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From earellano <eric.arell...@ge.com>
Subject Re: Kafka Producer - Null Pointer Exception when processing by element
Date Mon, 17 Jul 2017 18:43:04 GMT
Tzu-Li (Gordon) Tai wrote
> Basically, when two operators are chained together, the output of the
> first operator is immediately chained to the processElement of the next
> operator; it’s therefore just a consecutive invocation of processElements
> on the chained operators. There will be no thread-to-thread handover or
> buffering.

Okay great, chaining tasks does sound like what we want then.



Tzu-Li (Gordon) Tai wrote
> In that case, I would suggest using flatMap here, followed by chained
> splits and then sinks.

We changed our code to roughly follow this suggestion, but I'm not sure
we're doing this correctly? Is there a better way you recommend chaining the
tasks? As written below, are individual Events within the List being sent to
their respective sinks right away, or does the whole list have to split
first?
<http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/file/n14312/split-stream.png>


We also had issues getting flatMap to work, and map seemed more appropriate.
Our parser.parse() function has a one-to-one mapping between an input byte[]
to a List<SuperclassEvent>, and that never changes, so a map seems to make
sense to us. Were you suggesting a flatMap instead of map at this stage of
calling our parser, or did you mean to use a flatMap() after the parser and
before the split()?



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