oracle监听器初识-配置多SERVICE_NAMES

现象：

---

为数据库设置多个服务名（通过SCOPE=both设置，同时修改参数文件）

 SQL> show parameter service_names;

 NAME                     TYPE     VALUE
 ------------------------------------ ----------- ------------------------------
 service_names                 string     vmdb

 SQL> alter system set service_names='vmdb,sn01,sn02' scope=both;

 System altered.

重启监听后，监听状态并未显示服务sn01,sn02

 [oracle@CentOS ~]$ lsnrctl stop

 LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 26-MAR-2018 18:29:21

 Copyright (c) 1991, 2009, Oracle.  All rights reserved.

 Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=CentOS)(PORT=1521)))
 The command completed successfully
 [oracle@CentOS ~]$ lsnrctl start

 LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 26-MAR-2018 18:29:24

 Copyright (c) 1991, 2009, Oracle.  All rights reserved.

 Starting /u01/app/oracle/product/11.2.0/dbhome_1/bin/tnslsnr: please wait...

 TNSLSNR for Linux: Version 11.2.0.1.0 - Production
 System parameter file is /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
 Log messages written to /u01/app/oracle/diag/tnslsnr/CentOS/listener/alert/log.xml
 Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=CentOS)(PORT=1521)))

 Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=CentOS)(PORT=1521)))
 STATUS of the LISTENER
 ------------------------
 Alias                     LISTENER
 Version                   TNSLSNR for Linux: Version 11.2.0.1.0 - Production
 Start Date                26-MAR-2018 18:29:24
 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/11.2.0/dbhome_1/network/admin/listener.ora
 Listener Log File         /u01/app/oracle/diag/tnslsnr/CentOS/listener/alert/log.xml
 Listening Endpoints Summary...
   (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=CentOS)(PORT=1521)))
 Services Summary...
 Service "vmdb" has 1 instance(s).
   Instance "vmdb", status UNKNOWN, has 1 handler(s) for this service...
 The command completed successfully

通过另一台机器通过服务名sn01连接可以连接上：

 [oracle@centos-sample ~]$ sqlplus test/test@192.168.8.141/sn01

 SQL*Plus: Release 11.2.0.1.0 Production on Sun Mar 25 20:06:35 2018

 Copyright (c) 1982, 2009, Oracle.  All rights reserved.

 ERROR:
 ORA-28002: the password will expire within 7 days

 Connected to:
 Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
 With the Partitioning, OLAP, Data Mining and Real Application Testing options

 SQL> 

在数据库中可以查询v$session视图的service_name来判断会话是由通过哪个服务名连接创建的：

 SQL> col paddr format a20
 SQL> col Sid format 9999999
 SQL> col username format a15
 SQL> col service_name format a20
 SQL> Select paddr,Sid,serial#,username,service_name From v$session  Where username Is Not Null;

 PADDR              SID     SERIAL# USERNAME     SERVICE_NAME
 -------------------- -------- ---------- --------------- --------------------
 000000008DC95250       17          19 SYS         SYS$USERS
 000000008DC98310       36           7 TEST         vmdb
 000000008DC96290       37          22 TEST         sn01
 000000008DC99350       38          11 TEST         vmdb

重启数据库：

 SQL> shutdown immediate;
 Database closed.
 Database dismounted.
 ORACLE instance shut down.
 SQL> startup
 ORACLE instance started.

 Total System Global Area  776646656 bytes
 Fixed Size            2217384 bytes
 Variable Size          583010904 bytes
 Database Buffers      188743680 bytes
 Redo Buffers            2674688 bytes
 Database mounted.
 Database opened.

再次查看监听，sn01,sn02服务名显示出来了：

 [oracle@CentOS ~]$ lsnrctl status

 LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 26-MAR-2018 18:30:29

 Copyright (c) 1991, 2009, Oracle.  All rights reserved.

 Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=CentOS)(PORT=1521)))
 STATUS of the LISTENER
 ------------------------
 Alias                     LISTENER
 Version                   TNSLSNR for Linux: Version 11.2.0.1.0 - Production
 Start Date                26-MAR-2018 18:29:24
 Uptime                    0 days 0 hr. 1 min. 5 sec
 Trace Level               off
 Security                  ON: Local OS Authentication
 SNMP                      OFF
 Listener Parameter File   /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
 Listener Log File         /u01/app/oracle/diag/tnslsnr/CentOS/listener/alert/log.xml
 Listening Endpoints Summary...
   (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=CentOS)(PORT=1521)))
 Services Summary...
 Service "sn01" has 1 instance(s).
   Instance "vmdb", status READY, has 1 handler(s) for this service...
 Service "sn02" has 1 instance(s).
   Instance "vmdb", status READY, has 1 handler(s) for this service...
 Service "vmdb" has 2 instance(s).
   Instance "vmdb", status UNKNOWN, has 1 handler(s) for this service...
   Instance "vmdb", status READY, has 1 handler(s) for this service...
 Service "vmdbXDB" has 1 instance(s).
   Instance "vmdb", status READY, has 1 handler(s) for this service...
 The command completed successfully

但是监听配置文件里不会自动增加服务名sn01,sn02：

 [oracle@CentOS ~]$ cat /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
 # listener.ora Network Configuration File: /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
 # Generated by Oracle configuration tools.

 SID_LIST_LISTENER =
   (SID_LIST =
     (SID_DESC =
       (GLOBAL_DBNAME = vmdb)
       (ORACLE_HOME = /u01/app/oracle/product/11.2.0/dbhome_1)
       (SID_NAME = vmdb)
     )
   )

 LISTENER =
   (DESCRIPTION =
     (ADDRESS = (PROTOCOL = TCP)(HOST = CentOS)(PORT = 1521))
   )

 ADR_BASE_LISTENER = /u01/app/oracle

listener.ora文件典型配置：

---

 SID_LIST_LISTENER =
   (SID_LIST =
     (SID_DESC =
       (SID_NAME = PLSExtProc)
       (ORACLE_HOME = /u01/app/oracle/product/11.2.0/dbhome_1)
       (PROGRAM = extproc)
     )
     (SID_DESC =
       (GLOBAL_DBNAME = vmdb)
       (ORACLE_HOME = /u01/app/oracle/product/11.2.0/dbhome_1)
       (SID_NAME = vmdb)
     )
     (SID_DESC =
       (GLOBAL_DBNAME = sn01)
       (ORACLE_HOME = /u01/app/oracle/product/11.2.0/dbhome_1)
       (SID_NAME = vmdb)
     )
     (SID_DESC =
       (GLOBAL_DBNAME = sn02)
       (ORACLE_HOME = /u01/app/oracle/product/11.2.0/dbhome_1)
       (SID_NAME = vmdb)
     )
   )

 LISTENER =
   (DESCRIPTION =
     (ADDRESS = (PROTOCOL = TCP)(HOST = CentOS)(PORT = 1521))
   )

以下解释来自老盖的《深入浅出ORACLE》：

监听器文件主要包含两个部分：

• 第一部分LISTENER信息，这部分包含了监听的协议、地址以及端口等信息。
• 第二部分SID_LIST_LISTENER信息，这部分信息用于提供对外的数据库服务列表。第一个SID_DESC部分（SID_NAME = PLSExtProc）是数据库缺省就包含的对外部存储过程提供的本地监听，此外三个SID_DESC部分是对数据库的三个SERVICE_NAMES所设置的监听服务，对于同一个SID对应的数据库，可以对外提供多个服务名供客户端访问。

　　　设置服务名的参数为GLOBAL_DBNAME，当处理客户端连接请求时，监听器首先尝试将GLOBAL_DBNAME和客户端请求中的SERVICE_NAME相匹配；如果客户端连接请求的是SID信息，则Oracle不检查GLOBAL_DBNAME设置，而是对监听器中设置的SID_NAME进行匹配。

　　　启动这个监听后，可以看到对于不同服务名Oracle所启动的监听信息。首先输出的信息显示了监听器文件地址以及监听日志文件位置（监听器日志在诊断数据库异常或攻击信息时非常有用）。

　　　通过服务名，Oracle可以将客户端和服务器彻底隔离开来，对于客户端来说，它不用关心数据库的名字、实例名到底是什么，它只需要知道数据库对外提供的服务名就行了，这个名字可能和实例名相同，也可能不相同。

　　　（注：通过查询会话视图v$session的service_names，可以区分哪些会话来自哪个service_name，所以可以通过提供不同的service_name给不同的下游系统，用来区分哪些会话由哪些系统创建）

　　从8i开始，oracle引入了动态服务注册（Dynamic Service Registration）的功能，所谓动态注册是指当实例启动之后，由后台进程PMON在监听器中注册数据库服务信息。在动态注册机制下，原来监听器中的SID_LIST部分将不再需要。动态注册的服务名，由于监听器确切地知道实例的状态，所以正常状态通常显示为READY，而对于静态注册的服务名，则状态显示为UNKNOW。

　　以下演示，删除监听配置文件listener.ora后，监听器依然可以知道动态注册的服务名：

 [oracle@CentOS ~]$ cd /u01/app/oracle/product/11.2./dbhome_1/network/admin/
 [oracle@CentOS admin]$ ll
 总用量
 -rw-r--r--   oracle oinstall   3月   : listener.ora
 drwxr-xr-x.  oracle oinstall  5月     samples
 -rw-r--r--.  oracle oinstall   5月     shrept.lst
 -rw-r-----.  oracle oinstall   5月     tnsnames.ora
 [oracle@CentOS admin]$ lsnrctl stop

 LSNRCTL for Linux: Version 11.2.0.1. - Production on -MAR- ::

 Copyright (c) , , Oracle.  All rights reserved.

 Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=CentOS)(PORT=)))
 The command completed successfully

 [oracle@CentOS admin]$ ll
 总用量
 -rw-r--r--   oracle oinstall   3月   : listener.ora
 drwxr-xr-x.  oracle oinstall  5月     samples
 -rw-r--r--.  oracle oinstall   5月     shrept.lst
 -rw-r-----.  oracle oinstall   5月     tnsnames.ora
 [oracle@CentOS admin]$ mv listener.ora listener.ora_bak
 [oracle@CentOS admin]$ lsnrctl start

 LSNRCTL for Linux: Version 11.2.0.1. - Production on -MAR- ::

 Copyright (c) , , Oracle.  All rights reserved.

 Starting /u01/app/oracle/product/11.2./dbhome_1/bin/tnslsnr: please wait...

 TNSLSNR for Linux: Version 11.2.0.1. - Production
 Log messages written to /u01/app/oracle/diag/tnslsnr/CentOS/listener/alert/log.xml
 Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=CentOS)(PORT=)))

 Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=))
 STATUS of the LISTENER
 ------------------------
 Alias                     LISTENER
 Version                   TNSLSNR for Linux: Version 11.2.0.1. - Production
 Start Date                -MAR- ::
 Uptime                     days  hr.  min.  sec
 Trace Level               off
 Security                  ON: Local OS Authentication
 SNMP                      OFF
 Listener Log File         /u01/app/oracle/diag/tnslsnr/CentOS/listener/alert/log.xml
 Listening Endpoints Summary...
   (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=CentOS)(PORT=)))
 The listener supports no services
 The command completed successfully
 [oracle@CentOS admin]$ lsnrctl status

 LSNRCTL for Linux: Version 11.2.0.1. - Production on -MAR- ::

 Copyright (c) , , Oracle.  All rights reserved.

 Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=))
 STATUS of the LISTENER
 ------------------------
 Alias                     LISTENER
 Version                   TNSLSNR for Linux: Version 11.2.0.1. - Production
 Start Date                -MAR- ::
 Uptime                     days  hr.  min.  sec
 Trace Level               off
 Security                  ON: Local OS Authentication
 SNMP                      OFF
 Listener Log File         /u01/app/oracle/diag/tnslsnr/CentOS/listener/alert/log.xml
 Listening Endpoints Summary...
   (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=CentOS)(PORT=)))
 Services Summary...
 Service "sn01" has  instance(s).
   Instance "vmdb", status READY, has  handler(s) for this service...
 Service "sn02" has  instance(s).
   Instance "vmdb", status READY, has  handler(s) for this service...
 Service "vmdb" has  instance(s).
   Instance "vmdb", status READY, has  handler(s) for this service...
 Service "vmdbXDB" has  instance(s).
   Instance "vmdb", status READY, has  handler(s) for this service...
 The command completed successfully

可以看到只有动态注册的服务名，没有了UNKNOW。

启动监听时，虽然显示The listener supports no services，但是由于动态注册是PMON进程主动向监听器注册，所以监听状态依然能看到动态注册的服务处于READY状态，可以对外提供访问服务。