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From "Jesus Camacho Rodriguez (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HIVE-13069) Enable cartesian product merging
Date Tue, 01 Mar 2016 19:41:18 GMT

     [ https://issues.apache.org/jira/browse/HIVE-13069?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Jesus Camacho Rodriguez updated HIVE-13069:
-------------------------------------------
    Attachment: HIVE-13069.01.patch

> 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.



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