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https://issues.apache.org/jira/browse/CRUNCH-485?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14268980#comment-14268980
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Tycho Lamerigts commented on CRUNCH-485:
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It looks like it could work to me. I didn't run it. And it's not that ugly
either, you can't help it that org.apache.avro.Schema is not already
Serializable. :-) I don't know this project's process - do you need anything
more from me, or do I now just wait until it makes it into 0.12 or so?
> groupByKey on Spark incorrect if key is Avro record with defined sort order
> ---------------------------------------------------------------------------
>
> Key: CRUNCH-485
> URL: https://issues.apache.org/jira/browse/CRUNCH-485
> Project: Crunch
> Issue Type: Bug
> Components: Core
> Affects Versions: 0.11.0
> Reporter: Tycho Lamerigts
> Assignee: Josh Wills
> Attachments: CRUNCH-485.patch
>
>
> GroupByKey on Spark is incorrect if the key type is an Avro record with
> defined sort order (http://avro.apache.org/docs/1.7.7/spec.html#order).
> Instead, it serializes the entire avro record to a binary blob (byte array)
> and groups identical blobs. This is wrong. By contrast, groupByKey on
> MapReduce works as expected, so it does take Avro's sort order into account.
> The culprit is probably the following code from
> org.apache.crunch.impl.spark.collect.PGroupedTableImpl#getJavaRDDLikeInternal
> {code}
> groupedRDD = parentRDD.map(new PairMapFunction(ptype.getOutputMapFn(),
> runtime.getRuntimeContext()))
> .mapToPair(new MapOutputFunction(keySerde, valueSerde))
> .groupByKey(numPartitions);
> {code}
> where MapOutputFunction simply converts the entire key object to a binary
> blob, without taking sort order into account.
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