Oracle alert_sid.log属组变为root不影响数据库正常运行

在一次数据库检查过程中，发现数据库近一天内没有任何日志输出，甚至没有正常切换归档日志的信息；但数据库运行正常，业务运行正常：

手动执行alter system switch logfile；正常，但alert_sid.log中没有日志信息：

如下：

[root@test bdump]# date
Sat May  7 09:21:16 CST 2016
[root@test bdump]# tail -f alert_test.log 
Completed: ALTER DATABASE OPEN
Fri May 06 08:57:25 CST 2016
Thread 1 advanced to log sequence 9546 (LGWR switch)
  Current log# 1 seq# 9546 mem# 0: /test/oradata/test/onlinelog/o1_mf_1_9oyvfc0w_.log
Fri May 06 08:59:30 CST 2016
Thread 1 advanced to log sequence 9547 (LGWR switch)
  Current log# 2 seq# 9547 mem# 0: /test/oradata/test/onlinelog/o1_mf_2_9oyvfjp3_.log
当前时间为5月7日9:21:16，但alert_test.log日志信息最终截止于5月6日8:59:30。

检查确认该文件最后修改时间为5月6日9:01：

[root@test bdump]# ll
total 4504

-rw-r----- 1 root   root     1825837 May  6 09:01 alert_test.log

于是修改如下：

[root@test bdump]# chown oracle:oinstall alert_test.log 

再次查看alert_test.log，归档日志切换正常，日志记录信息正常：

[root@test bdump]# tail -f alert_test.log 
Completed: ALTER DATABASE OPEN
Fri May 06 08:57:25 CST 2016
Thread 1 advanced to log sequence 9546 (LGWR switch)
  Current log# 1 seq# 9546 mem# 0: /test/oradata/test/onlinelog/o1_mf_1_9oyvfc0w_.log
Fri May 06 08:59:30 CST 2016
Thread 1 advanced to log sequence 9547 (LGWR switch)
  Current log# 2 seq# 9547 mem# 0: /test/oradata/test/onlinelog/o1_mf_2_9oyvfjp3_.log
Fri May 06 09:00:36 CST 2016
Thread 1 advanced to log sequence 9548 (LGWR switch)
  Current log# 3 seq# 9548 mem# 0: /test/oradata/test/onlinelog/o1_mf_3_9oyvfpgh_.log
Sat May 07 09:21:26 CST 2016
Thread 1 advanced to log sequence 9603 (LGWR switch)
  Current log# 3 seq# 9603 mem# 0: /test/oradata/test/onlinelog/o1_mf_3_9oyvfpgh_.log