Oracle ADG Broker主备切换报错失败处理

切换假失败：ORA-16847和ORA-16816

通过DG Broker发起主备切换：

DGMGRL> show configuration

Configuration - dg_msgdb

  Protection Mode: MaxPerformance
  Members:
  msgdb_1 - Primary database
    msgdb_0 - Physical standby database 

Fast-Start Failover:  Disabled

Configuration Status:
SUCCESS   (status updated 48 seconds ago)

DGMGRL> switchover to msgdb_0
Performing switchover NOW, please wait...
Error: ORA-1034: ORACLE not available
Error: ORA-16625: cannot reac