[
https://issues.apache.org/jira/browse/HIVE-1239?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Namit Jain reassigned HIVE-1239:
--------------------------------
Assignee: Ning Zhang
> Make the reducer limit-aware
> ----------------------------
>
> Key: HIVE-1239
> URL: https://issues.apache.org/jira/browse/HIVE-1239
> Project: Hadoop Hive
> Issue Type: Improvement
> Affects Versions: 0.6.0
> Reporter: Ning Zhang
> Assignee: Ning Zhang
> Fix For: 0.6.0
>
>
> Currently if a join followed by a limit operator, the reducer still need to
> do a lot of work even after the limit is reached.
> A plan could look like:
> ExecReducer -> ExtractOperator -> Limit Operator -> ...
> In Hadoop 0.20, we can overwrite the reduce API to stop taking rows from the
> underlying file, but for pre-0.20, it is not overwritable. What we can do is
> to put the limit number in the ExecReducer metadata in the hive optimization
> phase.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
