[ https://issues.apache.org/jira/browse/FLINK-16039?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17067332#comment-17067332 ]
Manas Kale edited comment on FLINK-16039 at 3/26/20, 3:49 AM: -------------------------------------------------------------- Hi all, I've started a discussion on the mailing archive [here][[https://lists.apache.org/thread.html/rf44c033e20d165105a3adf1d36c1e3857231e7266aa844d4fc4b6e1f%40%3Cdev.flink.apache.org%3E]]. was (Author: manas96): Hi all, I've started a discussion on the mailing archive [here|[https://lists.apache.org/thread.html/rf44c033e20d165105a3adf1d36c1e3857231e7266aa844d4fc4b6e1f%40%3Cdev.flink.apache.org%3E]]. > [Discuss] Add API method to get last element in session window > -------------------------------------------------------------- > > Key: FLINK-16039 > URL: https://issues.apache.org/jira/browse/FLINK-16039 > Project: Flink > Issue Type: Improvement > Components: API / DataStream > Affects Versions: 1.10.0 > Reporter: Manas Kale > Priority: Minor > > Consider the events : > [1, event], [2, event] > where first element is event timestamp in seconds and second element is event > code/name. > Also consider that an Event time session window with inactivityGap = 2 > seconds is acting on above stream. > When the first event arrives, a session window should be created that is > [1,1]. > When the second event arrives, a new session window should be created that is > [2,2]. Since this falls within firstWindowTimestamp+inactivityGap, it should > be merged into session window [1,2] and [2,2] should be deleted. > This is my understanding of how session windows are created. *Please correct > me if wrong.* > However, Flink does not follow such a definition of windows semantically. If > I call the getEnd() method of the TimeWindow() class, I get back _timestamp > + inactivityGap_. > For the above example, after processing the first element, I would get 1 + 2 > = 3 seconds as the window "end". > The actual window end should be the timestamp 1, which is the last event in > the session window. > A solution would be to change the "end" definition of all windows, but I > suppose this would be breaking and would need some debate. > Therefore, I propose an intermediate solution : add a new API method that > keeps track of the last element added in the session window. > If there is agreement on this, I would like to start drafting a change > document and implement this. -- This message was sent by Atlassian Jira (v8.3.4#803005)