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https://issues.apache.org/jira/browse/HIVE-2340?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13568361#comment-13568361
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Navis commented on HIVE-2340:
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@Gunther Hagleitner,
This optimization copies configuration of childRS to parentRS, which can lead
to performance problems if childRS is run on single or small number of RSs
(bucketing, etc), especially when parentRS is for JOIN or GBY. Thresholding it
by "min.reducer" conf seemed not good enough. Do you have some better idea?
> optimize orderby followed by a groupby
> --------------------------------------
>
> Key: HIVE-2340
> URL: https://issues.apache.org/jira/browse/HIVE-2340
> Project: Hive
> Issue Type: Sub-task
> Components: Query Processor
> Reporter: Navis
> Assignee: Navis
> Priority: Minor
> Labels: perfomance
> Attachments: ASF.LICENSE.NOT.GRANTED--HIVE-2340.D1209.1.patch,
> ASF.LICENSE.NOT.GRANTED--HIVE-2340.D1209.2.patch,
> ASF.LICENSE.NOT.GRANTED--HIVE-2340.D1209.3.patch,
> ASF.LICENSE.NOT.GRANTED--HIVE-2340.D1209.4.patch,
> ASF.LICENSE.NOT.GRANTED--HIVE-2340.D1209.5.patch, HIVE-2340.1.patch.txt,
> HIVE-2340.D1209.6.patch, HIVE-2340.D1209.7.patch, HIVE-2340.D1209.8.patch,
> HIVE-2340.D1209.9.patch, testclidriver.txt
>
>
> Before implementing optimizer for JOIN-GBY, try to implement RS-GBY
> optimizer(cluster-by following group-by).
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