If the database is running, probably the database hasn’t registered yet with the listener. This occurs when the database or listener just starts up. To fix, connect as sysdba:
SHOW parameter LOCAL listener |
If something or nothing appears, reset it with:
ALTER system SET local_listener='(address=(protocol=tcp)(host=localhost)(port=1521))'; ALTER system register; |
At this point test if it’s working fine:
tnsping xe TNS Ping Utility for Linux: Version 11.2.0.2.0 - Production on 26-NOV-2012 17:04:16 Copyright (c) 1997, 2011, Oracle. All rights reserved. Used parameter files: Used TNSNAMES adapter to resolve the alias Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = 127.0.0.1)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = XE))) OK (0 msec) |