原文链接：http://blog.sina.com.cn/s/blog_64e166580100xks5.html
如何正确地删除Archivelog：
Archivelog并不能直接得从OS层直接物理删除，因为archivelog的相关信息是记录在controlfile中的，当物理删除后不会改变controlfile的设置。并且在查询相关的动态视图(例如v$archived_log)时，该部分日志仍然标注为存在。也就是说Oracle并不认为这些日志被删除了，所以在删除archivelog的时候，需要我们在其他地方做一些设置。
一、使用RMAN清楚物理删除后的记录
可以使用RMAN来删除archivelog，具体可以按以下步骤操作：
1、物理删除archivelog
2、进入RMAN
3、crosscheck archivelog all;
4、delete expired archivelog all;
这样就在一些Oracle的记录中查不到相应的archivelog记录了。
二、直接使用RMAN删除archivelog
其实在RMAN中是可以使用命令直接将ARCHIVELOG删除的，命令如下：
RMAN> DELETE ARCHIVELOG ALL COMPLETED BEFORE 'SYSDATE-7';
表示删除7天以前的所有archivelog，但是这个命令的缺点是无法对archivelog进行细致的划分。
三、使用RMAN备份achivelog后删除
这是一种最为稳妥的方法了，使用RMAN备份archivelog，备份后全部删除
backup format '/u01/arch_%T_%s_%U' archivelog all delete input;
或者
backup database plus archivelog;
注：我在库上设置了Streams后，使用RMAN删除archivelog会导致报错RMAN-08137: WARNING:
archive log not deleted as it is still needed. 不知道该如何解决，据说是10.2的一个bug，如果真
是bug的话，那只能在OS层设置删除，或用RMAN进行强制删除了。
10g之后的版本，Oracle在RMAN中内置增加了一项归档文件的删除策略，终于，DBA可以仅通过一项配置就
解决该问题了。该策略对应两个值：
APPLIED ON STANDBY：设置为该值时，当通过附加的DELETE INPUT子句删除Standby数据库仍需要的日志
时，会提示RMAN-08137错误。不过用户仍然可以手动地通过DELETE ARCHIVELOG方式删除。
NONE：设置为该值时，则不启用归档文件的删除策略。默认情况下就是NONE。
例如，启用APPLIED ON STANDBY：
RMAN> CONFIGURE ARCHIVELOG DELETION POLICY TO APPLIED ON STANDBY;
new RMAN configuration parameters:
CONFIGURE ARCHIVELOG DELETION POLICY TO APPLIED ON STANDBY;
new RMAN configuration parameters are successfully stored
RMAN> run
{
backup archivelog all delete input format 'ZHSVR044_%d_set=%s_piece=%p_date=%T.ARC.rmn';
}
都知道在controlfile中记录着每一个archivelog的相关信息，当然们在OS下把这些物理文件delete掉后，在我们的
controlfile中仍然记录着这些archivelog的信息，在oracle的OEM管理器中有可视化的日志展现出，当我们手工清除archive目录下的文件后，这些记录并没有被我们从controlfile中清除掉，也就是oracle并不知道这些文件已经不存在了!这时候我们要做手工的清除的话，下面我经过实验，可以尝试这种方法：
1. 进入rman
2. connect target /
3. crosscheck archivelog all;
4. delete expired archivelog all;
这时候我们再去OEM中看就一定看不到，如果你的从来没有做过这个动作的话，我们可以比较从这个动作前的controlfile后动作后的controlfile的大小!
ORACLE正确删除归档并回收空间的方法
ORACLE正确删除归档并回收空间的方法
一个ORACLE归档日志经常满，表现为/oraarchive 这个文件空间占用100％大家一定抱怨ORACLE为何没有归档维护工具，很多人直接删除了事，错了，ORACLE有，而且很智能，可以正确的删除归档和FLASHBACK，不过切记,ORACLE归档日志对于ORACLE的数据恢复和备份非常重要，不到万不得已不要删除归档日志。
删除归档日志的过程
以ORACLE用户身份登录到数据库服务器主机或通过网络连接
进入ORACLE数据备份工具
rman target/
或rman target/@orcl
在命令窗口里面执行
DELETE ARCHIVELOG ALL COMPLETED BEFORE 'SYSDATE-7';
说明
SYSDATA-7，表明当前的系统时间7天前，before关键字表示在7天前的归档日志，如果使用了闪回功能，也会删除闪回的数据。
同样道理，也可以删除从7天前到现在的全部日志，不过这个命令要考虑清楚，做完这个删除，最好马上进行全备份数据库
DELETE ARCHIVELOG FROM TIME 'SYSDATE-7';
UNIX/LINUX下也可以通过FIND找到7天前的归档数据，使用EXEC子操作删除
find /oraarchive -xdev -mtime +7 -name "*.dbf" -exec rm -f {} ;
这样做仍然会在RMAN里留下未管理的归档文件
仍需要在RMAN里执行下面2条命令
crosscheck archivelog all;
delete expired archivelog all;
所以还不如上面的方法好用，不过用FIND的好处就是，可以在条件上，和EXEC子项上做很多操作，实现更复杂的功能
3.简要介绍一下report obsolete命令
使用report obsolete命令报告过期备份
RMAN> report obsolete;
RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 1
Report of obsolete backups and copies
Type Key Completion Time Filename/Handle
-------------------- ------ ------------------ --------------------
Backup Set 125 01-NOV-04
Backup Piece 125 01-NOV-04 /data1/oracle/orabak/full_1_541045804
Backup Set 131 04-NOV-04
Backup Piece 131 04-NOV-04 /data1/oracle/orabak/full_AVATAR2_20041104_131
....
Backup Set 173 06-DEC-04
Backup Piece 173 06-DEC-04 /data1/oracle/orabak/full_AVATAR2_20041206_173
Backup Set 179 11-DEC-04
Backup Piece 179 11-DEC-04 /data1/oracle/orabak/arch544588206.arc
.....
Backup Piece 189 17-DEC-04 /data1/oracle/orabak/arch545106606.arc
Backup Set 190 17-DEC-04
Backup Piece 190 17-DEC-04 /data1/oracle/orabak/arch545106665.arc
Backup Set 191 20-DEC-04
Backup Piece 191 20-DEC-04 /data1/oracle/orabak/arch_AVATAR2_20041220_194
Archive Log 2973 20-DEC-04 /opt/oracle/oradata/avatar2/archive/1_2985.dbf
Archive Log 2971 20-DEC-04 /opt/oracle/oradata/avatar2/archive/1_2984.dbf
.....
Archive Log 2705 17-DEC-04 /opt/oracle/oradata/avatar2/archive/1_2717.dbf
Archive Log 2704 17-DEC-04 /opt/oracle/oradata/avatar2/archive/1_2716.dbf
Archive Log 2703 17-DEC-04 /opt/oracle/oradata/avatar2/archive/1_2715.dbf
Archive Log 2702 17-DEC-04 /opt/oracle/oradata/avatar2/archive/1_2714.dbf
4.使用delete obsolete命令删除过期备份:
RMAN> delete obsolete;
RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 1
using channel ORA_DISK_1
Deleting the following obsolete backups and copies:
Type Key Completion Time Filename/Handle
-------------------- ------ ------------------ --------------------
Backup Set 125 01-NOV-04
Backup Piece 125 01-NOV-04 /data1/oracle/orabak/full_1_541045804
....
Archive Log 2704 17-DEC-04 /opt/oracle/oradata/avatar2/archive/1_2716.dbf
Archive Log 2703 17-DEC-04 /opt/oracle/oradata/avatar2/archive/1_2715.dbf
Archive Log 2702 17-DEC-04 /opt/oracle/oradata/avatar2/archive/1_2714.dbf
Do you really want to delete the above objects (enter YES or NO)? yes
deleted backup piece
backup piece handle=/data1/oracle/orabak/full_AVATAR2_20041206_173 recid=173 stamp=544156241
.....
deleted archive log
archive log filename=/opt/oracle/oradata/avatar2/archive/1_2715.dbf recid=2703 stamp=545108268
deleted archive log
archive log filename=/opt/oracle/oradata/avatar2/archive/1_2714.dbf recid=2702 stamp=545107659
Deleted 286 objects
RMAN> crosscheck archivelog all;
released channel: ORA_DISK_1
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=19 devtype=DISK
specification does not match any archive log in the recovery catalog
5 在rman中用crosscheck检查归档日志,2个归档日志都是失败的:
RMAN> crosscheck archivelog all;
释放的通道: ORA_DISK_1
分配的通道: ORA_DISK_1
通道 ORA_DISK_1: sid=14 devtype=DISK
对归档日志的验证失败
存档日志文件名 =D:ORACLEORADATATESTARCHIVE1_47.DBF 记录 ID=1 时间戳 =572866
683
对归档日志的验证失败
存档日志文件名 =D:ORACLEORADATATESTARCHIVE11_48.DBF 记录 ID=2 时间戳 =57286
6931
已交叉检验的 2 对象
6 试着同步一下,看行不行,结果不行,crosscheck还是失败:
RMAN> resync catalog;
正在启动全部恢复目录的 resync
完成全部 resync
RMAN> crosscheck archivelog all;
释放的通道: ORA_DISK_1
分配的通道: ORA_DISK_1
通道 ORA_DISK_1: sid=14 devtype=DISK
对归档日志的验证失败
存档日志文件名 =D:ORACLEORADATATESTARCHIVE1_47.DBF 记录 ID=1 时间戳 =572866
683
对归档日志的验证失败
存档日志文件名 =D:ORACLEORADATATESTARCHIVE11_48.DBF 记录 ID=2 时间戳 =57286
6931
已交叉检验的 2 对象
7 用list expired看看是否有失效的archive log,证明没有失效的archive log:
RMAN> list expired archivelog all;
说明与恢复目录中的任何存档日志均不匹配
8 更改语言环境试试,结果再次crosscheck,2个archive log 都成功了:
RMAN> exit
恢复管理器完成。
C:>set nls_lang=american_america.zhs16gbk
C:>rman catalogrman/rman@safetarget /
Recovery Manager: Release 9.2.0.1.0 - Production
Copyright (c) 1995, 2002, Oracle Corporation. All rights reserved.
connected to target database: TEST (DBID=1870953724)
connected to recovery catalog database
RMAN> crosscheck archivelog all;
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=9 devtype=DISK
validation succeeded for archived log
archive log filename=D:ORACLEORADATATESTARCHIVE1_47.DBF recid=1 stamp=57286
6683
validation succeeded for archived log
archive log filename=D:ORACLEORADATATESTARCHIVE11_48.DBF recid=2 stamp=5728
66931
Crosschecked 2 objects
删除N天以前的归档日志，有两个命令：
delete archivelog until time 'sysdate-N'
delete archivelog all completed before 'sysdate-N'
看下两者的区别：
RMAN> list archivelog until time 'sysdate-1';
List of Archived Log Copies
Key Thrd Seq S Low Time Name
------- ---- ------- - ---------- ----
7 1 5 A 13-7月 -11 +RECOVERY/edu/archivelog/2011_07_13/thread_1_seq_5.259.756405771
10 1 6 A 13-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_6.263.756453607
16 1 7 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_7.268.756467343
17 1 8 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_8.269.756467345
18 1 9 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_9.270.756467399
19 1 10 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_10.271.756467403
21 1 11 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_11.272.756467511
22 1 12 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_12.274.756467515
23 1 13 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_13.275.756467521
25 1 14 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_14.276.756467527
26 1 15 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_15.278.756467635
27 1 16 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_16.279.756484801
29 1 17 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_15/thread_1_seq_17.256.756576859
5 2 2 A 13-7月 -11 +RECOVERY/edu/archivelog/2011_07_13/thread_2_seq_2.257.756405175
8 2 3 A 13-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_2_seq_3.260.756442807
9 2 4 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_2_seq_4.261.756442823
11 2 5 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_2_seq_5.262.756453607
12 2 6 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_2_seq_6.264.756453623
13 2 7 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_2_seq_7.265.756467273
14 2 8 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_2_seq_8.266.756467279
15 2 9 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_2_seq_9.267.756467279
20 2 10 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_2_seq_10.273.756467511
24 2 11 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_2_seq_11.277.756467533
28 2 12 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_15/thread_2_seq_12.280.756566433
最大sequence为17和12
再看：
RMAN> list archivelog all completed before 'sysdate-1';
List of Archived Log Copies
Key Thrd Seq S Low Time Name
------- ---- ------- - ---------- ----
7 1 5 A 13-7月 -11 +RECOVERY/edu/archivelog/2011_07_13/thread_1_seq_5.259.756405771
10 1 6 A 13-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_6.263.756453607
16 1 7 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_7.268.756467343
17 1 8 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_8.269.756467345
18 1 9 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_9.270.756467399
19 1 10 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_10.271.756467403
21 1 11 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_11.272.756467511
22 1 12 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_12.274.756467515
23 1 13 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_13.275.756467521
25 1 14 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_14.276.756467527
26 1 15 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_15.278.756467635
27 1 16 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_1_seq_16.279.756484801
5 2 2 A 13-7月 -11 +RECOVERY/edu/archivelog/2011_07_13/thread_2_seq_2.257.756405175
8 2 3 A 13-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_2_seq_3.260.756442807
9 2 4 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_2_seq_4.261.756442823
11 2 5 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_2_seq_5.262.756453607
12 2 6 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_2_seq_6.264.756453623
13 2 7 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_2_seq_7.265.756467273
14 2 8 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_2_seq_8.266.756467279
15 2 9 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_2_seq_9.267.756467279
20 2 10 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_2_seq_10.273.756467511
24 2 11 A 14-7月 -11 +RECOVERY/edu/archivelog/2011_07_14/thread_2_seq_11.277.756467533
详细看下 这些日志的区别：
QL> select THREAD#,sequence#,FIRST_TIME,NEXT_TIME,COMPLETION_TIME
2 from v$archived_log order by thread#,sequence#;
THREAD# SEQUENCE# FIRST_TIME NEXT_TIME COMPLETION_TIME
---------- ---------- ----------------- ----------------- -----------------
1 1 20110713 14:57:58 20110713 14:58:42 20110713 14:58:49
1 2 20110713 14:58:42 20110713 14:59:00 20110713 14:59:18
1 3 20110713 14:59:00 20110713 15:02:31 20110713 15:02:36
1 4 20110713 15:02:31 20110713 16:32:50 20110713 16:32:57
1 5 20110713 16:32:50 20110713 16:41:40 20110713 16:42:51
1 6 20110713 16:41:40 20110714 06:00:07 20110714 06:00:08
1 7 20110714 06:00:07 20110714 09:26:57 20110714 09:49:04
1 8 20110714 09:26:57 20110714 09:46:55 20110714 09:49:04
1 9 20110714 09:46:55 20110714 09:49:58 20110714 09:50:06
1 10 20110714 09:49:58 20110714 09:50:02 20110714 09:50:09
1 11 20110714 09:50:02 20110714 09:51:49 20110714 09:51:59
THREAD# SEQUENCE# FIRST_TIME NEXT_TIME COMPLETION_TIME
---------- ---------- ----------------- ----------------- -----------------
1 12 20110714 09:51:49 20110714 09:51:55 20110714 09:52:05
1 13 20110714 09:51:55 20110714 09:52:01 20110714 09:52:10
1 14 20110714 09:52:01 20110714 09:52:07 20110714 09:52:13
1 15 20110714 09:52:07 20110714 09:53:54 20110714 09:53:59
1 16 20110714 09:53:54 20110714 14:40:01 20110714 14:40:05
1 17 20110714 14:40:01 20110715 16:14:19 20110715 16:14:20
1 18 20110715 16:14:19 20110715 16:15:46 20110715 16:15:47
2 1 20110713 15:14:43 20110713 16:15:41 20110713 16:17:14
2 2 20110713 16:15:41 20110713 16:32:50 20110713 16:32:54
2 3 20110713 16:32:50 20110714 03:00:07 20110714 03:00:12
2 4 20110714 03:00:07 20110714 03:00:23 20110714 03:00:27
THREAD# SEQUENCE# FIRST_TIME NEXT_TIME COMPLETION_TIME
---------- ---------- ----------------- ----------------- -----------------
2 5 20110714 03:00:23 20110714 06:00:06 20110714 06:00:11
2 6 20110714 06:00:06 20110714 06:00:22 20110714 06:00:27
2 7 20110714 06:00:22 20110714 06:00:37 20110714 09:47:56
2 8 20110714 06:00:37 20110714 09:26:56 20110714 09:48:05
2 9 20110714 09:26:56 20110714 09:47:56 20110714 09:48:05
2 10 20110714 09:47:56 20110714 09:51:51 20110714 09:51:52
2 11 20110714 09:51:51 20110714 09:52:12 20110714 09:52:12
2 12 20110714 09:52:12 20110715 13:20:33 20110715 13:20:37
区别已经很明显：
list archivelog until time 'sysdate-1'; 此时是按照归档日志开始时间即fisrt_time作为截止时间
list archivelog all completed before 'sysdate-1' 是按照归档日志完成时间即completion_time作为截止时间
试想如果删除归档日志，还是采用delete archivelog all completed before 'sysdate-N'