You encounter below error while connecting to Oracle DB instance, which was working before ————————— ODBC 32Bit Test Program ————————— SQLSTATE: S1000 Native Error Code:12514 Driver Message:[Oracle][ODBC][Ora]ORA-12514: TNS:listener could not resolve SERVICE_NAME given in connect descriptor Need Any suggestions to avoid error ? ————————— Yes No —————————   Troubleshooting: TNS Listener shows its status as running: [root@ProdDB01 ~]# lsnrctl status LSNRCTL for Linux: Version 8.1.6.0.0 – Production on 20-MAR-2014 10:48:58 (c) Copyright 1998, 1999, Oracle Corporation.  All rights reserved. Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=172.21.201.217)(PORT=1521))) STATUS of the LISTENER ———————— Alias                     LISTENER Version                   TNSLSNR for Linux: Version 8.1.6.0.0 – Production Start Date                20-MAR-2014 […]

Oracle Uses TNS Listener for handling the client connections and then Oracle DB service to handle the DB files   Oracle TNS Listener Log file location can be found from below:   [root@ProdDB01 ~]# lsnrctl status LSNRCTL for Linux: Version 8.1.6.0.0 – Production on 20-MAR-2014 10:48:58 (c) Copyright 1998, 1999, Oracle Corporation.  All rights reserved. Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=172.21.201.217)(PORT=1521))) STATUS of the LISTENER ———————— Alias                     LISTENER Version                   TNSLSNR for Linux: Version 8.1.6.0.0 – Production Start Date                20-MAR-2014 10:45:55 Uptime                    0 days 0 hr. 3 min. 3 sec Trace Level               off Security                  OFF SNMP                      OFF Listener Parameter File   /opt/oracle/product/8.1.6/network/admin/listener.ora Listener Log File         […]

You encounter ORA-01031: insufficient privileges error:   [root@ProdDB01 ~]# dbstart SQL*Plus: Release 8.1.6.0.0 – Production on Thu Mar 20 11:54:55 2014 (c) Copyright 1999 Oracle Corporation.  All rights reserved. SQL> ERROR: ORA-01031: insufficient privileges SQL> [3]+  Stopped                 dbstart [root@ProdDB01 ~]#   Fix: Login as Oracle user or SysDBA.  Usually, many of the administrators mayn’t have sysdba password. The workaround is to do sudo as Oracle user and start the database.   [root@ProdDB01 ~]# su – oracle -bash-3.1$ lsnrctl start LSNRCTL for Linux: Version 8.1.6.0.0 – Production on 20-MAR-2014 12:12:07 (c) Copyright 1998, 1999, Oracle Corporation.  All rights reserved. TNS-01106: Listener […]