案例：Oracle数据库10g中释放flash_recovery_area解决ORA-19815错误。
错误现象：备份Oracle数据库10g时出现下面的错误：
ORA-19815: WARNING: db_recovery_file_dest_size of 2147483648 bytes is 100.00% used, and has 0 remaining bytes available.
*************************************************************
You have the following choices to free up space from
flash recovery area:
1. Consider changing your RMAN retention policy.
If you are using dataguard, then consider changing your
RMAN archivelog deletion policy.
2. Backup files to tertiary device such as tape using the
RMAN command BACKUP RECOVERY AREA.
3. Add disk space and increase the db_recovery_file_dest_size
parameter to reflect the new space.
4. Delete unncessary files using the RMAN DELETE command.
If an OS command was used to delete files, then use
RMAN CROSSCHECK and DELETE EXPIRED commands.
*************************************************************
此时flash_recovery_area已经手工释放空间，即使切换到一个全新的磁盘也无法解决此问题。
继续连接数据库的查询：
$ sqlplus "/ as sysdba"
SQL*Plus: Release 10.1.0.2.0 - Production on Mon Mar 28 11:45:30 2005
Copyright (c) 1982, 2004, Oracle. All rights reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.1.0.2.0 - 64bit Production
With the Partitioning, OLAP and Data Mining options
SYS AS SYSDBA on 28-MAR-05 >set liesize 120
SP2-0158: unknown SET option "liesize"
SYS AS SYSDBA on 28-MAR-05 >set linesize 120
SYS AS SYSDBA on 28-MAR-05 >SELECT substr(name, 1, 30) name, space_limit AS quota,
2 space_used AS used,
3 space_reclaimable AS reclaimable,
4 number_of_files AS files
5 FROM v$recovery_file_dest ;
NAME QUOTA USED RECLAIMABLE FILES
---------------------------- ---------- ---------- ----------- ----------
/data5/flash_recovery_area 2147483648 2144863232 0 227
此时发现仍然记录了227个文件，USED空间仍然未被释放。
继续使用rman登录数据库来进行crosscheck：
$ rman target /
Recovery Manager: Release 10.1.0.2.0 - 64bit Production
Copyright (c) 1995, 2004, Oracle. All rights reserved.
connected to target database: EYGLE (DBID=1337390772)
RMAN> crosscheck archivelog all;
using target database controlfile instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=144 devtype=DISK
validation failed for archived log
archive log filename=/opt/oracle/flash_recovery_area/EYGLE/
archivelog/2004_05_17/o1_mf_1_790_0bjq36ps_.arc recid=1 stamp=526401126
validation failed for archived log
archive log filename=/opt/oracle/flash_recovery_area/EYGLE/
archivelog/2004_05_17/o1_mf_1_791_0bkbcy7x_.arc recid=2 stamp=526420862
validation failed for archived log
archive log filename=/opt/oracle/flash_recovery_area/EYGLE/
archivelog/2004_05_17/o1_mf_1_792_0bkkds4d_.arc recid=3 stamp=526428057
.......
archive log filename=/opt/oracle/flash_recovery_area/EYGLE/
archivelog/2004_07_16/o1_mf_1_1014_0hh3zsrp_.arc recid=225 stamp=531678074
validation failed for archived log
archive log filename=/opt/oracle/flash_recovery_area/EYGLE/
archivelog/2004_07_16/o1_mf_1_1015_0hh40qyp_.arc recid=226 stamp=531678104
validation failed for archived log
archive log filename=/opt/oracle/flash_recovery_area/EYGLE/
archivelog/2004_07_16/o1_mf_1_1016_0hh41jqq_.arc recid=227 stamp=531678129
Crosschecked 227 objects
RMAN> delete expired archivelog all;
released channel: ORA_DISK_1
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=144 devtype=DISK
List of Archived Log Copies
Key Thrd Seq S Low Time Name
------- ---- ------- - --------- ----
1 1 790 X 17-MAY-04 /opt/oracle/flash_recovery_area/EYGLE/
archivelog/2004_05_17/o1_mf_1_790_0bjq36ps_.arc
2 1 791 X 17-MAY-04 /opt/oracle/flash_recovery_area/EYGLE/
archivelog/2004_05_17/o1_mf_1_791_0bkbcy7x_.arc
3 1 792 X 17-MAY-04 /opt/oracle/flash_recovery_area/EYGLE/
archivelog/2004_05_17/o1_mf_1_792_0bkkds4d_.arc
.......
225 1 1014 X 16-JUL-04 /opt/oracle/flash_recovery_area/EYGLE/
archivelog/2004_07_16/o1_mf_1_1014_0hh3zsrp_.arc
226 1 1015 X 16-JUL-04 /opt/oracle/flash_recovery_area/EYGLE/
archivelog/2004_07_16/o1_mf_1_1015_0hh40qyp_.arc
227 1 1016 X 16-JUL-04 /opt/oracle/flash_recovery_area/EYGLE/
archivelog/2004_07_16/o1_mf_1_1016_0hh41jqq_.arc
Do you really want to delete the above objects (enter YES or NO)? YES
deleted archive log
archive log filename=/opt/oracle/flash_recovery_area/EYGLE/
archivelog/2004_05_17/o1_mf_1_790_0bjq36ps_.arc recid=1 stamp=526401126
deleted archive log
archive log filename=/opt/oracle/flash_recovery_area/EYGLE/
archivelog/2004_05_17/o1_mf_1_791_0bkbcy7x_.arc recid=2 stamp=526420862
deleted archive log
......
archive log filename=/opt/oracle/flash_recovery_area/EYGLE/
archivelog/2004_07_16/o1_mf_1_1014_0hh3zsrp_.arc recid=225 stamp=531678074
deleted archive log
archive log filename=/opt/oracle/flash_recovery_area/EYGLE/
archivelog/2004_07_16/o1_mf_1_1015_0hh40qyp_.arc recid=226 stamp=531678104
deleted archive log
archive log filename=/opt/oracle/flash_recovery_area/EYGLE/
archivelog/2004_07_16/o1_mf_1_1016_0hh41jqq_.arc recid=227 stamp=531678129
Deleted 227 EXPIRED objects
RMAN> exit
Recovery Manager complete.
此时空间得到释放:
$ sqlplus "/ as sysdba"
SQL*Plus: Release 10.1.0.2.0 - Production on Mon Mar 28 12:02:19 2005
Copyright (c) 1982, 2004, Oracle. All rights reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.1.0.2.0 - 64bit Production
With the Partitioning, OLAP and Data Mining options
SYS AS SYSDBA on 28-MAR-05 >SELECT substr(name, 1, 30) name, space_limit AS quota,
2 space_used AS used,
3 space_reclaimable AS reclaimable,
4 number_of_files AS files
5 FROM v$recovery_file_dest ;
NAME QUOTA USED RECLAIMABLE FILES
---------------------------- ---------- ---------- ----------- ----------
/data5/flash_recovery_area 2147483648 9959424 0 1
SYS AS SYSDBA on 28-MAR-05 >
解决方法：
可以通过执行如下命令:
RMAN> backup recovery area来解决此问题。
（注：将闪回区的内容备份到第三方介质，同样可以解决此问题）
