After having problems before the work can not connect oracle, after investigation and query data and found that actually the reason Oracle log is too large (more than listening log 4G) leads to problems LISTENER listener can not connect.
Oracle log directory:
ORACLE_BASE / diag / machine name / listener / trace directory: location listener log
position alert log: ORACLE_BASE / diag / rdbms / lowercase database SID / capital data SID / trace
Solution:
Locate the directory, delete the log files, Oracle will automatically re-created