SQL> show parameter db_recovery

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
db_recovery_file_dest string g:oracleproduct10.2.0flash
_recovery_area
db_recovery_file_dest_size big integer 2G
SQL>
--=================================
SQL> select * from v$flash_recovery_area_usage;

FILE_TYPE PERCENT_SPACE_USED PERCENT_SPACE_RECLAIMABLE NUMBER_OF_FILES
------------ ------------------ ------------------------- ---------------
CONTROLFILE 0 0 0
ONLINELOG 0 0 0
ARCHIVELOG 23.19 0 13
BACKUPPIECE 9.36 0 2
IMAGECOPY 67.33 0 13
FLASHBACKLOG 0 0 0

6 rows selected.

SQL> select sum(PERCENT_SPACE_USED) from v$flash_recovery_area_usage;

SUM(PERCENT_SPACE_USED)
-----------------------
99.88

--===============================================
SQL> desc v$recovery_file_dest
Name Null? Type
----------------------------------------- -------- ----------------------------
NAME VARCHAR2(513)
SPACE_LIMIT NUMBER
SPACE_USED NUMBER
SPACE_RECLAIMABLE NUMBER
NUMBER_OF_FILES NUMBER

SQL> col name format a45
SQL> select * from v$recovery_file_dest;

NAME SPACE_LIMIT SPACE_USED SPACE_RECLAIMABLE NUMBER_OF_FILES
--------------------------------------------- ----------- ---------- ----------------- ---------------
g:oracleproduct10.2.0flash_recovery_area 2147483648 2144909312 0 28

SQL> select round(100*(a.space_used/space_limit),2) from v$recovery_file_dest a;

ROUND(100*(A.SPACE_USED/SPACE_LIMIT),2)
--=============================================
99.88