GitHub user aljoscha opened a pull request: https://github.com/apache/flink/pull/6348
[FLINK-9857] Delay firing of processing-time timers by 1 ms Description from Jira issue: ``` The firing of processing-time timers is off by one. This leads to problems in edge cases, as discovered here (mailing list) when elements arrive at the timestamp that is the end of the window. The problem is here (github). For event-time, we fire timers when the watermark is >= the timestamp, this is correct because a watermark T says that we will not see elements with a timestamp smaller or equal to T. For processing time, a time of T does not say that we won't see an element with timestamp T, which makes processing-time timers fire one ms too early. I think we can fix it by turning that <= into a <. ``` I'm afraid there are no tests for this behaviour and there can't be tests for the new behaviour since we're dealing with processing time here. R: @StephanEwen You can merge this pull request into a Git repository by running: $ git pull https://github.com/aljoscha/flink jira-9857-fix-system-processing-service Alternatively you can review and apply these changes as the patch at: https://github.com/apache/flink/pull/6348.patch To close this pull request, make a commit to your master/trunk branch with (at least) the following in the commit message: This closes #6348 ---- commit 914e9cf41b46bb4457b37ee789d3239a11740ee7 Author: Aljoscha Krettek <aljoscha.krettek@...> Date: 2018-07-16T13:58:07Z [FLINK-9857] Delay firing of processing-time timers by 1 ms ---- ---