Looking over the code, I see that Flink creates a TimeWindow object each time the WindowAssigner is created. I have not yet tested this, but I am wondering if this can become problematic if you have a very long sliding window with a small slide, such as a 24 hour window with a 1 minute slide. It seems this would create 1,440 TimeWindow objects per event. Event a low event rates this would seem to result in an explosion of TimeWindow objects: at 1,000 events per second, you'd be creating 1,440,000 TImeWindow objects. After 24 hours you'd have nearly 125 billion TM objects that would just begin to be purged.
Does this analysis seem right? I suppose that means you should not use long length sliding window with small slides.
