物理standby database的日常维护

1.停止Standby

select process, status from v$managed_standby; --查看备库是否在应用日志进行恢复

alter database recover managed standby database cancel;
shutdown immediate;

2.切换到只读模式

-----由shutdown模式切换到只读模式-------

startup nomount;
alter database mount standby database;
alter database open read only;

-----由应用日志模式切换到只读模式-------

alter database recover managed standby database cancel;-- 取消日志应用
alter database open read only;

3.切换回管理恢复模式

startup nomount;
alter database mount standby database;
alter database recover managed standby database disconnect from session;-- 启动日志应用

alter database recover managed standby database using current logfile disconnect from session;

4.主库和备库之间角色切换

4.1 主库切换为备库
alter database commit to switchover to physical standby;

alter database commit to switchover to physical standby with session shutdown;-- 主库有会话连接的时候
shutdown immediate
startup nomount;
alter database mount standby database;
alter database recover managed standby database disconnect from session;

4.2 从库切换为主库

alter database commit to switchover to primary;
shutdown immediate;
startup
alter system switch logfile;

5.备库自动使用主库传过来的日志进行恢复

alter database recover automatic standby database;

6.更改保护模式

alter database set standby database to maximize protection;
alter database set standby database to maximize availability;
alter database set standby database to maximize performancen;

7.取消自动恢复模式

alter database recover managed standby database cancel;
alter database recover managed standby database finish;
alter database recover managed standby database finish force;

8.如何应用主库的部分日志没有传到从数据库中

查询$ARCHIVE_GAP出来有记录的话，也可以同样采用在复制到从数据库上然后在从数据库中注册这些日志，步骤如下：
a. 备库上检查是否存在归档中断
SQL> SELECT THREAD#, LOW_SEQUENCE#, HIGH_SEQUENCE# FROM V$ARCHIVE_GAP;
b. 在主库上执行语句并找出归档文件
SQL> SELECT NAME FROM V$ARCHIVED_LOG WHERE THREAD#=1 AND DEST_ID=1 AND SEQUENCE# BETWEEN XX AND XX;
c、如果存在拷贝相应的归档到STANDBY数据库，并注册.
SQL> ALTER DATABASE REGISTER PHYSICAL LOGFILE 'xxx';