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From "Keisuke Ogiwara (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-11528) incrementally read query results when there's no ORDER BY
Date Wed, 09 Dec 2015 05:22:11 GMT

    [ https://issues.apache.org/jira/browse/HIVE-11528?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15048061#comment-15048061
] 

Keisuke Ogiwara commented on HIVE-11528:
----------------------------------------

Hi All,

I have two questions  for this JIRA.

First, the work flow for query with "order by". I think we collect the results of all the
reducers into a HDFS file, and then output the file content to user console, am I right?

Second, if I am right about the first question, what happened if we run a query without "order
by"? Do we collect the results of all the reducers into a HDFS file just like what we do for
query with "order by"? Or, we do not store the results into a HDFS file. Instead, we output
the results of reduces directly to the console of the user?

Please could you give me some advice. Thank you.

> incrementally read query results when there's no ORDER BY
> ---------------------------------------------------------
>
>                 Key: HIVE-11528
>                 URL: https://issues.apache.org/jira/browse/HIVE-11528
>             Project: Hive
>          Issue Type: Improvement
>            Reporter: Sergey Shelukhin
>            Assignee: Keisuke Ogiwara
>
> May require HIVE-11527. When there's no ORDER BY and there's more than one reducer on
the last stage of the query, it should be possible to return data to the user as it is produced,
instead of waiting for all reducers to finish.



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