CRITICAL **: Couldn't acquire global lock, snapshots will not be consistent: Access denied

报错如下：
** (mydumper:56288): CRITICAL **: Couldn't acquire global lock, snapshots will not be consistent: Access denied; you need (at least one of) the RELOAD privilege(s) for this operation

解决办法：
RDS应在备库执行备份操作，主库上执行备份会有如上报错。