ORACLE DataGuard 主备库角色切换

千家信息网最后更新 2025年01月24日ORACLE DataGuard 主备库角色切换主备库切换原因： 1. switch：用户主动切换； 2. failover：主库出现故障，强行切换； switch切换过程：先主库再备库 主库 1. 查看switchover_status：select database_role, switchover_status from v$database; 如果switchover_status为：to standby 则： ALTER DATABASE COMMIT TO SWITCHOVER TO PHYSICAL STANDBY 否则用：ALTER DATABASE COMMIT TO SWITCHOVER TO PHYSICAL STANDBY WITH SESSION SHUTDOWN; 2. 重启数据库： shutdown immediate; startup nomount; 3. 以备库mount alter database mount standby database; 备库 1. 应用redo：alter database recover managed standby database disconnect from session; 2. 查看switchover_status：select database_role, switchover_status from v$database; 如果switchover_status为：to primary 则：ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY 否则用：ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY WITH SESSION SHUTDOWN; 3. 重启数据库 shutdown immediate; startup; failover 主备库切换 1.. 停止日志应用
alter database recover managed standby database cancel;
2. 关闭standby日志传输
alter database recover managed standby database finish force;
3. 切换到primary
alter database commit to switchover to primary with session shutdown; 做这一步的时候，若存在gap，则会报ORA-16139:Switchover: Media recovery required - standby not in limbo 错误。 做测试的时候，若先起主库再起备库，且未等待备库相关日志传输完毕，就会出现这个问题。此时需要强制切换
alter database activate physical standby database; 4. 重启数据库到open状态