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Posted to user@hive.apache.org by Jie Li <ji...@cs.duke.edu> on 2013/01/05 04:46:42 UTC

Map-only aggregation

Hi all,

Can Hive implement the aggregation as a Map-only job? As we know the
data may be pre-partitioned via PARTITION-BY or CLUSTERED-BY, so we
don't need the reduce phase to repartition the data.

The Bucket Join seems to take advantage of the buckets for joins, so I
wonder if there is some similar optimization for aggregations.

Thanks,
Jie