hive-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Ashutosh Chauhan (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HIVE-4952) When hive.join.emit.interval is small, queries optimized by Correlation Optimizer may generate wrong results
Date Fri, 02 Aug 2013 04:53:49 GMT

     [ https://issues.apache.org/jira/browse/HIVE-4952?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Ashutosh Chauhan updated HIVE-4952:
-----------------------------------

       Resolution: Fixed
    Fix Version/s: 0.12.0
           Status: Resolved  (was: Patch Available)

Committed to trunk. Thanks, Yin!
                
> When hive.join.emit.interval is small, queries optimized by Correlation Optimizer may
generate wrong results
> ------------------------------------------------------------------------------------------------------------
>
>                 Key: HIVE-4952
>                 URL: https://issues.apache.org/jira/browse/HIVE-4952
>             Project: Hive
>          Issue Type: Bug
>    Affects Versions: 0.12.0
>            Reporter: Yin Huai
>            Assignee: Yin Huai
>             Fix For: 0.12.0
>
>         Attachments: HIVE-4952.D11889.1.patch, HIVE-4952.D11889.2.patch, replay.txt
>
>
> If we have a query like this ...
> {code:sql}
> SELECT xx.key, xx.cnt, yy.key
> FROM
> (SELECT x.key as key, count(1) as cnt FROM src1 x JOIN src1 y ON (x.key = y.key) group
by x.key) xx
> JOIN src yy
> ON xx.key=yy.key;
> {\code}
> After Correlation Optimizer, the operator tree in the reducer will be 
> {code}
>      JOIN2
>        |
>        |
>       MUX
>      /   \
>     /     \
>    GBY     |
>     |      |
>   JOIN1    |
>     \     /
>      \   /
>      DEMUX
> {\code}
> For JOIN2, the right table will arrive at this operator first. If hive.join.emit.interval
is small, e.g. 1, JOIN2 will output the results even it has not got any row from the left
table. The logic related hive.join.emit.interval in JoinOperator assumes that inputs will
be ordered by the tag. But, if a query has been optimized by Correlation Optimizer, this assumption
may not hold for those JoinOperators inside the reducer.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira

Mime
View raw message