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https://issues.apache.org/jira/browse/HIVE-4042?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13596241#comment-13596241
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Namit Jain commented on HIVE-4042:
----------------------------------
[~ashutoshc], I am assuming you are talking about the following query:
{noformat}
select /*+MAPJOIN(smallTableTwo)*/ idOne, idTwo, value FROM
( select /*+MAPJOIN(smallTableOne)*/ idOne, idTwo, value FROM
bigTable
JOIN
smallTableOne on (bigTable.idOne = smallTableOne.idOne)
) firstjoin
JOIN
smallTableTwo on (firstjoin.idTwo = smallTableTwo.idTwo)
{noformat}
without the mapjoin hints. This query will remain the same.
The query:
{code}
select /*+ MAPJOIN(t2) */ * from t1 join t2 on t1.t11 = t2.t21 group by
t1.t12;
{code}
will have an extra MR job (I need to verify that), which should go away by
setting hive.auto.convert.join.noconditionaltask to true.
Let me test that.
> ignore mapjoin hint
> -------------------
>
> Key: HIVE-4042
> URL: https://issues.apache.org/jira/browse/HIVE-4042
> Project: Hive
> Issue Type: Improvement
> Components: Query Processor
> Reporter: Namit Jain
> Assignee: Namit Jain
> Attachments: hive.4042.1.patch, hive.4042.2.patch, hive.4042.3.patch,
> hive.4042.4.patch, hive.4042.5.patch, hive.4042.6.patch, hive.4042.7.patch,
> hive.4042.8.patch
>
>
> After HIVE-3784, in a production environment, it can become difficult to
> deploy since a lot of production queries can break.
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