[jira] [Commented] (FLINK-2246) Add chained combine driver strategy for ReduceFunction

["Fabian Hueske (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-2246?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14593351#comment-14593351 ] 

Fabian Hueske commented on FLINK-2246:
--------------------------------------

This is an expected behavior. There is no chained driver strategy for {{ReduceFunction}} combiners (see {{SORTED_PARTIAL_REDUCE}} strategy in {{DriverStrategy.java}}). 
{{sum}} is implemented as a combinable {{GroupReduceFunction}} for which a chained driver strategy exists.

It would be good to have a chained driver strategy for {{ReduceFunction}} combiners as well.
I am changing this issue accordingly.

> Add chained combine driver strategy for ReduceFunction
> ------------------------------------------------------
>
>                 Key: FLINK-2246
>                 URL: https://issues.apache.org/jira/browse/FLINK-2246
>             Project: Flink
>          Issue Type: Improvement
>          Components: Local Runtime
>    Affects Versions: 0.9, master
>            Reporter: Ufuk Celebi
>            Priority: Minor
>
> Running the WordCount example with a text file input/output results and a manual reduce function (instead of the sum(1)) results in a combiner, which is not chained.
> Replace sum(1) with the following to reproduce and use a text file as input:
> {code}
> fileOutput = true;
> textPath = "...";
> outputPath = "...";
> {code}
> {code}
> .reduce(new ReduceFunction<Tuple2<String, Integer>>() {
>     @Override
>     public Tuple2<String, Integer> reduce(Tuple2<String, Integer> value1, Tuple2<String, Integer> value2) throws Exception {
>         return new Tuple2<String, Integer>(value1.f0, value1.f1 + value2.f1);
>     }    
> });
> {code}



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