同时在自己电脑上装了oracle客户端和服务器,上次还能用呢,这次突然用不了. 
 
 
 [oracle@R39i oracle]$ sqlplus scott/tiger
 
 SQL*Plus: Release 9.2.0.4.0 - Production on Mon Nov 24 11:06:50 2008
 
 Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
ERROR:
ORA-01034: ORACLE not available
ORA-27101: shared memory realm does not exist
Linux Error: 2: No such file or directory
 
 [root@R39i root]# id oracle
uid=500(oracle) gid=501(dba) groups=501(dba)
[root@R39i root]# su - oracle
[oracle@R39i oracle]$ lsnrctl start
 
 LSNRCTL for Linux: Version 9.2.0.4.0 - Production on 24-NOV-2008 10:57:29
 
 Copyright (c) 1991, 2002, Oracle Corporation. All rights reserved.
 
 Starting /oracle/product/9i/bin/tnslsnr: please wait...
 
 TNSLSNR for Linux: Version 9.2.0.4.0 - Production
System parameter file is /oracle/product/9i/network/admin/listener.ora
Log messages written to /oracle/product/9i/network/log/listener.log
Error listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC)))
TNS-12542: TNS:address already in use
TNS-12560: TNS:protocol adapter error
TNS-00512: Address already in use
   Linux Error: 98: Address already in use
 
 Listener failed to start. See the error message(s) above...
 
 [oracle@R39i oracle]$ lsnrctl status
 
 LSNRCTL for Linux: Version 9.2.0.4.0 - Production on 24-NOV-2008 11:21:13
 
 Copyright (c) 1991, 2002, Oracle Corporation. All rights reserved.
 
 Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC)))
STATUS of the LISTENER
==============================================
[oracle@R39i oracle]$ lsnrctl status
 
 LSNRCTL for Linux: Version 9.2.0.4.0 - Production on 24-NOV-2008 11:21:13
 
 Copyright (c) 1991, 2002, Oracle Corporation. All rights reserved.
 
 Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 9.2.0.4.0 - Production
Start Date                24-NOV-2008 10:52:27
Uptime                    0 days 0 hr. 28 min. 45 sec
Trace Level               off
Security                  OFF
SNMP                      OFF
Listener Parameter File   /oracle/product/9i/network/admin/listener.ora
Listener Log File         /oracle/product/9i/network/log/listener.log
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=R39i)(PORT=1521)))
Services Summary...
Service "PLSExtProc" has 1 instance(s).
Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service...
Service "mydata" has 1 instance(s).
Instance "mydata", status UNKNOWN, has 1 handler(s) for this service...
The command completed successfully
 
 呵呵,原来监听已经启动了.
[oracle@R39i oracle]$ sqlplus /nolog
 
 SQL*Plus: Release 9.2.0.4.0 - Production on Mon Nov 24 12:01:37 2008
 
 Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
 
 SQL> connect /as sysdba
Connected to an idle instance.
SQL> startup
ORACLE instance started.
 
 Total System Global Area 122754448 bytes
Fixed Size                   451984 bytes
Variable Size              88080384 bytes
Database Buffers           33554432 bytes
Redo Buffers                 667648 bytes
Database mounted.
Database opened.
 
 数据库就可以用了。
 
 总结,
 
 1,数据库没有打开时,其它用户是联不上的。
2,如果用sys也打不开数据库,则可能是坏境变量的事了。
 
 可用下面的方法来检查,看是否和你预想的一样。
 
 env |grep ORACLE