How to check the number of DMLs performed by the refresh in oracle RAC database

We always use table X$KNSTMVR to check the number of DMLs performed by the refresh in oracle database .

But in the RAC enviornment, the data on  X$KNSTMVR only have the data for it's own instance.

How can I check the golbal information of  X$KNSTMVR ?

Another question is for view GV$MVREFRESH, when I query GV$MVREFRESH on one instance, it will show the data for all the instance. but when I run the query on VIEW_DEFINITION for this view, it only show the data for current instance. Why?

SQL> select * from gv$mvrefresh;

   INST_ID        SID    SERIAL# CURRMVOWNER                     CURRMVNAME