You are viewing a plain text version of this content. The canonical link for it is here.

Posted to dev@hive.apache.org by "Xinyu Wang (Jira)" <ji...@apache.org> on 2020/09/12 04:11:00 UTC

[jira] [Created] (HIVE-24153) distinct is not quite effective in table expression

Xinyu Wang created HIVE-24153:
---------------------------------

             Summary: distinct is not quite effective in table expression
                 Key: HIVE-24153
                 URL: https://issues.apache.org/jira/browse/HIVE-24153
             Project: Hive
          Issue Type: Bug
          Components: Query Planning
    Affects Versions: 3.1.1
            Reporter: Xinyu Wang


Below is an example:

_t(id int, name string, comment string)._

_with cte as (_

    _select distinct id, name, comment_

    _from t_

_)_

 

_select count(*) from cte_

The result of the above query is larger than select count(distinct id, name, comment). In the result of EXPLAIN, PARTITION_ONLY_SHUFFLE is used. But for  select count(distinct id, name, comment), SHUFFLE is used instead.

 

Thanks.



--
This message was sent by Atlassian Jira
(v8.3.4#803005)