Configuring Flashback Database
如何查看数据库是否处于归档模式？
mount database之后，执行如下命令
SQL> select log_mode from v$database; LOG_MODE ------------ ARCHIVELOG
conn as sysdba后，执行如下命令:
SQL> archive log list; Database log mode Archive Mode Automatic archival Enabled Archive destination USE_DB_RECOVERY_FILE_DEST Oldest online log sequence 202 Next log sequence to archive 204 Current log sequence 204
归档的实质，就是归日志历史的档. (如何实现手工日志切换alter system switch logfile;)
SQL> show parameter recover NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ db_recovery_file_dest string /RealData/flash_recovery_area db_recovery_file_dest_size big integer 10G recovery_parallelism integer 0
启用数据库归档步骤
1、关闭数据库
shutdown
2、mount 数据库(mount起来之后，是可以修改数据库的控制文件的；)
startup mount
3、修改归档模式
alter database archivelog;
4、打开数据库
alter database open;
配置flashback database的条件
1、数据库必须启用归档模式
2、数据库必须启用闪回模式
3、闪回写进程后台进程(fvwr)必须启动
配置数据库归档的步骤
条件
1、配置后台归档进程
log_archive_staret=true
log_archive_dest_1=
log_archive_format=
2、启用数据库归档
如何查看数据库的闪回模式
v$database试图的数据内容，是源自于oracle database 的控制文件中获取的.因此查询数据库的闪回模式，可以通过查询v$databse中获取.
FLASHBACK_ON=ON不表示数据库
SQL> select flashback_on from v$database; FLASHBACK_ON ------------------ NO
启用数据库闪回步骤
1、关闭数据库
shutdown
2、mount数据库
startup mount;
3、启用模式
alter database flashback on;
4、打开数据库
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
配置闪回写进程后台进程(fvwr)的步骤
1、配置闪回日志目录
2、配置闪回日志保存时间
DB_FLASHBACK_RETENTION_TARGET