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From "He Yongqiang (JIRA)" <>
Subject [jira] Commented: (HIVE-949) Object deepCopy in GroupBy Operator
Date Tue, 24 Nov 2009 02:38:43 GMT


He Yongqiang commented on HIVE-949:

no problem.

> Object deepCopy in GroupBy Operator
> -----------------------------------
>                 Key: HIVE-949
>                 URL:
>             Project: Hadoop Hive
>          Issue Type: Improvement
>            Reporter: Ning Zhang
>            Assignee: He Yongqiang
> In GroupByOperator, objects are first deep copied and then check whether or not the object
is in the hash table (in hash-mode aggregation). In fact, object deep copy could be very expensive
(around 5% CPU time). A simple change could be generate the object without deep copy through
ObjectInspector and check its existence in the hash table. If not exists, we call deep copy.

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