oracle归档日志的概念,浅谈Oracle归档日志

什么是归档日志

归档日志(Archive Log)是非活动的重做日志备份.通过使用归档日志,可以保留所有重做历史记录,当数据库处于ARCHIVELOG模式并进行日志切换式,后台进程ARCH会将重做日志的内容保存到归档日志中.当数据库出现介质失败时,使用数据文件备份,归档日志和重做日志可以完全恢复数据库。

如何开启归档模式

查询是否开启归档

[oracle@osc ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.4.0 Production on Mon Nov 12 17:36:13 2018

Copyright (c) 1982, 2013, Oracle. All rights reserved.

Connected to:

Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production

With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL> archive log list;

Database log mode No Archive Mode

Automatic archival Disabled

Archive destination USE_DB_RECOVERY_FILE_DEST

Oldest online log sequence 1124

Current log sequence 1126

由上可见,数据库未开启归档

开启归档模式

SQL> shutdown immediate;

Database closed.

Database dismount

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