如果Oracle控制文件是從備份中恢復的，下面就為您詳細介紹Oracle控制文件的恢復，供您參考，希望對您學習Oracle控制文件能有所幫助。
那麼數據庫在open過程中又將如何呢?
首先備份Oracle控制文件控制文件，打開數據庫，增進檢查點:
- [Oracle@jumper eygle]$ cp control01.ctl control01.ctl.bak
- [Oracle@jumper eygle]$ sqlplus "/ as sysdba"
- SQL*Plus: Release 9.2.0.4.0 - Production on Fri Aug 11 10:46:05 2006
- Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
- Connected to an idle instance.
- SQL> startup
- Oracle instance started.
- Total System Global Area 139531744 bytes
- Fixed Size 452064 bytes
- Variable Size 121634816 bytes
- Database Buffers 16777216 bytes
- Redo Buffers 667648 bytes
- Database mounted.
- Database opened.
- SQL> alter system checkpoint;
- System altered.
- SQL> shutdown immediate;
- Database closed.
- Database dismounted.
- Oracle instance shut down.
- SQL> exit
- Disconnected from Oracle9i Enterprise Edition Release 9.2.0.4.0 - Production
- With the Partitioning option
- JServer Release 9.2.0.4.0 - Production
然後恢復舊的控制文件，mount數據庫，轉儲數據文件頭:
- [Oracle@jumper eygle]$ mv control01.ctl control01.ctl.n
- [Oracle@jumper eygle]$ mv control01.ctl.bak control01.ctl
- [Oracle@jumper eygle]$ sqlplus "/ as sysdba"
- SQL*Plus: Release 9.2.0.4.0 - Production on Fri Aug 11 10:46:50 2006
- Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
- Connected to an idle instance.
- SQL> startup mount;
- Oracle instance started.
- Total System Global Area 139531744 bytes
- Fixed Size 452064 bytes
- Variable Size 121634816 bytes
- Database Buffers 16777216 bytes
- Redo Buffers 667648 bytes
- Database mounted.
- SQL> alter session set events 'immediate trace name file_hdrs level 10';
- Session altered.
- SQL> !
我們看Oracle控制文件控制文件的信息（選擇一個文件）:
- DATA FILE #4:
- (name #4) /opt/Oracle/oradata/eygle/eygle01.dbf
- creation size=0 block size=8192 status=0xe head=4 tail=4 dup=1
- tablespace 4, index=4 krfil=4 prev_file=0
- unrecoverable scn: 0x0000.00000000 01/01/1988 00:00:00
- Checkpoint cnt:61 scn: 0x0000.002acb1e 08/11/2006 10:44:38
- Stop scn: 0x0000.002acb1e 08/11/2006 10:44:38
- Creation Checkpointed at scn: 0x0000.0015078d 06/06/2006 09:41:54
再看數據文件頭信息:
- FILE HEADER:
- Software vsn=153092096=0x9200000, Compatibility Vsn=134217728=0x8000000
- Db ID=1407686520=0x53e79778, Db Name='EYGLE'
- Activation ID=0=0x0
- Control Seq=989=0x3dd, File size=1280=0x500
- File Number=4, Blksiz=8192, File Type=3 DATA
- Tablespace #4 - EYGLE rel_fn:4
- Creation at scn: 0x0000.0015078d 06/06/2006 09:41:54
- Backup taken at scn: 0x0000.00000000 01/01/1988 00:00:00 thread:0
- reset logs count:0x232bee1f scn: 0x0000.0007c781 recovered at 08/11/2006 10:11:26
- status:0x0 root dba:0x00000000 chkpt cnt: 64 ctl cnt:63
- begin-hot-backup file size: 0
- Checkpointed at scn: 0x0000.002acb98 08/11/2006 10:46:24
我們注意到數據文件的chkpt cnt: 64 要大約控制文件的Checkpoint cnt:61，也就是說控制文件是舊的。
此時嘗試打開數據庫就會出現如下錯誤:
- [Oracle@jumper udump]$ sqlplus "/ as sysdba"
- SQL*Plus: Release 9.2.0.4.0 - Production on Fri Aug 11 10:51:20 2006
- Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
- Connected to:
- Oracle9i Enterprise Edition Release 9.2.0.4.0 - Production
- With the Partitioning option
- JServer Release 9.2.0.4.0 - Production
- SQL> alter database open;
- alter database open
- *
- ERROR at line 1:
- ORA-01122: database file 1 failed verification check
- ORA-01110: data file 1: '/opt/Oracle/oradata/eygle/system01.dbf'
- ORA-01207: file is more recent than controlfile - old controlfile
Oracle告訴我們，控制文件是舊的。此時我們可以通過重建控制文件或者從舊的數據備份開始恢復。
