flink-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (FLINK-6969) Add support for deferred computation for group window aggregates
Date Wed, 28 Jun 2017 14:55:00 GMT

    [ https://issues.apache.org/jira/browse/FLINK-6969?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16066624#comment-16066624
] 

ASF GitHub Bot commented on FLINK-6969:
---------------------------------------

Github user fhueske commented on the issue:

    https://github.com/apache/flink/pull/4183
  
    Sorry @wuchong, I started my comment in the morning and got stuck in meetings. That's
why I didn't see your comment... It's great that we came to the same conclusion! :-)
    
    Instead of holding watermarks back at the sources, I would adjust them by subtracting
the offset. 
    What's your take on the `deferredComputationTime` vs `firstResultTimeOffset`?
    
    Thanks, Fabian


> 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
>
> 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}}.



--
This message was sent by Atlassian JIRA
(v6.4.14#64029)

Mime
View raw message