local_listener与remote_listener详述

简述一下local_listener与remote_listener这两个参数的含义（针对环境）

    在完RAC以后，会自动修改local_listener和remote_listener这两个参数，同时把两个节点的3要素添加到$ORACLE_HOME/network/admin下的tnsnames.ora文件中：
1.查看listeners_devdb服务名配置
[oracle@rac21admin]$ more tnsnames.ora
LISTENERS_DEVDB =
  (ADDRESS_LIST =
    (ADDRESS = (PROTOCOL = TCP)(HOST = rac1-vip)(PORT = 1521))
    (ADDRESS = (PROTOCOL = TCP)(HOST = rac2-vip)(PORT = 1521))
  )
2.show parameter local_listener and remote_listener
[oracle@rac1 admin]$ sqlplus /nolog
SQL> connsys/oracle@devdb1as sysdba
Connected.
SQL> show parameter listener
NAME                                       TYPE     VALUE
------------------------------------ ----------- ------------------------------
local_listener                        string     (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.230.68)(PORT = 1521))
remote_listener                    string     LISTENERS_DEVDB
SQL> connsys/oracle@devdb2as sysdba
Connected.
SQL> show parameter listener
NAME                                      TYPE      VALUE
------------------------------------ ----------- ------------------------------
local_listener                        string      (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.230.69)(PORT = 1521))
remote_listener                    string      LISTENERS_DEVDB
3.查看listener状态
节点1
[oracle@rac1 admin]$lsnrctl status
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
STATUS of the LISTENER
------------------------
Alias                     LISTENER_RAC1
Version                   TNSLSNR for Linux: Version 10.2.0.4.0 - Production
Start Date                28-APR-2009 10:36:56
Uptime                    0 days 8 hr. 1 min. 20 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /u01/app/oracle/product/10.2.0/db_1/network/admin/listener.ora
Listener Log File         /u01/app/oracle/product/10.2.0/db_1/network/log/listener_rac1.log
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.230.68)(PORT=1521)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=127.0.0.1)(PORT=1521)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC)))
Services Summary...
Service "devdb" has 2 instance(s).
 Instance "devdb1", status READY, has 2 handler(s) for this service...
  Instance "devdb2", status READY, has 1 handler(s) for this service...
The command completed successfully
[oracle@rac1 admin]$lsnrctl service
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
Services Summary...
Service "devdb" has 2 instance(s).
  Instance "devdb1", status READY, has 2 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:1 refused:0 state:ready
        LOCAL SERVER    --local_listener参数
      "DEDICATED" established:0 refused:0 state:ready
        REMOTE SERVER   --remote_listener参数
         (ADDRESS=(PROTOCOL=TCP)(HOST=192.168.230.68)(PORT=1521))
  Instance "devdb2", status READY, has 1 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0 state:ready
        REMOTE SERVER    --remote_listener参数
         (ADDRESS=(PROTOCOL=TCP)(HOST=192.168.230.69)(PORT=1521))
The command completed successfully
节点2
[oracle@rac2 admin]$lsnrctl status
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
STATUS of the LISTENER
------------------------
Alias                     LISTENER_RAC2
Version                   TNSLSNR for Linux: Version 10.2.0.4.0 - Production
Start Date                28-APR-2009 15:25:45
Uptime                    0 days 3 hr. 18 min. 21 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /u01/app/oracle/product/10.2.0/db_1/network/admin/listener.ora
Listener Log File         /u01/app/oracle/product/10.2.0/db_1/network/log/listener_rac2.log
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.230.69)(PORT=1521)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.230.67)(PORT=1521)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC)))
Services Summary...
Service "devdb" has 2 instance(s).
  Instance "devdb1", status READY, has 1 handler(s) for this service...
  Instance "devdb2", status READY, has 2 handler(s) for this service...
The command completed successfully
[oracle@rac2 admin]$lsnrctl service
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
Services Summary...
Service "devdb" has 2 instance(s).
  Instance "devdb1", status READY, has 1 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0 state:ready
        REMOTE SERVER    --remote_listener参数
         (ADDRESS=(PROTOCOL=TCP)(HOST=192.168.230.68)(PORT=1521))
  Instance "devdb2", status READY, has 2 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0 state:ready
        REMOTE SERVER    --remote_listener参数
         (ADDRESS=(PROTOCOL=TCP)(HOST=192.168.230.69)(PORT=1521))
      "DEDICATED" established:1 refused:0 state:ready
        LOCAL SERVER       --local_listener参数
The command completed successfully

过程描述：
        当客户端发出连接请求给端listener的时候，通过local_listener注册的服务接收这个连接请求，然后由master instance来决定这个连接请求应该由哪个目标instance发出server process响应这个连接请求。如果启用负载均衡，那么主节点会选择cpu负载最小的那个instance，此时
      如果master分配的目标instance是local listener machine，那么直接通过local server listener，开启后台的server process，处理发出conn的客户端，建立连接，处理会话;
      如果master分配的目标instance不是local listener machine，那么会通过remote_listener这个参数，把连接请求转移到remote machine上的listener, 然后由remote service listener发出一个server process返回客户端，建立连接，处理会话.
      当conn建立连接以后，listener就没有用了，不会再用到了，如果这个时候，已经连接的那个instance down了，会重新由新分配的master instance通过remote_listener切换到可用instance，此时客户不会发现连接中断。conn 和 select操作是不会中断的。
     
备注：shut down instance2，重启listener，监听服务状态
[oracle@rac2 admin]$ sqlplus /nolog
SQL> connsys/oracle@devdb2as sysdba
Connected.
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> exit
[oracle@rac2 admin]$lsnrctl status
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
STATUS of the LISTENER
------------------------
Alias                     LISTENER_RAC2
Version                   TNSLSNR for Linux: Version 10.2.0.4.0 - Production
Start Date                28-APR-2009 15:25:45
Uptime                    0 days 3 hr. 43 min. 44 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /u01/app/oracle/product/10.2.0/db_1/network/admin/listener.ora
Listener Log File         /u01/app/oracle/product/10.2.0/db_1/network/log/listener_rac2.log
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.230.69)(PORT=1521)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.230.67)(PORT=1521)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC)))
Services Summary...
Service "devdb" has 1 instance(s).
  Instance "devdb1", status READY, has 1 handler(s) for this service...
The command completed successfully
[oracle@rac2 admin]$lsnrctl service
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
Services Summary...
Service "devdb" has 1 instance(s).
  Instance "devdb1", status READY, has 1 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0 state:ready
         REMOTE SERVER
         (ADDRESS=(PROTOCOL=TCP)(HOST=192.168.230.68)(PORT=1521))
The command completed successfully
[oracle@rac2 admin]$lsnrctl stop
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
The command completed successfully
[oracle@rac2 admin]$lsnrctl start
Starting /u01/app/oracle/product/10.2.0/db_1/bin/tnslsnr: please wait...
TNSLSNR for Linux: Version 10.2.0.4.0 - Production
System parameter file is /u01/app/oracle/product/10.2.0/db_1/network/admin/listener.ora
Log messages written to /u01/app/oracle/product/10.2.0/db_1/network/log/listener.log
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=rac2.domain.com)(PORT=1521)))
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 10.2.0.4.0 - Production
Start Date                28-APR-2009 19:11:08
Uptime                    0 days 0 hr. 0 min. 0 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /u01/app/oracle/product/10.2.0/db_1/network/admin/listener.ora
Listener Log File         /u01/app/oracle/product/10.2.0/db_1/network/log/listener.log
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=rac2.domain.com)(PORT=1521)))
The listener supports no services
The command completed successfully
[oracle@rac2 admin]$lsnrctl status
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 10.2.0.4.0 - Production
Start Date                28-APR-2009 19:11:08
Uptime                    0 days 0 hr. 3 min. 28 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /u01/app/oracle/product/10.2.0/db_1/network/admin/listener.ora
Listener Log File         /u01/app/oracle/product/10.2.0/db_1/network/log/listener.log
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=rac2.domain.com)(PORT=1521)))
Services Summary...
Service "devdb" has 1 instance(s).
  Instance "devdb1", status READY, has 1 handler(s) for this service...
The command completed successfully
[oracle@rac2 admin]$lsnrctl service
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
Services Summary...
Service "devdb" has 1 instance(s).
  Instance "devdb1", status READY, has 1 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0 state:ready
         REMOTE SERVER
         (ADDRESS=(PROTOCOL=TCP)(HOST=192.168.230.68)(PORT=1521))
The command completed successfully
    此时可以看出，即使关闭实例2了，重启listener，但是实例2的service devdb 仍然可用，所以由此可以看出：
    当实例1注册监听的时候，即使节点2的instance没有启动，也会通过remote_listener在节点2server上注册相应的listener1.它是在启动的时候，添加到相应的listener service里的。

参考文献：原创
listener的静态注册与动态注册详述http://space.itpub.net/9252210/viewspace-580699

itpub oracle dba培训课程笔记(三) http://space.itpub.net/9252210/viewspace-578120

安装完RAC以后dba需要2点手工操作http://space.itpub.net/9252210/viewspace-573149