In Stream Processing, what’s the difference between a count-based (aka tuple-based) window and a tumbling window?
From my perspective, they are the same:
The tumbling window sets its new (start,end)-pointers, each time a certain number of elements has arrived (it is a sliding window with size=slide). And this is also what the count-based window does.
can someone explain the difference to me?
A count window is sized by the number of event that are inside of it. A count window does not have any specific amount of time that it is going to be valid.
A tumbling window has fixed timespan and will create a new windows of data based on the timespan it is configured with. Any events that fall into that timespan will be used in the aggregates functions of the window.
Using Event Windows
It takes a little digging to find this link but it paints a very clear picture of the window types with graphical timelines to illustrate how data behaves inside each.
Windows in StreamInsight: The Basics
This page has a solid graphical example of what it means to be a tumbling window.