[
https://issues.apache.org/jira/browse/HIVE-8435?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14192973#comment-14192973
]
Pengcheng Xiong commented on HIVE-8435:
---------------------------------------
Initially I expect this patch can help me solve the external/internal name
problem for groupby index when CBO is turned on. However, it seems that it does
not work for a simple query even without index. :)
A query to show that it does not work:
select key, count(key)
from src
group by key;
set hive.cbo.enable=true;
select key, count(key)
from src
group by key;
> Add identity project remover optimization
> -----------------------------------------
>
> Key: HIVE-8435
> URL: https://issues.apache.org/jira/browse/HIVE-8435
> Project: Hive
> Issue Type: New Feature
> Components: Logical Optimizer
> Affects Versions: 0.9.0, 0.10.0, 0.11.0, 0.12.0, 0.13.0
> Reporter: Ashutosh Chauhan
> Assignee: Sergey Shelukhin
> Attachments: HIVE-8435.02.patch, HIVE-8435.03.patch,
> HIVE-8435.03.patch, HIVE-8435.04.patch, HIVE-8435.05.patch,
> HIVE-8435.05.patch, HIVE-8435.06.patch, HIVE-8435.1.patch, HIVE-8435.patch
>
>
> In some cases there is an identity project in plan which is useless. Better
> to optimize it away to avoid evaluating it without any benefit at runtime.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
