E:\s01\app\oracle\product\11.2.0\dbhome_1\BIN>tnsping CENORCL
TNS Ping Utility for 64-bit Windows: Version 11.2.0.1.0 - Production on 25-MAY-2015 10:26:59
Copyright (c) 1997, 2010, Oracle. All rights reserved.
Used parameter files:
e:\s01\app\oracle\product\11.2.0\dbhome_1\network\admin\sqlnet.ora
Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = W01SQL0601.p
harmatechs.com)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = cenorcl)))
OK (266310 msec)查了些資料後發現是listener.log超過4G就會出現這個問題，解決很簡單。
lsnnrctl stop
刪除listener.log
lsnrctl start
恢復正常。
