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https://issues.apache.org/jira/browse/FLINK-6205?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15947394#comment-15947394
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ASF GitHub Bot commented on FLINK-6205:
---------------------------------------
GitHub user kl0u opened a pull request:
https://github.com/apache/flink/pull/3644
[FLINK-6205] [FLINK-6069] [cep] Correct watermark/late events in side-output
With this, the CEP library assumes correctness of the watermark
and considers as late, events that arrive having a timestamp
smaller than that of the last seen watermark. Late events are not
silently dropped, but the user can specify to send them to a side
output.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/kl0u/flink late-element-cep
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/flink/pull/3644.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 #3644
----
commit 827bd85916206e36ed23564e77e5ff119bfadead
Author: kl0u <[email protected]>
Date: 2017-03-23T18:01:15Z
[FLINK-6205] [FLINK-6069] [cep] Correct watermark/late events in side
output.
With this, the CEP library assumes correctness of the watermark
and considers as late, events that arrive having a timestamp
smaller than that of the last seen watermark. Late events are not
silently dropped, but the user can specify to send them to a side
output.
----
> Put late elements in side output.
> ---------------------------------
>
> Key: FLINK-6205
> URL: https://issues.apache.org/jira/browse/FLINK-6205
> Project: Flink
> Issue Type: Bug
> Components: CEP
> Affects Versions: 1.3.0
> Reporter: Kostas Kloudas
> Assignee: Kostas Kloudas
> Fix For: 1.3.0
>
>
> Currently the CEP library had a somehow fuzzy way to handle late events.
> Essentially:
> 1) it accepts all events (late and early)
> 2) it sorts them based on event time
> 3) whenever a watermark arrives, it feeds them into the NFA.
> This does not respect event time, as late events are still processed.
> In addition, given that the order in which elements are processed matters,
> this could lead to wrong results as events may be processed by the NFA
> out-of-order with respect to their timestamps.
> This issue proposes to assume correctness of the watermark and consider as
> late, events that arrive having a timestamp smaller than that of the last
> seen watermark. In addition, late events are not silently dropped, but the
> user can specify to send them to a side output, as done in the case of the
> {{WindowOperator}}.
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