情景：利用Dataguard滚动方式升级数据库后，备库应用redo报错：ORA-10485
MRP0: Background Media Recovery terminated with error 10485
Errors in file /home/u01/app/diag/rdbms/orcl11g/ORCL/trace/ORCL_pr00_1644.trc:
ORA-10485: Real-Time Query cannot be enabled while applying migration redo.
Managed Standby Recovery not using Real Time Apply
Recovery interrupted!
MRP0: Background Media Recovery process shutdown (ORCL)
[oracle@app scripts]$ oerr ora 10485
10485, 00000, "Real-Time Query cannot be enabled while applying migration redo."
// *Cause: The Real-Time Query feature was enabled when an attempt was made
// to recover through migration redo generated during primary upgrades or
// downgrades.
// *Action: Close the standby database in order to recover through
// migration redo. Reenable the Real-Time Query feature afterwards.
原因：在应用migration redo的时候不能开启实时查询(即，在主库进行升级时候，备库不能开启实时查询）
解决方法：
shutdown immediate;
startup mount;
alter database recover managed standby database disconnect from session;
--待migration redo 相关的日志应用了后再开启实时apply
alter database recover managed standby database cancel;
alter database open;
alter database recover managed standby database using current logfile disconnect from session;