spark-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Dongjoon Hyun (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (SPARK-21858) Make Spark grouping_id() compatible with Hive grouping__id
Date Thu, 14 Sep 2017 15:38:00 GMT

    [ https://issues.apache.org/jira/browse/SPARK-21858?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16166467#comment-16166467
] 

Dongjoon Hyun commented on SPARK-21858:
---------------------------------------

Thank you for conclusion, [~cloud_fan]!

> Make Spark grouping_id() compatible with Hive grouping__id
> ----------------------------------------------------------
>
>                 Key: SPARK-21858
>                 URL: https://issues.apache.org/jira/browse/SPARK-21858
>             Project: Spark
>          Issue Type: Bug
>          Components: SQL
>    Affects Versions: 2.2.0
>            Reporter: Yann Byron
>
> If you want to migrate some ETLs using `grouping__id` in Hive to Spark and use Spark
`grouping_id()` instead of Hive `grouping__id`, you will find difference between their evaluations.
> Here is an example.
> {code:java}
> select A, B, grouping__id/grouping_id() from t group by A, B grouping sets((), (A), (B),
(A,B))
> {code}
> Running it on Hive and Spark separately, you'll find this: (the selected attribute in
selected grouping set is represented by (/) and  otherwise by (x))
> ||A B||Binary Expression in Spark||Spark||Hive||Binary Expression in Hive||B A||
> |(x) (x)|11|3|0|00|(x) (x)|
> |(x) (/)|10|2|2|10|(/) (x)|
> |(/) (x)|01|1|1|01|(x) (/)|
> |(/) (/)|00|0|3|11|(/) (/)|
> As shown above´╝îIn Hive, (/) set to 0, (x) set to 1, and in Spark it's opposite.
> Moreover, attributes in `group by` will reverse firstly in Hive. In Spark it'll be evaluated
directly.
> In my opinion, I suggest that modifying the behavior of `grouping_id()` make it compatible
with Hive `grouping__id`.



--
This message was sent by Atlassian JIRA
(v6.4.14#64029)

---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscribe@spark.apache.org
For additional commands, e-mail: issues-help@spark.apache.org


Mime
View raw message