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From Telco Phone <tel...@yahoo.com>
Subject Re: Key by Task number
Date Tue, 18 Apr 2017 23:19:06 GMT
Do you have a small example or a link to a doc that has one ?



      From: Chesnay Schepler <chesnay@apache.org>
 To: user@flink.apache.org 
 Sent: Tuesday, April 18, 2017 8:16 AM
 Subject: Re: Key by Task number
   
 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> 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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