备份的控制文件和新的数据文件
2024-07-21 02:32:53
供稿：网友
我们可以想象，假如控制文件是从备份中恢复的，那么数据库在open过程中又将如何呢?首先备份控制文件，打开数据库，增进检查点: [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 2006Copyright (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然后恢复旧的控制文件，mount数据库，转储数据文件头:[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 2006Copyright (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> !我们看控制文件的信息（选择一个文件）: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
再看数据文件头信息: 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我们注重到数据文件的chkpt cnt: 64 要大约控制文件的Checkpoint cnt:61，也就是说控制文件是旧的。此时尝试打开数据库就会出现如下错误:[oracle@jumper udump]$ sqlplus "/ as sysdba"SQL*Plus: Release 9.2.0.4.0 - Production on Fri Aug 11 10:51:20 2006Copyright (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 - ProductionSQL> 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 controlfileOracle告诉我们，控制文件是旧的。此时我们可以通过重建控制文件或者从旧的数据备份开始恢复。
