Linux下的strace可以帮助我们跟踪一下程序的系统调用；LGWR是Oracle中的一个重要进程，专门负责将redo写入online redo log中。
01 open("/u02/oradata/mydb/redolog/group04/redo05a.log", O_RDONLY) = 60
02 open("/u02/oradata/mydb/redolog/group04/redo05a.log", O_RDWR|O_SYNC) = 60
03 open("/u02/oradata/mydb/redolog/group04/redo05b.log", O_RDONLY) = 61
04 open("/u02/oradata/mydb/redolog/group04/redo05b.log", O_RDWR|O_SYNC) = 61
05 open("/proc/5164/stat", O_RDONLY) = 62
06 open("/u01/app/admin/mydb/bdump/alert_mydb.log", O_WRONLY|O_CREAT|O_APPEND, 0664) = 8
07 open("/u01/app/admin/mydb/bdump/alert_mydb.log", O_WRONLY|O_CREAT|O_APPEND, 0664) = 8
08 open("/u01/app/admin/mydb/bdump/alert_mydb.log", O_WRONLY|O_CREAT|O_APPEND, 0664) = 8
09 .......
10 .......
11 .......
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