Use "Once" to manage master "getRecords" go routine
Created by: typhoonzero
As mentioned by @helinwang in https://github.com/PaddlePaddle/Paddle/pull/2948#discussion_r128823462 use Once may be better to manage the getRecords go routine.
Created by: typhoonzero
As mentioned by @helinwang in https://github.com/PaddlePaddle/Paddle/pull/2948#discussion_r128823462 use Once may be better to manage the getRecords go routine.