oracle 18c 开始有个新特性，通过service name可以同步备库数据，对于丢失归档、少量差异甚至全库重新初始化都比较方便。

在备库上
rman target /
shutdown immediate;
startup mount;
recover standby database from service TNS_PRI;
exit
等一会就同步了，前提是dg之前配置都正确。

sqlplus / as sysdba
alter database recover managed standby database until consistent;
alter database open read only;
alter database recover managed standby database disconnect;
exit

打完收工。