V$FLASH_RECOVERY_AREA_USAGE definition in Oracle Database 11.2
V$FLASH_RECOVERY_AREA_USAGE
select
file_type, -- FILE_TYPE VARCHAR2(20)
percent_space_used, -- PERCENT_SPACE_USED NUMBER
percent_space_reclaimable, -- PERCENT_SPACE_RECLAIMABLE NUMBER
number_of_files -- NUMBER_OF_FILES NUMBER
from
v$recovery_area_usage