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https://issues.apache.org/jira/browse/HIVE-2925?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14053271#comment-14053271
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Navis commented on HIVE-2925:
-----------------------------

bq. What does RS mean?
Yes, it's ReduceSinkOperator, which needs a MR task to be evaluated, negating 
fetch task conversion.

bq. "LIMIT only" and "LIMIT only (TABLESAMPLE, virtual columns)" mean?
In 'minimal', it didn't allowed any virtual columns and sampling directives. 
But with 'more', the optimizer can convert those, too.

bq. Does FILTER just mean the WHERE and HAVING clauses?
Yes, and yes. It's any form of predicates in the query. And uppercase would be 
better.

> Support non-MR fetching for simple queries with select/limit/filter 
> operations only
> -----------------------------------------------------------------------------------
>
>                 Key: HIVE-2925
>                 URL: https://issues.apache.org/jira/browse/HIVE-2925
>             Project: Hive
>          Issue Type: Improvement
>    Affects Versions: 0.10.0
>            Reporter: Navis
>            Assignee: Navis
>            Priority: Trivial
>             Fix For: 0.10.0
>
>         Attachments: ASF.LICENSE.NOT.GRANTED--HIVE-2925.D2607.1.patch, 
> ASF.LICENSE.NOT.GRANTED--HIVE-2925.D2607.2.patch, 
> ASF.LICENSE.NOT.GRANTED--HIVE-2925.D2607.3.patch, 
> ASF.LICENSE.NOT.GRANTED--HIVE-2925.D2607.4.patch, HIVE-2925.1.patch.txt, 
> HIVE-2925.2.patch.txt, HIVE-2925.3.patch.txt
>
>
> It's trivial but frequently asked by end-users. Currently, select queries 
> with simple conditions or limit should run MR job which takes some time 
> especially for big tables, making the people irritated.
> For that kind of simple queries, using fetch task would make them happy.



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