Data engineering·Time and correctness in streams
the dashboard shows a partial count that keeps rising, because the window emits early every ten seconds before it finally closes.
Window trigger
Also calledemit policy, trigger
The rule that decides when a window produces output — on watermark, early on a timer or a count, or late when more data arrives. Separating it from the window definition is what lets you have both a fast approximate answer and a correct final one from the same job. Whoever consumes the output has to know which they are looking at, since an early fire and a final fire are indistinguishable unless you label them.