You configured the Fast Recovery Area (FRA) for your database. The database instance is in archivelog mode. The default location for the archived redo log files is the FRA.
Which two files are removed automatically if space is required in the FRA as per the retention policy?

A. archived redo log files that have multiple copies in a different archive location
B. flashback logs
C. user-managed backups of data files and control files
D. RMAN backups that are obsolete

Answer: BD

【解析】
快速恢复区域可以包含控制文件,联机重做日志,归档的重做日志,闪回日志和RMAN备份。
恢复区域中的文件分为永久文件和临时文件。永久文件是数据库实例使用的活动文件。所有非永久文件都是临时文件。通常,Oracle数据库最终会在备份保留策略下删除已经过期的临时文件,或者删除已备份到磁带的临时文件。
数据文件和控制文件属于永久文件不能删除,归档日志可以被删除,但是非快速恢复区的归档日志是不会被删除的。
【官方手册】
https://docs.oracle.com/en/database/oracle/oracle-database/12.2/bradv/configuring-rman-client-basic.html#GUID-302339EC-EE0F-45FB-9862-BB2BA138AA13