I know that this is a pretty popular problem, and I had run into it several times before but were able to resolve it but not this time.
I had made sure that I'm using the correct service name by running
SQL> select value from v$parameter where name='service_names';
VALUE
--------------------------------------------------------------------------------
XE
My tnsnames.ora has the XE service name:
XE =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 127.0.0.1)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = XE)
)
)
When I start the listener, it appear to recognize the service: [root@aa-axm admin]# lsnrctl start
LSNRCTL for Linux: Version 11.2.0.2.0 - Production on 09-OCT-2015 12:58:28
Copyright (c) 1991, 2011, Oracle. All rights reserved.
Starting /u01/app/oracle/product/11.2.0/xe/bin/tnslsnr: please wait...
TNSLSNR for Linux: Version 11.2.0.2.0 - Production
System parameter file is /u01/app/oracle/product/11.2.0/xe/network/admin/listener.ora
Log messages written to /u01/app/oracle/product/11.2.0/xe/log/diag/tnslsnr/aa-axm/listener/alert/log.xml
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC_FOR_XE)) (SERVICE_NAME=XE))
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=127.0.0.1)(PORT=1521))(SERVICE_NAME=XE))
Connecting to (DESCRIPTION=(SERVICE_NAME=XE)(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC_FOR_XE)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 11.2.0.2.0 - Production
Start Date 09-OCT-2015 12:58:28
Uptime 0 days 0 hr. 0 min. 0 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Default Service XE
Listener Parameter File /u01/app/oracle/product/11.2.0/xe/network/admin/listener.ora
Listener Log File /u01/app/oracle/product/11.2.0/xe/log/diag/tnslsnr/aa-axm/listener/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC_FOR_XE))(SERVICE_NAME=XE))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=127.0.0.1)(PORT=1521))(SERVICE_NAME=XE))
Services Summary...
Service "PLSExtProc" has 1 instance(s).
Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service...
The command completed successfully
And yet, I'm still getting that blasted error
[root@aa-axm admin]# sqlplus SYSTEM/**********@XE
SQL*Plus: Release 11.2.0.2.0 Production on Fri Oct 9 12:58:36 2015
Copyright (c) 1982, 2011, Oracle. All rights reserved.
ERROR:
ORA-12514: TNS:listener does not currently know of service requested in connect descriptor
What am I missing? TIA