Oracle 12c SCN推进方法汇总（四）之修改控制文件

查看当前SCN

SQL> ALTER SYSTEM CHECKPOINT ;

System altered.

SQL> select current_scn from v$database;

CURRENT_SCN
-----------
   20101799

SQL> select to_char(20101799,'xxxxxxxxx')from dual;

TO_CHAR(20
----------
   132baa5
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copy 控制文件

[oracle@devin-enmo controlfile]$ sz control01.ctl 
rz
Starting zmodem transfer.  Press Ctrl+C to cancel.
Transferring control01.ctl...
  100%   10768 KB    10768 KB/sec    00:00:01       0 Errors  
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当前SCN约2000W，将132baa5改成232baa5，换算出来大概是3700W

SQL> SELECT TO_NUMBER('232BAA7','XXXXXXXXXXXXXXXX') FROM DUAL;

TO_NUMBER('232BAA7','XXXXXXXXXXXXXXXX')
---------------------------------------
                               36879015
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用UE修改控制文件

通过132baa5定位当前scn所在的块为00048000H，偏移量为60的行的第9个字节开始到12个字节之间；flag为该块第一行偏移量为15的0x04;checksum为该块第二行的offset 16，17的0x5a9d

将01改成02，并将checksum以及flag清0

重新上传控制文件

[oracle@devin-enmo controlfile]$ rz
rz waiting to receive.
Starting zmodem transfer.  Press Ctrl+C to cancel.
Transferring control01.ctl...
  100%   10768 KB    10768 KB/sec    00:00:01       0 Errors  

[oracle@devin-enmo controlfile]$ cp control01.ctl ../datafile/control02.ctl
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启动数据库，验证

[oracle@devin-enmo controlfile]$ sqlplus / as sysdba

SQL*Plus: Release 12.2.0.1.0 Production on Mon Feb 1 15:50:50 2021

Copyright (c) 1982, 2016, Oracle.  All rights reserved.


Connected to:
Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production

SQL> startup nomount  
ORACLE instance started.

Total System Global Area  268435456 bytes
Fixed Size                  8619496 bytes
Variable Size             201329176 bytes
Database Buffers           50331648 bytes
Redo Buffers                8155136 bytes

SQL> alter database mount ;

Database altered.

SQL>  select checkpoint_change# from v$database;

CHECKPOINT_CHANGE#
------------------
          36879013

SQL> alter database open;

Database altered.

SQL> select current_scn from v$database;

CURRENT_SCN
-----------
   36979499
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确认修改成功。