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From "Siying Dong (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HIVE-2068) Speed up query "select xx,xx from xxx LIMIT xxx" if no filtering or aggregation
Date Thu, 31 Mar 2011 08:09:05 GMT

     [ https://issues.apache.org/jira/browse/HIVE-2068?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Siying Dong updated HIVE-2068:
------------------------------

    Attachment: HIVE-2068.3.patch

previous patch missed a file.

> 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
>
>
> 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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