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Flink Jira Bot updated FLINK-22611: ----------------------------------- Labels: auto-deprioritized-major (was: stale-major) Priority: Minor (was: Major) This issue was labeled "stale-major" 7 ago and has not received any updates so it is being deprioritized. If this ticket is actually Major, please raise the priority and ask a committer to assign you the issue or revive the public discussion. > add documentation about the semantics of timestamp for time window output > ------------------------------------------------------------------------- > > Key: FLINK-22611 > URL: https://issues.apache.org/jira/browse/FLINK-22611 > Project: Flink > Issue Type: Improvement > Reporter: Zhenhao Li > Priority: Minor > Labels: auto-deprioritized-major > > It seems that all windowed aggregation output receives the timestamp metadata > if event time is being used for the processing. > However, I couldn't find anything on the documentation pages about what > timestamp value each output gets. Intuitively, it makes sense to assume it is > the maximal timestamp from the input records of the window. > After digging in the source code, I got the impression that the timestamp of > the output is actually 1 millisecond before the window end time. > See > https://github.com/apache/flink/blob/99c2a415e9eeefafacf70762b6f54070f7911ceb/flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/windowing/EvictingWindowOperator.java#L375 > and > https://github.com/apache/flink/blob/99c2a415e9eeefafacf70762b6f54070f7911ceb/flink-streaming-java/src/main/java/org/apache/flink/streaming/api/windowing/windows/TimeWindow.java#L84 > Correct me if I'm wrong. If I'm right, I think we should add documentation > about it since this is very important because it is not uncommon to chain > multiple windowed processes. Understanding the timestamp semantics is > critical to the correctness of the code. -- This message was sent by Atlassian Jira (v8.3.4#803005)