git.net

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[jira] [Created] (HIVE-20108) Investigate alternatives to groupByKey


Sahil Takiar created HIVE-20108:
-----------------------------------

             Summary: Investigate alternatives to groupByKey
                 Key: HIVE-20108
                 URL: https://issues.apache.org/jira/browse/HIVE-20108
             Project: Hive
          Issue Type: Improvement
          Components: Spark
            Reporter: Sahil Takiar
            Assignee: Sahil Takiar


We use {{groupByKey}} for aggregations (or if {{hive.spark.use.groupby.shuffle}} is false we use {{repartitionAndSortWithinPartitions}}).

{{groupByKey}} has its drawbacks because it can't spill records within a single key group. It also seems to be doing some unnecessary work in Spark's {{Aggregator}} (not positive about this part).

{{repartitionAndSortWithinPartitions}} is better, but the sorting within partitions isn't necessary for aggregations.





--
This message was sent by Atlassian JIRA
(v7.6.3#76005)