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Posted to dev@crunch.apache.org by "Josh Wills (JIRA)" <ji...@apache.org> on 2014/07/06 04:11:33 UTC

[jira] [Created] (CRUNCH-437) Fix Crunch Spark duplicate value aggregation

Josh Wills created CRUNCH-437:
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             Summary: Fix Crunch Spark duplicate value aggregation
                 Key: CRUNCH-437
                 URL: https://issues.apache.org/jira/browse/CRUNCH-437
             Project: Crunch
          Issue Type: Bug
            Reporter: Josh Wills


The current Crunch-on-Spark mapside combiner uses a Multimap of key-value pairs to cache values for local aggregation. This is awesome, except it means that identical key-value outputs before a shuffle will only have one copy in the Multimap, which means that the aggregation counts may not be correct. We should fix it to use a proper Map<K, List<V>> to ensure that duplicate values are aggregated correctly.



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