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Oriol Orellana commented on FLINK-5717: --------------------------------------- [~aljoscha] Should I fix it and create a PR to master? > NPE on SessionWindows with ContinuousProcessingTimeTrigger > ---------------------------------------------------------- > > Key: FLINK-5717 > URL: https://issues.apache.org/jira/browse/FLINK-5717 > Project: Flink > Issue Type: Bug > Components: DataStream API > Affects Versions: 1.2.0, 1.1.4 > Reporter: Oriol Orellana > > The same bug as https://issues.apache.org/jira/browse/FLINK-4862, but for > ContinuousProcessingTimeTrigger. I copied the description from that same > issue. > *what's the error?* > The following NPE error is thrown when SessionWindows with > ContinuousProcessingTimeTrigger is used. > {code:borderStyle=solid} > Caused by: java.lang.NullPointerException > at > org.apache.flink.streaming.api.windowing.triggers.ContinuousProcessingTimeTrigger.clear(ContinuousProcessingTimeTrigger.java:91) > at > org.apache.flink.streaming.runtime.operators.windowing.WindowOperator$Context.clear(WindowOperator.java:768) > at > org.apache.flink.streaming.runtime.operators.windowing.WindowOperator$2.merge(WindowOperator.java:310) > at > org.apache.flink.streaming.runtime.operators.windowing.WindowOperator$2.merge(WindowOperator.java:297) > at > org.apache.flink.streaming.runtime.operators.windowing.MergingWindowSet.addWindow(MergingWindowSet.java:196) > at > org.apache.flink.streaming.runtime.operators.windowing.WindowOperator.processElement(WindowOperator.java:297) > at > org.apache.flink.streaming.runtime.io.StreamInputProcessor.processInput(StreamInputProcessor.java:183) > at > org.apache.flink.streaming.runtime.tasks.OneInputStreamTask.run(OneInputStreamTask.java:66) > at > org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:271) > at org.apache.flink.runtime.taskmanager.Task.run(Task.java:609) > at java.lang.Thread.run(Thread.java:745) > {code} > *how to reproduce ?* > use ContinuousProcessingTimeTrigger instead of the default EventTimeTrigger > in SessionWindowing example. > *what's the cause ?* > When two session windows are being merged, the states of the two > ContinuousProcessingTimeTrigger are merged as well and the new namespace is > the merged window. Later when the context tries to delete Timer from the old > trigger and looks up the timestamp by the old namespace, null value is > returned. -- This message was sent by Atlassian JIRA (v6.3.15#6346)