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Posted to user@flink.apache.org by "Sofer, Tovi " <to...@citi.com> on 2018/07/16 12:17:08 UTC

event time and late events - documentation 

Hi group,
Can someone please elaborate on the comment at the end of section "Debugging Windows & Event Time"?
Didn't understand it meaning.
https://ci.apache.org/projects/flink/flink-docs-master/monitoring/debugging_event_time.html
"Handling Event Time Stragglers
Approach 1: Watermark stays late (indicated completeness), windows fire early
Approach 2: Watermark heuristic with maximum lateness, windows accept late data"

Thanks,
Tovi

Re: event time and late events - documentation

Posted by vino yang <ya...@gmail.com>.
Hi Tovi,

1. approach 1 : change the watermark let it means the later time, window
trigger early.
2. approach 2 : do not change the watermark, but specify the allow lateness
for the window[1][2], this way can make window accept late element and
re-fire the window after watermark.

[1]:
https://ci.apache.org/projects/flink/flink-docs-master/dev/event_time.html#late-elements
[2]:
https://ci.apache.org/projects/flink/flink-docs-master/dev/stream/operators/windows.html#allowed-lateness

Thanks, vino.

2018-07-16 23:28 GMT+08:00 Elias Levy <fe...@gmail.com>:

> Tovi,
>
> The document here
> <https://docs.google.com/document/d/1b5d-hTdJQsPH3YD0zTB4ZqodinZVHFomKvt41FfUPMc/edit?usp=sharing>
> should answer your question.  If it doesn't, please let me know.
>
> On Mon, Jul 16, 2018 at 5:17 AM Sofer, Tovi <to...@citi.com> wrote:
>
>> Hi group,
>>
>> Can someone please elaborate on the comment at the end of section
>> “Debugging Windows & Event Time”?
>>
>> Didn’t understand it meaning.
>>
>> https://ci.apache.org/projects/flink/flink-docs-
>> master/monitoring/debugging_event_time.html
>>
>> *“Handling Event Time Stragglers*
>>
>> *Approach 1: Watermark stays late (indicated completeness), windows fire
>> early*
>>
>> *Approach 2: Watermark heuristic with maximum lateness, windows accept
>> late data”*
>>
>>
>>
>> Thanks,
>>
>> Tovi
>>
>

Re: event time and late events - documentation

Posted by Elias Levy <fe...@gmail.com>.
Tovi,

The document here
<https://docs.google.com/document/d/1b5d-hTdJQsPH3YD0zTB4ZqodinZVHFomKvt41FfUPMc/edit?usp=sharing>
should answer your question.  If it doesn't, please let me know.

On Mon, Jul 16, 2018 at 5:17 AM Sofer, Tovi <to...@citi.com> wrote:

> Hi group,
>
> Can someone please elaborate on the comment at the end of section
> “Debugging Windows & Event Time”?
>
> Didn’t understand it meaning.
>
>
> https://ci.apache.org/projects/flink/flink-docs-master/monitoring/debugging_event_time.html
>
> *“Handling Event Time Stragglers*
>
> *Approach 1: Watermark stays late (indicated completeness), windows fire
> early*
>
> *Approach 2: Watermark heuristic with maximum lateness, windows accept
> late data”*
>
>
>
> Thanks,
>
> Tovi
>