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https://issues.apache.org/jira/browse/FLINK-5972?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15936954#comment-15936954
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ASF GitHub Bot commented on FLINK-5972:
---------------------------------------
Github user tzulitai commented on a diff in the pull request:
https://github.com/apache/flink/pull/3587#discussion_r107506662
--- Diff:
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/windowing/EvictingWindowOperator.java
---
@@ -122,6 +121,19 @@ public void processElement(StreamRecord<IN> element)
throws Exception {
public void merge(W
mergeResult,
Collection<W> mergedWindows, W stateWindowResult,
Collection<W> mergedStateWindows) throws Exception {
+
+ if
((windowAssigner.isEventTime() && mergeResult.maxTimestamp() + allowedLateness
<= internalTimerService.currentWatermark())) {
--- End diff --
Ah, I see. Good seeing the tests at work catching this :-D
> Don't allow shrinking merging windows
> -------------------------------------
>
> Key: FLINK-5972
> URL: https://issues.apache.org/jira/browse/FLINK-5972
> Project: Flink
> Issue Type: Bug
> Components: DataStream API
> Affects Versions: 1.1.0, 1.2.0, 1.3.0
> Reporter: Aljoscha Krettek
> Priority: Blocker
> Fix For: 1.3.0, 1.2.1
>
>
> A misbehaving {{MergingWindowAssigner}} can cause a merge that results in a
> window that is smaller than the span of all the merged windows. This, in
> itself is not problematic. It becomes problematic when the end timestamp of a
> window that was not late before merging is now earlier than the watermark
> (the timestamp is smaller than the watermark).
> There are two choices:
> - immediately process the window
> - drop the window
> processing the window will lead to late data downstream.
> The current behaviour is to silently drop the window but that logic has a
> bug: we only remove the dropped window from the {{MergingWindowSet}} but we
> don't properly clean up state and timers that the window still (possibly)
> has. We should fix this bug in the process of resolving this issue.
> We should either just fix the bug and still silently drop windows or add a
> check and throw an exception when the end timestamp falls below the watermark.
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