[
https://issues.apache.org/jira/browse/HIVE-69?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12652181#action_12652181
]
Namit Jain commented on HIVE-69:
--------------------------------
The following query will not work:
select count(1) FROM ( select a.x as x from x UNION ALL select b.x as x from
b ) out;
Union followed by reduce sink will not work - since we have already made the
child of reduce sink null.
It can be easily fixed in the new framework since tree walking/splitting etc.
are independent
> genMapRedTasks does not use the tree walker and uses implicit state which
> makes it difficult to enhance
> -------------------------------------------------------------------------------------------------------
>
> Key: HIVE-69
> URL: https://issues.apache.org/jira/browse/HIVE-69
> Project: Hadoop Hive
> Issue Type: Bug
> Components: Query Processor
> Reporter: Namit Jain
> Assignee: Namit Jain
>
> In SemanticAnalyzer, genmapredtasks() does not use a tree walker. For
> map-side joins, the taskplan needs to be enhanced to be possibly
> broken at MapSink also. Basically, the code is very difficult to enhance
> since there are implicit assumptions that reduce sink is the only
> operator where the plan breaks.
> This should be enhanced so that the user can implement their own task
> generation logic which is independent of the tree walking.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
