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https://issues.apache.org/jira/browse/HIVE-20270?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sahil Takiar reassigned HIVE-20270:
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> Don't serialize hashCode for groupByKey
> ---------------------------------------
>
> Key: HIVE-20270
> URL: https://issues.apache.org/jira/browse/HIVE-20270
> Project: Hive
> Issue Type: Bug
> Components: Spark
> Reporter: Sahil Takiar
> Assignee: Sahil Takiar
> Priority: Major
>
> Similar to HIVE-20032, but for {{groupByKey}}. The tricky part with
> {{groupByKey}} is we need to preserve the {{hashCode}} until the key gets
> partitioned (via the {{HashPartitioner}}) but after that we don't really need
> to preserve the {{hashCode}}. The {{groupByKey}} operator in Spark does
> require a {{hashCode}} since it puts everything in a map, but it can use a
> different hash-code than the one specified in {{HiveKey}}. The hashcode in
> {{HiveKey}} is only important for determining the partition the key should be
> assigned to.
> The drawback is that computing the hashcode for each {{HiveKey}} might
> require more CPU resources, but we should profile it just in case.
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