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From "Siying Dong (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HIVE-1738) Optimize Key Comparison in GroupByOperator
Date Thu, 21 Oct 2010 10:55:17 GMT

    [ https://issues.apache.org/jira/browse/HIVE-1738?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12923397#action_12923397
] 

Siying Dong commented on HIVE-1738:
-----------------------------------

One note: for the query above, input format is SequenceFile, which is not friendly to this
kind of query. I convert the input to RCFile and do the same comparison against it, I can
see Map's CPU_MILLISECONDS are improved from about 1,050,000 to about 965,000. 

> Optimize Key Comparison in GroupByOperator
> ------------------------------------------
>
>                 Key: HIVE-1738
>                 URL: https://issues.apache.org/jira/browse/HIVE-1738
>             Project: Hive
>          Issue Type: Improvement
>            Reporter: Siying Dong
>            Assignee: Siying Dong
>         Attachments: HIVE.1738.1.patch
>
>
> GroupByOperator uses ObjectInspectorUtils.compare() to compare keys, which is written
for generalized object comparisons, which is not optimized for group-by operator. By optimizing
this logic, we expect to see obvious improvements in GroupByOperator.

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