"ram to cache the distinct data about sliding window" means I used computer momery not the third part db to cache the data need used in window.
“the data need used in window” means ：such as the sliding window is 1 hour, and I need to count the distinct users, I need to cache the user id about one hour.
Cause there’re no related errors.
I used flink window, and when the job begins, we could get the results of windiow.But there’re no results issued after a few hours.
I found the job is still running and no errors, and the data not used window all can be issued.
By the way, I used Flink 1.3.2 and ram to cache the distinct data about sliding window.