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From "Josh Wills (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (CRUNCH-437) Fix Crunch Spark duplicate value aggregation
Date Sun, 06 Jul 2014 02:17:34 GMT

     [ https://issues.apache.org/jira/browse/CRUNCH-437?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Josh Wills updated CRUNCH-437:
------------------------------

    Attachment: CRUNCH-437.patch

Patch for the same.

> 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
>         Attachments: CRUNCH-437.patch
>
>
> 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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