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https://issues.apache.org/jira/browse/FLINK-5972?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15934701#comment-15934701
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ASF GitHub Bot commented on FLINK-5972:
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GitHub user aljoscha opened a pull request:
https://github.com/apache/flink/pull/3587
[FLINK-5972] Don't allow shrinking merging windows
Thanks for contributing to Apache Flink. Before you open your pull request,
please take the following check list into consideration.
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You can merge this pull request into a Git repository by running:
$ git pull https://github.com/aljoscha/flink
jira-5972-disallow-shrinking-windows
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/flink/pull/3587.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 #3587
----
commit d6de53c286db4386166c50c6a3f5871f2b6ed43f
Author: Aljoscha Krettek <[email protected]>
Date: 2017-03-21T13:58:45Z
[FLINK-5972] Don't allow shrinking merging windows
commit 197f1f95e74fe7557eaead168c88c5b0d8ea2932
Author: Aljoscha Krettek <[email protected]>
Date: 2017-03-21T14:00:24Z
[hotfix] Add EvictingWindowOperatorContractTest
This also patches in the missing side output support for
EvictingWindowOperator.
----
> 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
>
>
> 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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