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Posted to dev@hive.apache.org by "Namit Jain (JIRA)" <ji...@apache.org> on 2009/11/27 18:49:20 UTC
[jira] Resolved: (HIVE-949) Object deepCopy in GroupBy Operator
[ https://issues.apache.org/jira/browse/HIVE-949?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Namit Jain resolved HIVE-949.
-----------------------------
Resolution: Fixed
Fix Version/s: 0.5.0
Hadoop Flags: [Reviewed]
Committed. Thanks yongqiang
> Object deepCopy in GroupBy Operator
> -----------------------------------
>
> Key: HIVE-949
> URL: https://issues.apache.org/jira/browse/HIVE-949
> Project: Hadoop Hive
> Issue Type: Improvement
> Reporter: Ning Zhang
> Assignee: He Yongqiang
> Fix For: 0.5.0
>
> Attachments: hive-949-2009-11-26.patch
>
>
> 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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