检查
select name,open_mode,database_role,cdb from v$database;
select name,open_mode,con_id,dbid from v$containers;
!ps -ef | grep mrp
show con_name
show parameters db_unique_name;
SELECT SEQUENCE#, FIRST_TIME, NEXT_TIME FROM V$ARCHIVED_LOG ORDER BY SEQUENCE#;

alter system switch logfile;
select max(sequence#) from v$archived_log where archived='YES';

select * from v$logfile;
SELECT SEQUENCE#, FIRST_TIME, NEXT_TIME FROM V$ARCHIVED_LOG ORDER BY SEQUENCE#;

（一）Active DataGuard启动顺序
（1）启动监听，先启从库再起主库
lsnrctl start

（2）启动数据库，先启动备库在启主库

--先启备库

sql>startup
alter database recover managed standby database disconnect from session;

        
--再启主库
sql>startup

（二）DataGuard关闭顺序

（1）先关主库数据库：

sql>shutdown immediate；

（2）再关备用库：
sql>alter database recover managed standby database cancel;
sql>shutdown immediate;