dg主备切换

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; 切换后数据库会自动关闭
startup;
alter database recover managed standby database using current logfile disconnect from session;
2.从库切换为主库
alter database commit to switchover to primary; 切换后数据库到mount
alter database open;
alter system switch logfile;
3.检查切换状态
select open_mode,switchover_status,database_role from v$database;


备注：
1.备库切换为主库时提示alter database commit to switchover to primary;
ORA-16139: media recovery required
解决：备库开启日志应用
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;
2.备库切换为主库时，switchover status 状态为failed_destination
原因：备库监听有问题，重启备库监听,再查状态就变成to_standby
解决：lsnrctl start