oracle listener 详解("DEDICATED" established:0 refused:0)

  http://blog.csdn.net/dream19881003/article/details/6666471

http://blog.csdn.net/tianlesoftware/article/details/6617827

最近在使用以前服务器的listner的时候，出现“不能识别当前的链接”，找了很多资料很少无奈，后来静下来想了一下客户端坚挺不到oracle，说明是服务器dispatcher的问题：

查看了一下dispatcher的参数：

 

SQL>show parameter dispachers;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
dispatchers                          string
max_dispatchers                      integer

没有内容，添加一下服务器的配置：

SQL>alter system set dispatchers='(ADDRESS=(PROTOCOL=TCP)(HOST=NAME)(PORT=port)) scope=spile;

system altered.

可以查看一下我们修改的配置：

SQL> select name,network,paddr,status from v$dispatcher;

NAME                                                                            
----                                                                            
NETWORK                                                                         
--------------------------------------------------------------------------------
PADDR    STATUS                                                                 
-------- ----------------                                                       
D000                                                                            
(ADDRESS=(PROTOCOL=tcp)(HOST=gyc)(PORT=37090))                                  
2C21A6EC WAIT 

另外一个原因是监听不是本地的默认LISTENER监听修改成本地的监听。 

SQL>alter system set local_listener='local_listener';

查看一下本地的监听：

SQL> show parameter local_listener;

NAME                                 TYPE        VALUE                          
------------------------------------ ----------- ------------------------------ 
local_listener                       string      (ADDRESS=(PROTOCOL=TCP)(HOST=g 
                                                 yc)(PORT=1522))   

 

 静态监听和动态监听：

[oracle@gyc ~]$ lsnrctl status

LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 04-AUG-2011 22:07:39

Copyright (c) 1991, 2005, Oracle.  All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=gyc)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 10.2.0.1.0 - Production
Start Date                04-AUG-2011 20:48:53
Uptime                    0 days 1 hr. 18 min. 46 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /opt/oracle/product/10.2.0/db_1/network/admin/listener.ora
Listener Log File         /opt/oracle/product/10.2.0/db_1/network/log/listener.log
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=gyc)(PORT=1521)))
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

 

静态监听显示的是“uknow“ ，动态的显示的ready如下所示：

[oracle@gyc ~]$ lsnrctl status listener1

LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 04-AUG-2011 22:08:31

Copyright (c) 1991, 2005, Oracle.  All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=gyc)(PORT=1522)))
STATUS of the LISTENER
------------------------
Alias                     listener1
Version                   TNSLSNR for Linux: Version 10.2.0.1.0 - Production
Start Date                04-AUG-2011 20:59:02
Uptime                    0 days 1 hr. 9 min. 28 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /opt/oracle/product/10.2.0/db_1/network/admin/listener.ora
Listener Log File         /opt/oracle/product/10.2.0/db_1/network/log/listener1.log
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=gyc)(PORT=1522)))
Services Summary...
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

 

静态监听的listener.ora的内容如下：

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = /opt/oracle/product/10.2.0/db_1)
      (PROGRAM = extproc)
    )
    (SID_DESC =
      (GLOBAL_DBNAME = orcl)
      (ORACLE_HOME = /opt/oracle/product/10.2.0/db_1)
      (SID_NAME = orcl)
    )
  )

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

 

动态的如下：

LISTENER1 =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = gyc)(PORT = 1522))
  )

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = /opt/oracle/product/10.2.0/db_1)
      (PROGRAM = extproc)
    )
    (SID_DESC =
      (GLOBAL_DBNAME = orcl)
      (ORACLE_HOME = /opt/oracle/product/10.2.0/db_1)
      (SID_NAME = orcl)
    )
  )

 

关于service

[oracle@gyc ~]$ lsnrctl service

LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 04-AUG-2011 22:09:44

Copyright (c) 1991, 2005, Oracle.  All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=gyc)(PORT=1521)))
Services Summary...
Service "PLSExtProc" has 1 instance(s).
  Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0
         LOCAL SERVER
Service "orcl" has 1 instance(s).
  Instance "orcl", status UNKNOWN, has 1 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0
         LOCAL SERVER
The command completed successfully

 

上面显示的是两个静态链接，服务名是orcl,实例名也是orcl， 显示的是静态监听；

   "DEDICATED" established:0 refused:0
         LOCAL SERVER
The command completed successfully

表示专有链接：链接为0，拒绝为0

 

专有链接：

每一个连接到数据库服务器的客户端请求，服务器会和客户端之间建立起连接，这个连接用于专门处理该客户端的所有请求，直到用户主动断开连接或网络出现中断。在连接处于空闲时，后台进程PMON会每隔一段时间，就会测试用户连接状况，如果连接已断开，PMON会清理现场，释放相关的资源。 专用连接相当于一对一的连接，能够快速的响应用户的请求。当然，在连接的时候，首先要创建PGA（Program global area）。

共享链接：

采用共享连接可以有效的提高服务器资源的利用率，但是对一个分配器，只支持一种协议，每个分配器有自已的排队队列，在请求的任务完成后，由分配器将操作结果返回给相应的用户进程。但是共享连接的建立， 需要Oracle的监听进程、分配器、共享服务器进程才能共同完成一个连接的创建，所以连接的分配也需要一定的时间和资源。

如何选择这两种连接方式：

在理想的情况下，对于长事务或大事务，使用专用连接，可以有效的提高系统的性能，减少用户等待和事务的排队，提高系统的利用率。对于超短事务和短事务、小事务，使用共享连接方式，可以在资源与效率之间达到一种平稀。比如对于OLTP 系统，使用专用连接，而对于网站等，可以使用共享连接。