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From "Namit Jain (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-2068) Speed up query "select xx,xx from xxx LIMIT xxx" if no filtering or aggregation
Date Fri, 15 Apr 2011 18:24:06 GMT

    [ https://issues.apache.org/jira/browse/HIVE-2068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13020386#comment-13020386
] 

Namit Jain commented on HIVE-2068:
----------------------------------

FetchTask: return false if number of rows found.
Else, it looks good

> Speed up query "select xx,xx from xxx LIMIT xxx" if no filtering or aggregation
> -------------------------------------------------------------------------------
>
>                 Key: HIVE-2068
>                 URL: https://issues.apache.org/jira/browse/HIVE-2068
>             Project: Hive
>          Issue Type: Improvement
>            Reporter: Siying Dong
>            Assignee: Siying Dong
>         Attachments: HIVE-2068.1.patch, HIVE-2068.2.patch, HIVE-2068.3.patch, HIVE-2068.4.patch,
HIVE-2068.5.patch
>
>
> Currently, "select xx,xx from xxx where ...(only partition conditions) LIMIT xxx" will
start a MapReduce job with input to be the whole table or partition. The latency can be huge
if the table or partition is big. We could reduce number of input files to speed up the queries.

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