ORA-08189: 故障

时间点:time1
SQL> select dbms_flashback.get_system_change_number from dual;

GET_SYSTEM_CHANGE_NUMBER
------------------------
               152713033

 

SQL>  select count(*) from testvarchar;

  COUNT(*)
----------
  10000000

操作如下：

SQL> delete testvarchar;   

10000000 rows deleted.

SQL> commit;

Commit complete.

SQL> select count(*) from testvarchar;

  COUNT(*)
----------
         0

时间点：time2

SQL> select dbms_flashback.get_system_change_number from dual;

GET_SYSTEM_CHANGE_NUMBER
------------------------
               152883734

用Flashback功能查询以前的数据

 

SQL> select count(*) from testvarchar as of scn 152713033;

  COUNT(*)
----------
  10000000

SQL>

用flashback直接恢复表

SQL> flashback table testvarchar to scn 152713033;
flashback table testvarchar to scn 152713033
                *
ERROR at line 1:
ORA-08189: cannot flashback the table because row movement is not enabled

SQL> alter table testvarchar enable row movement;

Table altered.

 

这个命令的作用是，允许Oracle 修改分配给行的rowid。在Oracle 中，插入一行时就会为它分配一个rowid，而且这一行永远拥有这个rowid。闪回表处理会对EMP 完成DELETE，并且重新插入行，这样就会为这些行分配一个新的rowid。要支持闪回就必须允许Oracle 执行这个操作

 

SQL> flashback table testvarchar to scn 152713033;

Flashback complete.

SQL> select count(*) from testvarchar;

  COUNT(*)
----------
  10000000

SQL>

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