从18c开始新引入了一个视图V$DATAGUARD_PROCESS用于查看DG的进程状态信息，取代了v$managed_standby视图。
如：

SQL> select name,type,role,action,group# from V$DATAGUARD_PROCESS;

NAME  TYP ROLE                     ACTION           GROUP#
----- --- ------------------------ ------------ ----------
LGWR  KSB log writer               IDLE                  0
TMON  KSB redo transport monitor   IDLE                  0
TT00  KSV gap manager              IDLE                  0
TT01  KSV redo transport timer     IDLE                  0
ARC0  KSB archive local            IDLE                  0
ARC1  KSB archive redo             IDLE                  0
ARC2  KSB archive redo             IDLE                  0
ARC3  KSB archive redo             IDLE                  0
rfs   NET RFS ping                 IDLE                  0
rfs   NET RFS sync                 IDLE                  4
rfs   NET RFS archive              IDLE                  0

NAME  TYP ROLE                     ACTION           GROUP#
----- --- ------------------------ ------------ ----------
MRP0  KSB managed recovery         APPLYING_LOG          0

12 rows selected.