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From "Navis (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HIVE-2253) Merge failing of join tree in exceptional case
Date Mon, 04 Jul 2011 07:47:22 GMT

     [ https://issues.apache.org/jira/browse/HIVE-2253?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Navis updated HIVE-2253:
------------------------

    Attachment: HIVE-2253.patch

> Merge failing of join tree in exceptional case
> ----------------------------------------------
>
>                 Key: HIVE-2253
>                 URL: https://issues.apache.org/jira/browse/HIVE-2253
>             Project: Hive
>          Issue Type: Bug
>          Components: Query Processor
>    Affects Versions: 0.7.0
>         Environment: hadoop 0.20.2, hive 0.7.0
>            Reporter: Navis
>            Priority: Minor
>         Attachments: HIVE-2253.patch
>
>
> In some very exceptional cases, SemanticAnayzer fails to merge join tree. Example is
below.
> create table a (val1 int, val2 int)
> create table b (val1 int, val2 int)
> create table c (val1 int, val2 int)
> create table d (val1 int, val2 int)
> create table e (val1 int, val2 int)
> 1. all same(single) join key --> one MR, good
> select * from a join b on a.val1=b.val1 join c on a.val1=c.val1 join d on a.val1=d.val1
join e on a.val1=e.val1
> 2. two join keys --> expected to have two MR, but resulted to three MR
> select * from a join b on a.val1=b.val1 join c on a.val1=c.val1 join d on a.val1=d.val1
join e on a.val2=e.val2
> 3. by changing the join order, we could attain two MR as first-expectation.
> select * from a join e on a.val2=e.val2 join c on a.val1=c.val1 join d on a.val1=d.val1
join b on a.val1=b.val1

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