注：在11g,理论上主库的ARC进程和备库的RFS、MRP进程在某些情况都有可能处理gap.
8. 为了进一步确定是MRP通过FAL取了gap文件，我将主库的密码修改了一下，结果MRP的trace中报错：FAL[client, MRP0]，说明是通过FAL取的。
*** 2012-03-29 21:18:15.964 4265 krsh.c
Error 1031 received logging on to the standby
*** 2012-03-29 21:18:15.964 4265 krsh.c
FAL[client, MRP0]: Error 1031 connecting to PRIMARY for fetching gap sequence