開啟 oracle 的閃回功能

查看是否開啟閃回

SQL> select flashback_on from v$database;

FLASHBACK_ON
------------------
NO

查看是否配置了db_recover_file_dest

SQL> show parameter db_recovery

NAME				     TYPE	 VALUE
------------------------------------ ----------- ------------------------------
db_recovery_file_dest		     string
db_recovery_file_dest_size	     big integer 0

沒有配置的話，先創建對應的目錄，注意目錄的權限和oracle數據庫的一致

mkdir /u01/flashback
chown oracle:oinstall /u01/flashback

SQL> alter system set db_recovery_file_dest_size=30G scope=both;
SQL> alter system set db_recovery_file_dest='/u01/flashback'  scope=both;

System altered.

關閉 oracle

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.

啟動到 mount 狀態

SQL> startup mount;
ORACLE instance started.

Total System Global Area 1603411968 bytes
Fixed Size		    2253664 bytes
Variable Size		  905972896 bytes
Database Buffers	  687865856 bytes
Redo Buffers		    7319552 bytes
Database mounted.

開啟 archeve log

SQL> alter database archivelog;

Database altered.

開啟閃回功能

SQL> alter database flashback on;

Database altered.

啟動數據庫到 open 狀態

SQL> alter database open;

Database altered.

SQL> select flashback_on from v$database;

FLASHBACK_ON
------------------
YES