在开发环境及UAT环境经常碰到需要清除归档日志的情形，对于这个问题方法有很多。可以直接使用rm方式清除归档日志，也可以使用find命令来查找符合条件的记录来清除归档日志，或者直接写个shell脚本来搞定。这样在DEV或者UAT还可以，但是在Prod环境还是建议使用RMAN提供的命令来搞定比较妥当。因为rm，find方式删除了实际的归档日志也释放了空间，但对应的存储在控制文件中的归档信息并没有彻底清除。依旧占用着一些空间未能及时清除而需要控制文件通过age out方式来释放空间。本文描述了使用RMAN方式来清除归档日志，同时也可以将其部署到shell脚本中使用。
1、清除归档日志的方式
a、手动删除
使用rm 或者find方式来删除，通过该方式删除之后，在RMAN下可以通过 crosscheck archivelog all 校验归档是否失效，如下面的操作:
rm -rf arch_816906485_1_10.arc
find /u02/database/GOBO1/archive/ -ctime +0 -delete
RMAN> crosscheck archivelog all
b、使用RMAN方式清除
RMAN清除方式会自动清除磁盘上的归档日志文件，同时会释放控制文件中对应的归档日志的归档信息。
可以基于不同的条件来清除归档日志，如基于SCN，基于SEQUENCE，基于TIME等方式。
对于上述的三种方式又可以配合from, until, between .. and .. 等等子句来限定范围，方式灵活多变。
下面的命令用于校验归档日志的有效性，列出无效的归档日志，以及以何种方式清除归档日志，列出几种常用的:
crosscheck archivelog all; --->校验日志的可用性
list expired archivelog all; --->列出所有失效的归档日志
delete archivelog until sequence 16; --->删除log sequence为16及16之前的所有归档日志
delete archivelog all completed before 'sysdate-7'; --->删除系统时间7天以前的归档日志，不会删除闪回区有效的归档日志
delete archivelog all completed before 'sysdate - 1'; --->同上，1天以前的
delete archivelog from time 'sysdate-1'; --->注意这个命令，删除系统时间1天以内到现在的归档日志
delete noprompt archivelog all completed before 'sysdate'; --->该命令清除所有的归档日志
delete noprompt archivelog all; --->同上一命令
2、演练使用RMAN清除归档日志
robin@SZDB:~> export ORACLE_SID=GOBO1
robin@SZDB:~> rman target /
Recovery Manager: Release 10.2.0.3.0 - Production on Thu Jul 11 17:07:00 2013
Copyright (c) 1982, 2005, Oracle. All rights reserved.
connected to target database: GOBO1 (DBID=733951103)
RMAN> host;
robin@SZDB:~> cd /u02/database/GOBO1/archive/
robin@SZDB:/u02/database/GOBO1/archive> ls
arch_816906485_1_10.arc arch_816906485_1_12.arc
arch_816906485_1_11.arc arch_816906485_1_13.arc
............
robin@SZDB:/u02/database/GOBO1/archive> rm -rf arch_816906485_1_10.arc arch_816906485_1_11.arc arch_816906485_1_12.arc
robin@SZDB:/u02/database/GOBO1/archive> exit;
exit
host command complete
RMAN> crosscheck archivelog all;
released channel: ORA_DISK_1
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=1075 devtype=DISK
archive log filename=/u02/database/GOBO1/archive/arch_816906485_1_9.arc recid=2085 stamp=817211151
validation failed for archived log
archive log filename=/u02/database/GOBO1/archive/arch_816906485_1_10.arc recid=2086 stamp=817250793
..............
validation succeeded for archived log
archive log filename=/u02/database/GOBO1/archive/arch_816906485_1_90.arc recid=2166 stamp=820458049
Crosschecked 83 objects
RMAN> list expired archivelog all;
List of Archived Log Copies
Key Thrd Seq S Low Time Name
------- ---- ------- - ----------------- ----
2086 1 10 X 20130604 11:05:51 /u02/database/GOBO1/archive/arch_816906485_1_10.arc
2087 1 11 X 20130604 22:06:17 /u02/database/GOBO1/archive/arch_816906485_1_11.arc
2088 1 12 X 20130605 19:30:53 /u02/database/GOBO1/archive/arch_816906485_1_12.arc
RMAN> delete archivelog until sequence 16;
released channel: ORA_DISK_1
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=1075 devtype=DISK
List of Archived Log Copies
Key Thrd Seq S Low Time Name
------- ---- ------- - ----------------- ----
2084 1 8 A 20130604 09:53:17 /u02/database/GOBO1/archive/arch_816906485_1_8.arc
.................
2092 1 16 A 20130607 22:03:23 /u02/database/GOBO1/archive/arch_816906485_1_16.arc
Do you really want to delete the above objects (enter YES or NO)? yes
...............
deleted archive log
archive log filename=/u02/database/GOBO1/archive/arch_816906485_1_16.arc recid=2092 stamp=817516861
Deleted 9 objects
RMAN> delete archivelog all completed before 'sysdate-7';
released channel: ORA_DISK_1
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=1075 devtype=DISK
List of Archived Log Copies
Key Thrd Seq S Low Time Name
------- ---- ------- - ----------------- ----
2093 1 17 A 20130608 00:01:00 /u02/database/GOBO1/archive/arch_816906485_1_17.arc
2094 1 18 A 20130608 18:00:17 /u02/database/GOBO1/archive/arch_816906485_1_18.arc
...........
deleted archive log
archive log filename=/u02/database/GOBO1/archive/arch_816906485_1_72.arc recid=2148 stamp=819847035
Deleted 56 objects
RMAN> list copy of database archivelog all;
List of Archived Log Copies
Key Thrd Seq S Low Time Name
------- ---- ------- - ----------------- ----
2149 1 73 A 20130703 23:17:13 /u02/database/GOBO1/archive/arch_816906485_1_73.arc
2150 1 74 A 20130704 22:00:19 /u02/database/GOBO1/archive/arch_816906485_1_74.arc
2151 1 75 A 20130704 22:04:40 /u02/database/GOBO1/archive/arch_816906485_1_75.arc
...............
2164 1 88 A 20130709 23:19:34 /u02/database/GOBO1/archive/arch_816906485_1_88.arc
2165 1 89 A 20130710 13:00:34 /u02/database/GOBO1/archive/arch_816906485_1_89.arc
2166 1 90 A 20130710 22:02:44 /u02/database/GOBO1/archive/arch_816906485_1_90.arc
RMAN> delete archivelog from time 'sysdate-1';
released channel: ORA_DISK_1
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=1075 devtype=DISK
List of Archived Log Copies
Key Thrd Seq S Low Time Name
------- ---- ------- - ----------------- ----
2165 1 89 A 20130710 13:00:34 /u02/database/GOBO1/archive/arch_816906485_1_89.arc
2166 1 90 A 20130710 22:02:44 /u02/database/GOBO1/archive/arch_816906485_1_90.arc
Do you really want to delete the above objects (enter YES or NO)? yes
deleted archive log
archive log filename=/u02/database/GOBO1/archive/arch_816906485_1_89.arc recid=2165 stamp=820447373
deleted archive log
archive log filename=/u02/database/GOBO1/archive/arch_816906485_1_90.arc recid=2166 stamp=820458049
Deleted 2 objects
RMAN> delete archivelog all completed before 'sysdate - 1';
released channel: ORA_DISK_1
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=1075 devtype=DISK
List of Archived Log Copies
Key Thrd Seq S Low Time Name
------- ---- ------- - ----------------- ----
2149 1 73 A 20130703 23:17:13 /u02/database/GOBO1/archive/arch_816906485_1_73.arc
.......................
2164 1 88 A 20130709 23:19:34 /u02/database/GOBO1/archive/arch_816906485_1_88.arc
Do you really want to delete the above objects (enter YES or NO)? yes
................
archive log filename=/u02/database/GOBO1/archive/arch_816906485_1_88.arc recid=2164 stamp=820414835
Deleted 16 objects
RMAN> sql " alter system archive log current";
sql statement: alter system archive log current
RMAN> list copy of archivelog all;
List of Archived Log Copies
Key Thrd Seq S Low Time Name
------- ---- ------- - ----------------- ----
2167 1 91 A 20130711 01:00:48 /u02/database/GOBO1/archive/arch_816906485_1_91.arc
RMAN> delete noprompt archivelog all completed before 'sysdate';
released channel: ORA_DISK_1
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=1075 devtype=DISK
List of Archived Log Copies
Key Thrd Seq S Low Time Name
------- ---- ------- - ----------------- ----
2167 1 91 A 20130711 01:00:48 /u02/database/GOBO1/archive/arch_816906485_1_91.arc
deleted archive log
archive log filename=/u02/database/GOBO1/archive/arch_816906485_1_91.arc recid=2167 stamp=820517964
Deleted 1 objects
3、清除归档日志简单的shell脚本
#对于RAC环境或者ASM需要清除archive，使用shell脚本调用RMAN是比较妥当的方式
#其次，如果你的archive位于闪回区，制定合理的保留策略，也可以让Oracle自动老化无用的归档日志
robin@SZDB:~/dba_scripts/custom/bin> more clean_arch.sh
# +-------------------------------------------------------+
# + Clean archived log as specified time |
# + Author : Robinson |
# + Blog : http://blog.csdn.net/robinson_0612 |
# + Usage : |
# + clean_arch.sh $ORACLE_SID |
# +-------------------------------------------------------+
#
#!/bin/bash
# --------------------
# Define variable
# --------------------
if [ -f ~/.bash_profile ]; then
. ~/.bash_profile
fi
if [ -z "${1}" ];then
echo "Usage: "
echo " `basename $0` ORACLE_SID"
exit 1
fi
ORACLE_SID=$1; export ORACLE_SID
$ORACLE_HOME/bin/rman log=/users/robin/log/rman.log <<EOF
connect target /
run{
crosscheck archivelog all;
delete noprompt expired archivelog all;
delete noprompt archivelog all completed before 'sysdate - 1';
}
exit;
EOF
exit
4、小结
a、归档日志清除的方法最好是在RMAN方式下完成，这样子是最彻底的清除方式
b、对于生产环境应考虑在RMAN备份的时候清除归档日志，如backup archivelog all时使用delete input与delete all input清除归档日志
c、如果备份期间不清除归档日志则arch会很大，造成归档磁盘满而导致归档失败。建议还是删除或考虑存放到闪回区
d、如果清除大部分又想保留最近的，则使用delete noprompt archivelog all completed before 'sysdate - n'方式
e、详细的清除归档日志语法: http://docs.oracle.com/cd/B19306_01/backup.102/b14194/rcmsynta008.htm#RCMRF106
