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Posted to issues@hive.apache.org by "Jesus Camacho Rodriguez (JIRA)" <ji...@apache.org> on 2016/06/13 14:24:21 UTC

[jira] [Updated] (HIVE-13982) Extensions to RS dedup: execute with different column order and sorting direction if possible

     [ https://issues.apache.org/jira/browse/HIVE-13982?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jesus Camacho Rodriguez updated HIVE-13982:
-------------------------------------------
    Summary: Extensions to RS dedup: execute with different column order and sorting direction if possible  (was: Extension to limit push down through order by & group by)

> Extensions to RS dedup: execute with different column order and sorting direction if possible
> ---------------------------------------------------------------------------------------------
>
>                 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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