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From Chesnay Schepler <ches...@apache.org>
Subject Re: Key by Task number
Date Tue, 18 Apr 2017 14:16:37 GMT
If the number of combinations between partition and schemaID is limited 
then the subtask index could actually improve the distribution of values.

In any case, the easiest way to do this is to add a RichMapFunction 
after the flatMap, or modify the flatMap, to also include the subtask index.
Typically this would be done by creating a Tuple2 containing the index 
and value.

On 18.04.2017 15:43, Kamil Dziublinski wrote:
> I am not sure if you really need a keyby, your load will be 
> distributed among your map function without it.  But could you explain 
> a bit what is your sink doing?
>
>
> As for setting parallelism on the consumer remember that you wont have 
> higher parallelism than number of partitions in your topic.
> If you have 240 partitions that's fine, but if you have less than 
> other subtasks will be idle. Only one task can read from one partition 
> in parallel.
>
> On Tue, Apr 18, 2017 at 3:38 PM Telco Phone <telco5@yahoo.com 
> <mailto:telco5@yahoo.com>> wrote:
>
>
>     I am trying to use the task number as a keyby value to help fan
>     out the work load reading from kafka.
>
>
>     Given:
>
>            DataStream<SchemaRecord> stream =
>                     env.addSource(new
>     FlinkKafkaConsumer010<SchemaRecord>("topicA", schema, properties)
>                   ).setParallelism(240).flatMap(new
>     SchemaRecordSplit()).setParallelism(240).
>                           name("TopicA splitter").keyBy("partition",
>     "keyByHelper", "schemaId");
>
>           stream.addSink(new CustomMaprFsSink()).name("TopicA
>     Sink").setParallelism(240);
>
>
>     In the DeserialClass I am trying to get to the
>
>     getRuntimeContext().getIndexOfThisSubtask();
>
>     Which is only avaliable in the RichSinkFunction
>
>
>
>     The above is partition (by hour) , schemaID (avro schemaId) and I
>     would like to add the task number so that all 240 readers /
>     writers have something to do.
>
>     Any ideas ?
>
>
>


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