hello:

the nxlog  DEBUG  log  are:

section 1

2017-04-24 16:15:40 DEBUG check file: /u01/app/oracle/diag/rdbms/testdb/testdb/trace/alert_testdb.log
2017-04-24 16:15:40 DEBUG mtime of file '/u01/app/oracle/diag/rdbms/testdb/testdb/trace/alert_testdb.log' changed
2017-04-24 16:15:40 DEBUG file '/u01/app/oracle/diag/rdbms/testdb/testdb/trace/alert_testdb.log' was truncated
2017-04-24 16:15:40 INFO input file /u01/app/oracle/diag/rdbms/testdb/testdb/trace/alert_testdb.log was truncated, restarting from beginning
2017-04-24 16:15:40 DEBUG file /u01/app/oracle/diag/rdbms/testdb/testdb/trace/alert_testdb.log already opened

...

section 2

2017-04-24 16:15:42 DEBUG check file: /u01/app/oracle/diag/rdbms/testdb/testdb/trace/alert_testdb.log
2017-04-24 16:15:42 DEBUG mtime of file '/u01/app/oracle/diag/rdbms/testdb/testdb/trace/alert_testdb.log' changed
2017-04-24 16:15:42 DEBUG file size of '/u01/app/oracle/diag/rdbms/testdb/testdb/trace/alert_testdb.log' increased since last read
2017-04-24 16:15:42 DEBUG file '/u01/app/oracle/diag/rdbms/testdb/testdb/trace/alert_testdb.log' has unread data (540975520 > 540709280)
2017-04-24 16:15:42 DEBUG file /u01/app/oracle/diag/rdbms/testdb/testdb/trace/alert_testdb.log already opened

...

section 3

2017-04-24 16:15:44 DEBUG check file: /u01/app/oracle/diag/rdbms/testdb/testdb/trace/alert_testdb.log
2017-04-24 16:15:44 DEBUG mtime of file '/u01/app/oracle/diag/rdbms/testdb/testdb/trace/alert_testdb.log' changed
2017-04-24 16:15:44 DEBUG file '/u01/app/oracle/diag/rdbms/testdb/testdb/trace/alert_testdb.log' was truncated
2017-04-24 16:15:44 INFO input file /u01/app/oracle/diag/rdbms/testdb/testdb/trace/alert_testdb.log was truncated, restarting from beginning
2017-04-24 16:15:44 DEBUG file /u01/app/oracle/diag/rdbms/testdb/testdb/trace/alert_testdb.log already opened

the section2-3  is repeated，and continues to loop.

please help to figure out the reasons，thank you!