[jira] [Updated] (HIVE-12640) Allow StatsOptimizer to optimize the query for Constant GroupBy keys

["Hari Sankar Sivarama Subramaniyan (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-12640?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Hari Sankar Sivarama Subramaniyan updated HIVE-12640:
-----------------------------------------------------
    Attachment: HIVE-12640.3.patch

> Allow StatsOptimizer to optimize the query for Constant GroupBy keys 
> ---------------------------------------------------------------------
>
>                 Key: HIVE-12640
>                 URL: https://issues.apache.org/jira/browse/HIVE-12640
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Hari Sankar Sivarama Subramaniyan
>            Assignee: Hari Sankar Sivarama Subramaniyan
>         Attachments: HIVE-12640.1.patch, HIVE-12640.2.patch, HIVE-12640.3.patch
>
>
> {code}
> hive> select count('1') from src group by '1';
> {code}
> In the above query, while performing StatsOptimizer optimization we can safely ignore the group by on the constant key '1' since the above query will return the same result as "select count('1') from src".
> Exception:
> If src is empty, according to the SQL standard,
> {code}
>  select count('1') from src group by '1'
> {code}
> and
> {code}
>  select count('1') from src
> {code}
> should produce 1 and 0 rows respectively.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)