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https://issues.apache.org/jira/browse/FLINK-20190?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17235221#comment-17235221
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Robert Metzger commented on FLINK-20190:
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Thanks a lot for opening a ticket. Please note that according to our code
contribution guidelines
(https://flink.apache.org/contributing/contribute-code.html), we first need to
decide if a new feature is a good fit for Flink. I'll leave it to Aljoscha and
other committers working on the APIs to decide that.
> A New Window Trigger that can trigger window operation both by event time
> interval、event count for DataStream API
> -----------------------------------------------------------------------------------------------------------------
>
> Key: FLINK-20190
> URL: https://issues.apache.org/jira/browse/FLINK-20190
> Project: Flink
> Issue Type: New Feature
> Components: API / DataStream
> Reporter: GaryGao
> Priority: Major
> Fix For: 1.12.0
>
>
> In production environment, when we are do some window operation, such as
> window aggregation, using data stream api, developers are always asked to not
> only trigger the window operation when the watermark pass the max timestamp
> of window, but also trigger it both by fixed event time interval and fixed
> count of event.The reason why we want to do this is we are looking forward to
> get the frequently updated window operation result, other than waiting for a
> long time until the watermark pass the max timestamp of window.This is very
> useful in reporting and other BI applications.
> For now the default triggers provided by flink can not close this
> requirement, so I developed a New Trigger, so called
> CountAndContinuousEventTimeTrigger, combine ContinuousEventTimeTrigger with
> CountTrigger to do the above thing.
>
> To use CountAndContinuousEventTimeTrigger, you should specify two parameters
> as revealed in it constructor:
> {code:java}
> private CountAndContinuousEventTimeTrigger(Time interval, long
> maxCount);{code}
> * Time interval, it means this trigger will continuously fires based on a
> given time interval, the same as ContinuousEventTimeTrigger.
> * long maxCount, it means this trigger will fires once the count of elements
> in a pane reaches the given count, the same as CountTrigger.
>
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