oracle dataguard 从库 MRP 进程的状态是 WAIT_FOR_GAP

因主库归档日志未备份直接删除后，从库不能更新，19c版本以上，之前未打补丁，使用

RECOVER STANDBY DATABASE FROM SERVICE PRM180;之后，在执行

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

alter database recover managed standby database cancel;  
alter database open;

打不开提示

SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-10458: standby database requires recovery
ORA-01152: file 1 was not restored from a sufficiently old backup
ORA-01110: data file 1: '/u02/oradata/system01.dbf'

后来打了19c的最新的补丁，

rman target /

RMAN> RECOVER STANDBY DATABASE FROM SERVICE PRM180;

之后，直接在在sql命令中输入： 

alter database open；打开正常

SQL> alter database open;Database altered.

参考：用一条命令将RMAN增量备份前滚到物理备库 (文档 ID 2504977.1)