Examine the following scenario: The target database instance is running. The most recent backup available for the target database was taken two days ago. Log files switches have occurred in last two days. The target database is duplicated on the same host, using the Recovery Manager (RMAN) duplicate command as follows:
RMAN> RUN { ALLOCATE AUXILIARY CHANNEL aux 1 DEVICE TYPE DISK; DUPLICATE TARGET DATABASE TO auxdb; }
Which statement is true about the duplicate database in this scenario?
A. It contains data till the last backup
B. It contains all data from target database until the current time
C. It contains all data from only the committed transactions in the target database
D. It contains all data except that which is used by the transactions in the current online redo file of target database
从命令可看出，是使用 AUXILIARY CHANNEL 基于 backup-based 的复制数据库(没有 from activedatabase 参数)。 辅助实例通道完成复制的主要工作，关联在目标主机上服务会话和辅助实例。
RMAN 在这个场景下是进行的基于时间点的恢复，因为在线日志不能应用到目标复制数据库上，不指定 until time 的话，是使用最近的一个时间点，即源数据库最近一次归档。
所以源数据库中正在记录事务的重做日志不能包含到 duplicate database 里去。