Oracle是一种广泛使用的关系型数据库管理系统。然而在使用Oracle时常常会遇到各种问题,其中之一就是12541无监听程序错误。当用户尝试连接数据库时,系统会提示Listener failed to start (12541)错误消息,这意味着Oracle无法找到可用的监听程序。
那么,Oracle的12541无监听程序错误该如何解决呢?下面我们将介绍几种常见的解决方法。
检查监听程序配置
首先需要确认Oracle的监听程序是否已正确配置。可以在Shell中使用lsnrctl status命令检查监听程序的状态和端口是否正确设置:
$ lsnrctl status
LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 09-MAI-2018 13:06:40
Copyright (c) 1991, 2009, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1521)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 11.2.0.1.0 - Production
Start Date 09-MAI-2018 13:04:48
Uptime 0 days 0 hr. 1 min. 52 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /opt/oracle/11.2/network/admin/listener.ora
Listener Log File /opt/oracle/diag/tnslsnr/orchard/listener/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.56.1)(PORT=1521)))
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...
The command completed successfully.
如果监听程序未启动,可以使用lsnrctl start命令手动启动。如果监听程序运行正常但未能连接到数据库,可能需要检查listener.ora配置文件。可以在listener.ora文件中设置监听程序的服务名称、端口和IP地址。如下是一个典型的listener.ora文件的示例:
# listener.ora Network Configuration File: /opt/oracle/11.2/network/admin/listener.ora
# Generated by Oracle configuration tools.
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.56.1)(PORT = 1521))
)
)
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = /opt/oracle/11.2)
(PROGRAM = extproc)
(ENVS = "LD_LIBRARY_PATH=/opt/oracle/11.2/lib:/lib:/usr/lib")
)
(SID_DESC =
(SID_NAME = ORCL)
(ORACLE_HOME = /opt/oracle/11.2)
(GLOBAL_DBNAME = orcl)
(SID_DESC =
(GLOBAL_DBNAME = orclcdb)
(ORACLE_HOME = /opt/oracle/11.2)
(SID_NAME = orclcdb)
)
)
)
检查Oracle进程
如果监听程序已启动,但仍然无法连接到Oracle数据库,可能是因为Oracle实例未能正确启动。可以使用ps命令检查所有Oracle进程的状态:
$ ps -ef|grep oracle
oracle 3285 1 0 13:10 ? 00:00:05 /opt/oracle/11.2/bin/tnslsnr LISTENER -inherit
oracle 3308 1549 0 13:10 pts/0 00:00:00 grep --color=auto oracle
oracle 23230 1 0 12:31 ? 00:00:00 ora_pmon_ORCL
oracle 23232 1 0 12:31 ? 00:00:00 ora_vktm_ORCL
oracle 23234 1 0 12:31 ? 00:00:00 ora_gen0_ORCL
oracle 23236 1 0 12:31 ? 00:00:00 ora_diag_ORCL
oracle 23238 1 0 12:31 ? 00:00:00 ora_dbrm_ORCL
oracle 23240 1 0 12:31 ? 00:00:00 ora_dia0_ORCL
oracle 23242 1 0 12:31 ? 00:00:00 ora_mman_ORCL
oracle 23244 1 0 12:31 ? 00:00:00 ora_dbw0_ORCL
oracle 23246 1 0 12:31 ? 00:00:00 ora_lgwr_ORCL
oracle 23248 1 0 12:31 ? 00:00:00 ora_ckpt_ORCL
oracle 23250 1 0 12:31 ? 00:00:00 ora_smon_ORCL
oracle 23252 1 0 12:31 ? 00:00:00 ora_reco_ORCL
oracle 23254 1 0 12:31 ? 00:00:00 ora_mmon_ORCL
oracle 23256 1 0 12:31 ? 00:00:00 ora_mmnl_ORCL
oracle 23258 1 0 12:31 ? 00:00:00 ora_d000_ORCL
oracle 23260 1 0 12:31 ? 00:00:00 ora_s000_ORCL
如果Oracle实例未能正常启动,可以使用sqlplus命令连接到系统模式并执行startup命令启动实例。
检查防火墙设置
如果Oracle已正常启动但仍无法连接到数据库,可能是因为防火墙未正确设置。需要检查Oracle所使用的端口是否已经添加到防火墙规则中。要允许来自外部的访问,可以使用iptables命令添加规则:
iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 1521 -j ACCEPT
上述命令将对外部访问1521端口的连接进行放行。
总结
在使用Oracle时,12541无监听程序错误是一个常见的问题。需要确认监听程序已正常启动,并且Oracle实例已启动。同时要注意检查防火墙设置,确保允许外部连接。通过以上方法,通常可以轻松解决12541无监听程序错误,使用户顺利地连接到Oracle数据库。