Your DB_RECOVERY_FILE_DEST_SIZE IS 8G,Currently,5G of the space is used of which 4G consists of obsolete backups, You execute this command;

SQL> ALTER SYSTEM SET db_recovery_file_dest_size=2G;

What is the outcome?

A) It changes DB_RECOVERY_FILE_DEST_SIZE to 2G and deletes the obsolete backups

B) It changes DB_RECOVERY_FILE_DEST_SIZE to 5G

C) It fails because DB_RECOVERY_FILE_DEST_SIZE is a static parameter

D) It changes DB_RECOVERY_FILE_DEST_SIZE to 2G without deleting valid backups

E) It fails because the new size is less than 5G

Answer: D (验证过)

CUUG：因为当前还有空闲的空间 3G,所以无需删除有效和无效的备份。

赵：网友选 A 待验证。个人认为有效的备份只有 1G，小于被修改后的 2G，不需要删除过时的备份。

题译：DB_Recovery_file_DEST_size 为 8G，目前使用的空间为 5G，其中 4G 由过时的备份组成。

其他：A 实测不会删除