一、动态监听
oracle监听器是一个独立的进程，通常在数据库实例启动前先启动，当oracle实例在open时，会动态向监听器程序注册其service_names和instance_name。实例启动的时候，PMON进程会根据instance_name,service_name参数将实例和服务动态注册到listerer中。
1. listener.ora默认配置文件
# cat /u01/app/oracle/product/10.2.0/db_1/network/admin/listener.ora
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = /u01/app/oracle/product/10.2.0/db_1)
(PROGRAM = extproc)
)
)
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = node1)(PORT = 1521))
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
)
)
2. 查看监听状态，可以通过status READY状态看到是采用的动态监听。
[oracle@node1 ~]$ lsnrctl status
LSNRCTL for Linux: Version 10.2.0.5.0 - Production on 21-11014 22:27:29
Copyright (c) 1991, 2010, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=node1)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 10.2.0.5.0 - Production
Start Date 21-11014 22:26:37
Uptime 0 days 0 hr. 0 min. 52 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=node1)(PORT=1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC0)))
Services Summary...
Service "PLSExtProc" has 1 instance(s).
Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service...
Service "orcl" has 1 instance(s).
Instance "orcl", status READY, has 1 handler(s) for this service...
Service "orclXDB" has 1 instance(s).
Instance "orcl", status READY, has 1 handler(s) for this service...
Service "orcl_XPT" has 1 instance(s).
Instance "orcl", status READY, has 1 handler(s) for this service...
The command completed successfully
[oracle@node1 ~]$
3. 监听启动与关闭
$ lsnrctl start
$ lsnrctl stop
4. 手工动态注册监听
数据库在监听器运行之后，open数据库时动态注册才会进行，如果监听器重启，动态注册信息将会暂时丢失，直到PMON进程会周期性扫描实例中service_names和instance_name后再进行动态注册。也可以手动注册，仅限于默认监听。
SQL> alter system register;
二、静态监听
静态注册就是通过实例启动时读取listener.ora文件的配置，将实例GLOBAL_DBNAME和服务注册到监听程序。无论数据库是否已启动，默认地都有两条信息注册到监听器中，可以随时保证可以远程通过监听连接到数据库。
1. listener.ora配置静态监听配置文件
# cat /u01/app/oracle/product/10.2.0/db_1/network/admin/listener.ora
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = /u01/app/oracle/product/10.2.0/db_1)
(PROGRAM = extproc)
)
(SID_DESC =
(SID_NAME = orcl)
(ORACLE_HOME = /u01/app/oracle/product/10.2.0/db_1)
(SID_NAME = orcl)
)
)
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = node1)(PORT = 1521))
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
)
)
2. 查看监听状态，可以通过status UNKNOWN状态看到是采用的动态监听。
[oracle@node1 admin]$ lsnrctl status
LSNRCTL for Linux: Version 10.2.0.5.0 - Production on 21-11014 22:58:16
Copyright (c) 1991, 2010, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=node1)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 10.2.0.5.0 - Production
Start Date 21-11014 22:58:04
Uptime 0 days 0 hr. 0 min. 11 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=node1)(PORT=1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC0)))
Services Summary...
Service "PLSExtProc" has 1 instance(s).
Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service...
Service "orcl" has 1 instance(s).
Instance "orcl", status UNKNOWN, has 1 handler(s) for this service...
The command completed successfully
[oracle@node1 admin]$
3. 如果在实际环境中在客户端访问数据库时出现如下错误提示，可以采用静态监听的方式去解决。
ORA-12514: TNS :监听程序当前无法识别连接描述符中请求的服务_监听程序不支持服务
三、监听中配置（IP=FIRST）参数作用
1，在没有配置IP=FIRST之前服务器监听器会在本机所有IP地址1521端口上进行监听，如果本机上有多个IP地址，可以访问。
[root@node1 ~]# netstat -tunlp |grep 1521
tcp 0 0 0.0.0.0:1521 0.0.0.0:* LISTEN 4071/tnslsnr
2. 配置（IP=FIRST）
$ cat /u01/app/oracle/product/10.2.0/db_1/network/admin/listener.ora
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = /u01/app/oracle/product/10.2.0/db_1)
(PROGRAM = extproc)
)
(SID_DESC =
(SID_NAME = orcl)
(ORACLE_HOME = /u01/app/oracle/product/10.2.0/db_1)
(SID_NAME = orcl)
)
)
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = node1)(PORT = 1521)(IP=FIRST))
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
)
)
3. 重启监听后的效果，本机主机名配置在127.0.0.1上，监听应该在127.0.0.1上, 也可以指定本机上一个IP地址做为监听地址，这里仅是示例。
$ cat /etc/hosts
127.0.0.1 node1 localhost.localdomain localhost
$ lsnrctl stop
$ lsnrctl start
$ netstat -tunlp |grep 1521
tcp 0 0 127.0.0.1:1521 0.0.0.0:* LISTEN 4157/tnslsnr
本文转自 koumm 51CTO博客，原文链接：http://blog.51cto.com/koumm/1581139，如需转载请自行联系原作者
