ASF GitHub Bot logged work on BEAM-5063:

                Author: ASF GitHub Bot
            Created on: 10/Aug/18 13:02
            Start Date: 10/Aug/18 13:02
    Worklog Time Spent: 10m 
      Work Description: krzysztof-tr commented on issue #6178: [BEAM-5063] Fix 
Watermark does not progress for low traffic streams
URL: https://github.com/apache/beam/pull/6178#issuecomment-412075420
   @iemejia, Could you take a look at the changes and merge them if they are ok 
with you?

This is an automated message from the Apache Git Service.
To respond to the message, please log on GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:

Issue Time Tracking

    Worklog Id:     (was: 133573)
    Time Spent: 40m  (was: 0.5h)

> Watermark does not progress for low traffic streams
> ---------------------------------------------------
>                 Key: BEAM-5063
>                 URL: https://issues.apache.org/jira/browse/BEAM-5063
>             Project: Beam
>          Issue Type: Bug
>          Components: io-java-kinesis
>    Affects Versions: 2.5.0
>            Reporter: Krzysztof Trubalski
>            Assignee: Jean-Baptiste Onofré
>            Priority: Major
>          Time Spent: 40m
>  Remaining Estimate: 0h
> We have a Dataflow Job copying data from multiple Kinesis streams into Big 
> Query. Recently we have noticed that the watermark on one of the streams 
> frequently gets stuck although data from that stream is still being processed 
> (it progress only when the traffic increases or Dataflow autoscaling feature 
> kicks in).
>  Looking at the CloudWatch statistics for the affected stream, it has a 
> really low traffic rate - only ~1 event every few minutes . After 
> investigation and consulting the issue with Google's Dataflow Team, it looks 
> like with such small amount of data on the stream, the function calculating 
> the watermark in KinesisReader reports progress incorrectly.
>  From my initial investigation, I suspect that the issue might be related to 
> usage of MovingFunction in KinesisReader. In the current implementation, it 
> covers 1 minute period of samples, since obtaining the min value flushes 
> stale values, if the traffic is very low the following call to significance 
> check always returns false (as it relies on the number of samples, and most 
> of them were flushed by get() invocation).

This message was sent by Atlassian JIRA

Reply via email to