Github user zentol commented on a diff in the pull request:
https://github.com/apache/flink/pull/6076#discussion_r194702106
--- Diff: docs/dev/event_time.md ---
@@ -213,10 +213,36 @@ arrive after the system's event time clock (as
signaled by the watermarks) has a
timestamp. See [Allowed Lateness]({{ site.baseurl
}}/dev/stream/operators/windows.html#allowed-lateness) for more information on
how to work
with late elements in event time windows.
+## Idling sources
+
+Currently with pure event time watermarks generators, watermarks can not
progress if there are no elements
+to be processed. That means in case of gap in the incoming data, even time
will not progress and for
--- End diff --
typo: event time
---
