oracle@ps251n2s:[/opt/oracle/archive/db] ls -ltr |more
total 3059881082
-rw-r-----? 1 oracle? ? oinstall? 725320704 May 20? 2016 1_1_91233774.dbf
-rw-rw----? 1 oracle? ? oinstall? 1756937216 Jun? 7? 2016 1_2_91233774.dbf
-rw-rw----? 1 oracle? ? oinstall? 1756731392 Jun 21? 2016 1_3_91233774.dbf
-rw-rw----? 1 oracle? ? oinstall? 1758001152 Jul? 3? 2016 1_4_91233774.dbf
-rw-rw----? 1 oracle? ? oinstall? 1756729344 Jul 15? 2016 1_5_91233774.dbf
-rw-rw----? 1 oracle? ? oinstall? 1765750784 Jul 26 22:00 1_6_91233774.dbf
-rw-rw----? 1 oracle? ? oinstall? 1760346112 Aug? 6 14:04 1_7_91233774.dbf
......

使用RMAN list archivelog all;查看日志也没有显示旧归档日志的记录

RMAN> list archivelog all;
?
using target database control file instead of recovery catalog
List of Archived Log Copies for database with db_unique_name DBS
=====================================================================
?
Key? ? Thrd Seq? ? S Low Time?
------- ---- ------- - ---------
1206? ? 1? ? 1206? ? A 14-JAN-17
? ? ? ? Name: /opt/oracle/archive/db/1_1206_91233774.dbf
?
1207? ? 1? ? 1207? ? A 14-JAN-17
? ? ? ? Name: /opt/oracle/archive/db/1_1207_91233774.dbf
?
1208? ? 1? ? 1208? ? A 14-JAN-17
? ? ? ? Name: /opt/oracle/archive/db/1_1208_91233774.dbf
......

使用crosscheck检查也没有查到旧归档日志记录
RMAN> crosscheck archivelog all;
?
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=16 device type=DISK
validation succeeded for archived log
archived log file name=/opt/oracle/archive/db/1_1206_91233774.dbf RECID=1206 STAMP=933244655
validation succeeded for archived log
archived log file name=/opt/oracle/archive/db/1_1207_91233774.dbf RECID=1207 STAMP=933249510
validation succeeded for archived log
archived log file name=/opt/oracle/archive/db/1_1208_91233774.dbf RECID=1208 STAMP=933254500
validation succeeded for archived log
archived log file name=/opt/oracle/archive/db/1_1209_91233774.dbf RECID=1209 STAMP=933259445
validation succeeded for archived log

查看v$archived_log视图也没有旧归档日志记录

于是百度找到一篇文章http://3y.uu456.com/bp_3i90z4529l10ttd0odyk_1.html 大体意思是MAN删除归档日志的依据是controlfile中记录的归档日志，而不是你磁盘上实际存在的归档日志
，如果你的归档日志已经不在controlfile中就无法被RMAN识别到，也就无法被删除。而致于归档信息何时在控制文件中被覆盖，这由一个参数control_file_record_keep_time来控制。
查看数据库中的参数是默认的7天
SYS@db> show parameter CONTROL_FILE_RECORD_KEEP_TIME
?
NAME? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? TYPE? ? ? ? ? ? ? ? ? ? ? ? ? ? VALUE
------------------------------------ -------------------------------- ------------------------------
control_file_record_keep_time? ? ? ? integer? ? ? ? ? ? ? ? ? ? ? ? ? 7

难道是在控制文件中归档日志的记录条数只能保留7天的么？于是到MOS去找相关文档找到一篇Why Are Controlfile Entries For Archived Logs Not Overwritten After CONTROL_FILE_RECORD_KEEP_TIME? (文档 ID 1056085.1)，文档介绍CONTROL_FILE_RECORD_KEEP_TIME参数并不是强制在控制文件中保留多少天的归档日志条目，而是由V$CONTROLFILE_RECORD_SECTION视图中的ARCHIVED LOG条目去控制的，当RECORDS_TOTAL=RECORDS_USED时旧的归档日志就会被覆盖掉。
于是查数据库中的V$CONTROLFILE_RECORD_SECTION视图，看到ARCHIVED LOG行的records_total=224意味着控制文件中只能保留224条归档日志文件信息。
SYS@dbs> select * from v$controlfile_record_section where type='ARCHIVED LOG';
?
TYPE? ? ? ? ? ? ? ? ? ? ? ? RECORD_SIZE RECORDS_TOTAL RECORDS_USED FIRST_INDEX LAST_INDEX LAST_RECID
---------------------------- ----------- ------------- ------------ ----------- ---------- ----------
ARCHIVED LOG? ? ? ? ? ? ? ? ? ? ? ? 584? ? ? ? ? 224? ? ? ? ? 224? ? ? ? ? 88? ? ? ? 87? ? ? 1235