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https://issues.apache.org/jira/browse/HIVE-13982?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jesus Camacho Rodriguez updated HIVE-13982:
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Attachment: HIVE-13982.3.patch
> Extension to limit push down through order by & group by
> --------------------------------------------------------
>
> Key: HIVE-13982
> URL: https://issues.apache.org/jira/browse/HIVE-13982
> Project: Hive
> Issue Type: Improvement
> Components: Physical Optimizer
> Affects Versions: 2.2.0
> Reporter: Jesus Camacho Rodriguez
> Assignee: Jesus Camacho Rodriguez
> Attachments: HIVE-13982.2.patch, HIVE-13982.3.patch, HIVE-13982.patch
>
>
> Pointed out by [~gopalv].
> Queries which follow the format are not optimal with map-side aggregation,
> because the Map 1 does not have TopN in the reduce sink.
> These queries shuffle 100% of the aggregate in cases where the reduce de-dup
> does not kick in.
> {code}
> select state, city, sum(sales) from table
> group by state, city
> order by state, city
> limit 10;
> {code}
> {code}
> select state, city, sum(sales) from table
> group by city, state
> order by state, city
> limit 10;
> {code}
> {code}
> select state, city, sum(sales) from table
> group by city, state
> order by state desc, city
> limit 10;
> {code}
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