oracle数据库切换DG步骤

备注：应用服务要先停止对外服务

1.先将主库切换成备库，然后将原主库启动到物理库的状态

SQL> Alter database commit to switchover to physical standby with session shutdown;

2.关闭主库

SQL> shutdown immediate;

3.打开数据库nomount

SQL> startup nomount;

4.更改主库为备库

SQL> alter database mount standby database;
SQL> alter database recover managed standby database disconnect from session;

如果配置了 standby redo log 并需要启用实时同步则执行以下代码

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

5.将备库切换成主库

SQL> select switchover_status from v$database;
SQL> select * from v$version where rownum<2;
SQL> alter database commit to switchover to primary with session shutdown;

如果备库还有未应用的日志则执行

SQL>alter database recover managed standby database disconnect from session;
SQL> shutdown immediate;
SQL> startup;

切换日志进行检查

SQL> select max(sequence#) from v$log;
SQL>select sequence#,applied from v$archived_log;
SQL> alter system switch logfile;