Hi Ori, No. Flink does it differently. Operators that are keeping track of late events, are remembering the latest watermark. If a new element arrives with even time lower compared to the latest watermark, it is marked as a late event [1]
Piotrek [1] https://ci.apache.org/projects/flink/flink-docs-release-1.11/concepts/timely-stream-processing.html#lateness czw., 20 sie 2020 o 17:13 Ori Popowski <ori....@gmail.com> napisał(a): > In the documentation > <https://ci.apache.org/projects/flink/flink-docs-stable/dev/stream/operators/windows.html#allowed-lateness> > it states that: > > *[…], Flink keeps the state of windows until their allowed lateness > expires. Once this happens, Flink removes the window and deletes its state, > as also described in the Window Lifecycle > <https://ci.apache.org/projects/flink/flink-docs-stable/dev/stream/operators/windows.html#window-lifecycle> > section.* > > However, something doesn't make sense to me. > > If Flink deletes the window state, then how can it know that subsequent > events are late? i.e. if the state is deleted, then Flink has no way of > knowing than an event is late, because it can think it's just a new event, > unless it keeps track of which keyed windows are closed forever. > > Does Flink remember which keyed windows are closed forever? > > Thanks. >
