[
https://issues.apache.org/jira/browse/HIVE-13069?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15174537#comment-15174537
]
Ashutosh Chauhan commented on HIVE-13069:
-----------------------------------------
+1
> Enable cartesian product merging
> --------------------------------
>
> Key: HIVE-13069
> URL: https://issues.apache.org/jira/browse/HIVE-13069
> Project: Hive
> Issue Type: Improvement
> Components: Parser
> Reporter: Jesus Camacho Rodriguez
> Assignee: Jesus Camacho Rodriguez
> Attachments: HIVE-13069.01.patch, HIVE-13069.patch
>
>
> Currently we can merge 2-way joins into n-way joins when the joins are
> executed over the same column.
> In turn, CBO might produce plans containing cartesian products if the join
> columns are constant values; after HIVE-12543 went in, this is rather common,
> as those constant columns are correctly pruned. However, currently we do not
> merge a cartesian product with two inputs into a cartesian product with
> multiple inputs, which could result in performance loss.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
