DataGuard apply比較慢

今天發現有一個 oracle 物理DataGuard apply比較慢，根據官方dg 優化文檔修改相關參數，
下面的方法有一點效果，不過不大。
一、修改並行度
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE PARALLEL 8 using current logfile disconnect from session;
二、修改消息大小
alter system Set PARALLEL_EXECUTION_MESSAGE_SIZE = 4096 scope=spfile;
三、取消block check
alter system set DB_BLOCK_CHECKSUM=false scope=spfile;
四、異步IO
alter system set disk_asynch_io=TRUE scope=spfile;
五、os異步傳輸
alter system set filesystemio_options=setall scope=spfile;
asynch:啓用異步I/O
directio:啓用同步I/O
setall:同時啓用異步和同步I/O
none:禁用異步和同步I/O
(ALTER DATABASE RECOVER managed standby database cancel)