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From Chen Qin ...@uber.com>
Subject Re: [Discuss] FLIP-13 Side Outputs in Flink
Date Thu, 03 Nov 2016 15:31:30 GMT
Adding another abstract method to Collector interface is also considerably
easier from API backward compatibility point of view.

The cost could be either

1) many class with empty implementation of *<S> void collect(OutputTag<S>
tag, S value) *method

2) split streamrecord related classes that implement Collector interface
from graph generator related classes. For streamrecord ones, we might be
able to implement *collect(T out)* by calling *<S> void
collect(OutputTag<S> tag, S value). *For graph generator keep it as it is.


On Wed, Nov 2, 2016 at 8:14 PM, Chen Qin <cq@uber.com> wrote:

> Hi Fabian
>
> Thanks for your feedback. sorry for late reply.
> Some of comments inline. Will update FLIP-13 wiki reflect your comments.
>
>
> - Will multiple side outputs of the same type be supported?
>
> > It wasn't implemented in prototype. But should be easy to support, we
> have unique id in stream record.
>
> - If I got it right, the FLIP proposes to change the signatures of many
>
> user-defined functions (FlatMapFunction, WindowFunction, ...). Most of
>
> these interfaces/classes are annotated with @Public, which means we cannot
>
> change them in the Flink 1.x release line. What would be alternatives? I
>
> can think of
> a) casting the Collector into a RichCollector (as you do in
>
> your prototype) or
> > This is like a private magic API. Should be 100% compatible but not good
> implementation.
>
> b) retrieve the RichCollector from the RuntimeContext
>
> > It seems better option, yet many highly used Function like FlatMap will
> not get support. To get support, we need to create some redundant classes
> inherited from RichFunction( like implement RichFlatMap etc) [we might put
> these in different package and isolate impact of this change)
>
> that a RichFunction provides.
>
>
> I'm not so familiar with the internals of the DataStream API, so I leave
>
> comments on that to other.
>
>
> Best, Fabian
>
> On Tue, Oct 25, 2016 at 9:00 AM, Chen Qin <cq@uber.com> wrote:
>
>> Hey folks,
>>
>> Please give feedback on FLIP-13!
>> https://cwiki.apache.org/confluence/display/FLINK/FLIP-13+
>> Side+Outputs+in+Flink
>> JIRA task link to google doc https://issues.apache.org/
>> jira/browse/FLINK-4460
>>
>> Thanks,
>> Chen Qin
>>
>
>
>
> --
> -Chen Qin
>



-- 
-Chen Qin

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