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ASF GitHub Bot commented on FLINK-6007: --------------------------------------- Github user kl0u commented on a diff in the pull request: https://github.com/apache/flink/pull/3514#discussion_r105649773 --- Diff: flink-streaming-java/src/main/java/org/apache/flink/streaming/api/operators/InternalWatermarkCallbackService.java --- @@ -58,7 +59,17 @@ * An array of sets of keys keeping the registered keys split * by the key-group they belong to. Each key-group has one set. */ - private final Set<K>[] keysByKeygroup; + private final Set<K>[] registeredKeysByKeyGroup; + + /** + * An array of sets of keys keeping the keys "to delete" split + * by the key-group they belong to. Each key-group has one set. + * <p> --- End diff -- Fixed this. > ConcurrentModificationException in WatermarkCallbackService > ----------------------------------------------------------- > > Key: FLINK-6007 > URL: https://issues.apache.org/jira/browse/FLINK-6007 > Project: Flink > Issue Type: Bug > Components: DataStream API > Affects Versions: 1.3.0 > Reporter: Kostas Kloudas > Assignee: Kostas Kloudas > Priority: Blocker > Fix For: 1.3.0 > > > Currently, if an attempt is made to call > {{InternalWatermarkCallbackService.unregisterKeyFromWatermarkCallback()}} > from within the {{OnWatermarkCallback}}, a > {{ConcurrentModificationException}} is thrown. The reason is that the > {{invokeOnWatermarkCallback}} iterates over the list of keys and calls the > callback for each one of them. > To fix this, the deleted keys are put into a separate list, and the deletion > happens after the iteration over all keys has finished. -- This message was sent by Atlassian JIRA (v6.3.15#6346)