Configuring Flashback Database
如何查看數據庫是否處於歸檔模式？
mount database之后，執行如下命令
SQL> select log_mode from v$database; LOG_MODE ------------ ARCHIVELOG
conn as sysdba后，執行如下命令:
SQL> archive log list; Database log mode Archive Mode Automatic archival Enabled Archive destination USE_DB_RECOVERY_FILE_DEST Oldest online log sequence 202 Next log sequence to archive 204 Current log sequence 204
歸檔的實質，就是歸日志歷史的檔. (如何實現手工日志切換alter system switch logfile;)
SQL> show parameter recover NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ db_recovery_file_dest string /RealData/flash_recovery_area db_recovery_file_dest_size big integer 10G recovery_parallelism integer 0
啟用數據庫歸檔步驟
1、關閉數據庫
shutdown
2、mount 數據庫(mount起來之后，是可以修改數據庫的控制文件的；)
startup mount
3、修改歸檔模式
alter database archivelog;
4、打開數據庫
alter database open;
配置flashback database的條件
1、數據庫必須啟用歸檔模式
2、數據庫必須啟用閃回模式
3、閃回寫進程后台進程(fvwr)必須啟動
配置數據庫歸檔的步驟
條件
1、配置后台歸檔進程
log_archive_staret=true
log_archive_dest_1=
log_archive_format=
2、啟用數據庫歸檔
如何查看數據庫的閃回模式
v$database試圖的數據內容，是源自於oracle database 的控制文件中獲取的.因此查詢數據庫的閃回模式，可以通過查詢v$databse中獲取.
FLASHBACK_ON=ON不表示數據庫
SQL> select flashback_on from v$database; FLASHBACK_ON ------------------ NO
啟用數據庫閃回步驟
1、關閉數據庫
shutdown
2、mount數據庫
startup mount;
3、啟用模式
alter database flashback on;
4、打開數據庫
alter database open;
[oracle@arcerzhang DATACENTER]$ sqlplus /nolog SQL*Plus: Release 11.2.0.1.0 Production on Wed May 15 16:29:10 2013 Copyright (c) 1982, 2009, Oracle. All rights reserved. SQL> conn /as sysdba Connected to an idle instance. SQL> startup mount ORACLE instance started. Total System Global Area 3256942592 bytes Fixed Size 2217752 bytes Variable Size 1845496040 bytes Database Buffers 1392508928 bytes Redo Buffers 16719872 bytes Database mounted. SQL> select flashback_on from v$database; FLASHBACK_ON ------------------ NO SQL> alter database flashback on; Database altered. SQL> alter database open; Database altered. SQL> select flashback_on from v$database; FLASHBACK_ON ------------------ YES SQL> shutdown immediate Database closed. Database dismounted. ORACLE instance shut down. SQL> startup mount ORACLE instance started. Total System Global Area 3256942592 bytes Fixed Size 2217752 bytes Variable Size 1845496040 bytes Database Buffers 1392508928 bytes Redo Buffers 16719872 bytes Database mounted. SQL> select flashback_on from v$database; FLASHBACK_ON ------------------ YES
配置閃回寫進程后台進程(fvwr)的步驟
1、配置閃回日志目錄
2、配置閃回日志保存時間
DB_FLASHBACK_RETENTION_TARGET