALUE

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

background_core_dump string  partial

background_dump_dest string  /u01/app/oracle/diag/rdbms/book/book/trace

core_dump_dest       string  /u01/app/oracle/diag/rdbms/book/book/cdump

max_dump_file_size   string  unlimited

shadow_core_dump     string  partial

user_dump_dest       string  /u01/app/oracle/diag/rdbms/book/book/trace

--//我个人估计对dg应该也没有什么影响.

--//instance_name也是一样的效果,大家可以自己测试.