[
https://issues.apache.org/jira/browse/HIVE-17037?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Jesus Camacho Rodriguez updated HIVE-17037:
-------------------------------------------
Summary: Use 1-to-1 Tez edge to avoid unnecessary input data shuffle (was:
Extend join algorithm selection to avoid unnecessary input data shuffle)
> Use 1-to-1 Tez edge to avoid unnecessary input data shuffle
> -----------------------------------------------------------
>
> Key: HIVE-17037
> URL: https://issues.apache.org/jira/browse/HIVE-17037
> Project: Hive
> Issue Type: Improvement
> Components: Physical Optimizer
> Affects Versions: 3.0.0
> Reporter: Jesus Camacho Rodriguez
> Assignee: Jesus Camacho Rodriguez
> Attachments: HIVE-17037.01.patch, HIVE-17037.02.patch,
> HIVE-17037.03.patch, HIVE-17037.patch
>
>
> As an example, consider the following query:
> {code:sql}
> SELECT *
> FROM (
> SELECT a.value
> FROM src1 a
> JOIN src1 b
> ON (a.value = b.value)
> GROUP BY a.value
> ) a
> JOIN src
> ON (a.value = src.value);
> {code}
> Currently, the plan generated for Tez will contain an unnecessary shuffle
> operation between the subquery and the join, since the records produced by
> the subquery are already sorted by the value.
> This issue is to extend join algorithm selection to be able to shuffle only
> some of the inputs for a given join and avoid unnecessary shuffle operations.
--
This message was sent by Atlassian JIRA
(v6.4.14#64029)
