常用命令


1.查询命令

  1. 1. select name,db_unique_name from v$database;
  2. 2. select max(sequence#) from v$archived_log;

查询保护模式

select protection_mode,database_role,open_mode from v$database;

查询最近5个应用的归档

select * from (select name,recid,sequence#,status,applied from v$archived_log  order by recid desc) where rownum<5;

查询归档日志号及

select sequence#,status,thread#,block#,process,status from v$managed_standby;

2.日志应用
打开日志应用及取消日志应用语句：

1. alter database recover managed standby database using current logfile disconnect from session;
2. alter database recover managed standby database disconnect from session;
3. alter database recover managed standby database cancel;


3.停止Standby

1. select process, status from v$managed_standby; --查看备库是否在应用日志进行恢复
2. alter database recover managed standby database cancel;
3. shutdown immediate;


4.切换到只读模式
——-由shutdown模式切换到只读模式———-

1. startup nomount;
2. alter database mount standby database;
3. alter database open read only;

——-由应用日志模式切换到只读模式———-

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


5.切换回管理恢复模式

1. startup nomount;
2. alter database mount standby database;
3. alter database recover managed standby database disconnect from session; -- 启动日志应用
4. alter database recover managed standby database using current logfile disconnect from session;


6.主库和备库之间角色切换
6.1 主库切换为备库

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


6.2 从库切换为主库

1. alter database commit to switchover to primary;
2. shutdown immediate;
3. startup
4. alter system switch logfile;


7.备库自动使用主库传过来的日志进行恢复

alter database recover automatic standby database;


8.更改保护模式

1. alter database set standby database to maximize protection;
2. alter database set standby database to maximize availability;
3. alter database set standby database to maximize performancen;


9.取消自动恢复模式

1. alter database recover managed standby database cancel;
2. alter database recover managed standby database finish;
3. alter database recover managed standby database finish force;


启动/关闭顺序

启动顺序
针对DataGuard采用不同的模式,主备库的启动顺序如下:

  1. max performance(最大性能):主库,备库的启动和关闭顺序没有先后
  2. max availability(最大可用): 要先启动备库,再启动主库,如果启动顺序相反,主库仍然能启动,但会在主库的alert.log文件中出现如下出错提示
  3. max protection(最大保护): 先启动备库,再启动主库,如果顺序相反,主库实例会自动中断,数据库无法启动,并会在alert.log文件中留下如下的信息

关闭顺序

  • 关库时，先关主库，再关备库