v$flashback_database_log
v$flashback_database_logfile
v$flashback_database_stat
v$flash_recovery_area_usage

[oracle@rac1 archive]$ sqlplus / as sysdba

SQL*Plus: Release 10.2.0.1.0 - Production on Fri Sep 7 14:19:19 2007

Copyright (c) 1982, 2005, Oracle. All rights reserved.

Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> alter session set nls_date_format='yyyy-mm-dd hh24:mi:ss';

Session altered.

v$flashback_database_log 记录了可以flashback log的开始时间点和需要的flashback data大小。

SQL> select * from v$flashback_database_log;

OLDEST_FLASHBACK_SCN OLDEST_FLASHBACK_TI RETENTION_TARGET FLASHBACK_SIZE ESTIMATED_FLASHBACK_SIZE
-------------------- ------------------- ---------------- -------------- ------------------------
2142613 2007-09-07 11:32:40 30 28442624 2741760

v$flashback_database_logfile 记录了数据库产生的闪回日志,和archive一样,记录了产生的时间和SCN。
SQL> col name format a50
SQL> select * from v$flashback_database_logfile;

NAME LOG# THREAD# SEQUENCE# BYTES FIRST_CHANGE# FIRST_TIME
-------------------------------------------------- ---------- ---------- ---------- ---------- ------------- -------------------
/oradata/RAC/flashback/o1_mf_3g1klqnt_.flb 1 1 1 8192000 2142692 2007-09-07 11:32:40
/oradata/RAC/flashback/o1_mf_3g1pomlb_.flb 2 1 2 4096000 2148586 2007-09-07 12:59:31
/oradata/RAC/flashback/o1_mf_3g1s5b6m_.flb 3 1 3 3981312 2152195 2007-09-07 13:42:01
/oradata/RAC/flashback/o1_mf_3g1t7lwc_.flb 4 1 4 3981312 2153513 2007-09-07 14:00:18
/oradata/RAC/flashback/o1_mf_3g1v2tdf_.flb 5 2 1 8192000 2155686 2007-09-07 14:15:16

v$flashback_database_stat 是FLASHBACK RECOVERY ARED的统计视图,记录了I/O的变化情况,可以观察时间段内I/O的活动信息
SQL> select * from v$flashback_database_stat;

BEGIN_TIME END_TIME FLASHBACK_DATA DB_DATA REDO_DATA ESTIMATED_FLASHBACK_SIZE
------------------- ------------------- -------------- ---------- ---------- ------------------------
2007-09-07 14:48:49 2007-09-07 15:49:17 11747328 17211392 5825536 3808256

v$flash_recovery_area_usage 统计了FLASHBACK RECOVERY AREA区域的使用情况
SQL> select * from v$flash_recovery_area_usage;

FILE_TYPE PERCENT_SPACE_USED PERCENT_SPACE_RECLAIMABLE NUMBER_OF_FILES
------------ ------------------ ------------------------- ---------------
CONTROLFILE .71 0 1
ONLINELOG 0 0 0
ARCHIVELOG 0 0 0
BACKUPPIECE 49.31 0 4
IMAGECOPY 0 0 0
FLASHBACKLOG 1.32 .56 5
也可以用操作系统来统计FRA的使用空间.

通过上面的几个视图我们可以观察FRA的使用情况.