[jira] [Commented] (SPARK-17298) Require explicit CROSS join for cartesian products by default

["Srinath (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/SPARK-17298?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15447642#comment-15447642 ] 

Srinath commented on SPARK-17298:
---------------------------------

I've updated the description. Hopefully it is clearer.
Note that before this change, even with spark.sql.crossJoin.enabled = false,
case 1.a may sometimes NOT throw an error (i.e. execute successfully) depending on the physical plan chosen.
With the proposed  change, it would always throw an error

> Require explicit CROSS join for cartesian products by default
> -------------------------------------------------------------
>
>                 Key: SPARK-17298
>                 URL: https://issues.apache.org/jira/browse/SPARK-17298
>             Project: Spark
>          Issue Type: Story
>          Components: SQL
>            Reporter: Srinath
>            Priority: Minor
>
> Require the use of CROSS join syntax in SQL (and a new crossJoin DataFrame API) to specify explicit cartesian products between relations under the default configuration (spark.sql.crossJoin.enabled = false).
> By cartesian product we mean a join between relations R and S where there is no join condition involving columns from both R and S.
> If a cartesian product is detected in the absence of an explicit CROSS join, an error must be thrown. 
> Turning on the spark.sql.crossJoin.enabled configuration flag will disable this check and allow cartesian products without an explicit cross join.



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

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