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https://issues.apache.org/jira/browse/FLINK-6969?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16080719#comment-16080719
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ASF GitHub Bot commented on FLINK-6969:
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Github user sunjincheng121 commented on the issue:
https://github.com/apache/flink/pull/4183
Yes, @fhueske you are right, we must define watermark for each table. And I
was trying to consider the semantics of Flink configs, including (FLINK-6649,
FLINK-6962, FLINK-6969 etc), I was writing google doc, and when I was done we
can discuss in doc. :)
Thanks, Jincheng
> Add support for deferred computation for group window aggregates
> ----------------------------------------------------------------
>
> Key: FLINK-6969
> URL: https://issues.apache.org/jira/browse/FLINK-6969
> Project: Flink
> Issue Type: New Feature
> Components: Table API & SQL
> Reporter: Fabian Hueske
> Assignee: sunjincheng
> Attachments: screenshot-1.png
>
>
> Deferred computation is a strategy to deal with late arriving data and avoid
> updates of previous results. Instead of computing a result as soon as it is
> possible (i.e., when a corresponding watermark was received), deferred
> computation adds a configurable amount of slack time in which late data is
> accepted before the result is compute. For example, instead of computing a
> tumbling window of 1 hour at each full hour, we can add a deferred
> computation interval of 15 minute to compute the result quarter past each
> full hour.
> This approach adds latency but can reduce the number of update esp. in use
> cases where the user cannot influence the generation of watermarks. It is
> also useful if the data is emitted to a system that cannot update result
> (files or Kafka). The deferred computation interval should be configured via
> the {{QueryConfig}}.
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