如何更改數據庫的SCN?

　　很多時候我們需要調整數據庫系統的SCN值有的是為了恢復的需要如為了解決ORA 錯誤

　　而以下修改純屬無聊:

　　通過oradebug修改SCN

　　[oracle@jumper oracle]$ sqlplus / as sysdba

　　SQL*Plus: Release Production on Wed Dec ::

　　Connected to:
Oraclei Enterprise Edition Release Production
With the Partitioning option
JServer Release Production

　　SQL> col a for
SQL> select CHECKPOINT_CHANGE# a from v$datafile;

　　SQL> oradebug setmypid
Statement processed
SQL> oradebug DUMPvar SGA kcsgscn_
kcslf kcsgscn_ [BC BC) = FF
B
SQL> oradebug poke xBC
BEFORE: [BC BC) =
AFTER: [BC BC) =

　　確認更改

　　SQL> select dbms_flashbackget_system_change_number a from dual;

　　SQL> oradebug DUMPvar SGA kcsgscn_
kcslf kcsgscn_ [BC BC) = FAC A
B
SQL>
SQL> alter system checkpoint;

　　System altered

　　SQL> select CHECKPOINT_CHANGE# a from v$datafile;

　　此時無法正常關閉數據庫

　　Oracle會檢測到異常:

　　SQL> shutdown immediate;
ORA: internal error code arguments: [kfhsls_] [] [] [] [] [] [] []

　　shutdown abort強制關閉數據庫

　　重新啟動會出現錯誤

　　SQL> shutdown abort;
ORACLE instance shut down
SQL> startup
ORACLE instance started

　　Total System Global Area bytes
Fixed Size                   bytes
Variable Size              bytes
Database Buffers           bytes
Redo Buffers                 bytes
Database mounted
ORA: internal error code arguments: [] [] [] [] [] [] [] []

　　通過不完全恢復啟動數據庫

　　SQL> recover database using backup controlfile until cancel;
ORA: change generated at // :: needed for thread
ORA: suggestion : /opt/oracle/oradata/conner/archive/_dbf
ORA: change for thread is in sequence #

　　Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
cancel
ORA: warning: RECOVER succeeded but OPEN RESETLOGS would get error below
ORA: file needs more recovery to be consistent
ORA: data file : /opt/oracle/oradata/conner/systemdbf

　　ORA: media recovery not started

　　SQL> alter database open resetlogs;

　　Database altered

　　此時數據庫可以正常打開

From:http://tw.wingwit.com/Article/program/Oracle/201311/17746.html