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【Oracle】-【TWO_TASK】-TWO_TASK环境变量的作用(一)

2014-11-24 13:06:37 · 作者: · 浏览: 0
标签: Oracle TWO_TASK -TWO_TASK 环境 变量 作用
【Oracle】-【TWO_TASK】-TWO_TASK环境变量的作用
当前配置的两个连接串(一个本地 数据库，一个远程数据库)： 
[oracle@liu admin]$ more tnsnames.ora
BISAL =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = bisal)
    )
  )
TEST =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = x.x.x.x)(PORT = 1524))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = star)
    )
  )

当前TWO_TASK环境变量为空： 
[oracle@liu Desktop]$ echo $TWO_TASK

[oracle@liu Desktop]$

当未指定服务名连接数据库时，默认是bisal这个本地数据库，即由系统的ORACLE_SID指定： 
[oracle@liu Desktop]$ echo $ORACLE_SID
bisal
[oracle@liu Desktop]$ env | grep SID
ORACLE_SID=bisal
[oracle@liu Desktop]$

使用/的方式连接： 
[oracle@liu Desktop]$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.1.0 - Production on Sun Aug 11 14:38:08 2013
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, OLAP and Data Mining options

SQL> select * from global_name;
GLOBAL_NAME
--------------------------------------------------------------------------------
BISAL
SQL>

设定TWO_TASK=TESTTKT： 
[oracle@liu Desktop]$ export TWO_TASK=TESTTKT
[oracle@liu Desktop]$ echo $TWO_TASK
TESTTKT
[oracle@liu Desktop]$ 
[oracle@liu Desktop]$

使用TESTTKT的用户名登陆，但不指定服务名： 
[oracle@liu Desktop]$ sqlplus star/star
SQL*Plus: Release 10.2.0.1.0 - Production on Sun Aug 11 14:39:31 2013
Copyright (c) 1982, 2005, Oracle.  All rights reserved.
Connected to:
Oracle9i Enterprise Edition Release 9.2.0.7.0 - 64bit Production
With the Partitioning, OLAP and Oracle Data Mining options
JServer Release 9.2.0.7.0 - Production

SQL> select * from global_name;
GLOBAL_NAME
--------------------------------------------------------------------------------
ALL9IT2
SQL>

此时默认连接的就是TESTTKT这个远程库了。
此时关闭本地库bisal的监听：
LSNRCTL> stop bisal
验证监听状态： 
[oracle@liu Desktop]$ tnsping bisal
TNS Ping Utility for Linux: Version 10.2.0.1.0 - Production on 11-AUG-2013 15:06:18
Copyright (c) 1997, 2005, Oracle.  All rights reserved.
Used parameter files:
/opt/oracle/102/network/admin/sqlnet.ora
Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = bisal)))
TNS-12541: TNS:no listener

再次连接bisal库： 
[oracle@liu Desktop]$ sqlplus bisal/xxx@bisal
SQL*Plus: Release 10.2.0.1.0 - Production on Sun Aug 11 15:04:54 2013
Copyright (c) 1982, 2005, Oracle.  All rights reserved.
ERROR:
ORA-12541: TNS:no listener
Enter user-name:

打开监听，再用@bisal的方式连接bisal本地库： 
[oracle@liu Desktop]$ sqlplus bisal/xxx@bisal
SQL*Plus: Release 10.2.0.1.0 - Production on Sun Aug 11 14:40:08 2013
Copyright (c) 1982, 2005, Oracle.  All rights reserved.
Error accessing PRODUCT_USER_PROFILE
Warning:  Product user profile information not loaded!
You may need to run PUPBLD.SQL as SYSTEM
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, OLAP and Data Mining options

SQL> select * from global_name;
GLOBAL_NAME
-------------------------------------------