[jira] [Resolved] (SPARK-12125) pull out nondeterministic expressions from Join

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

     [ https://issues.apache.org/jira/browse/SPARK-12125?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Sean Owen resolved SPARK-12125.
-------------------------------
    Resolution: Won't Fix

> pull out nondeterministic expressions from Join
> -----------------------------------------------
>
>                 Key: SPARK-12125
>                 URL: https://issues.apache.org/jira/browse/SPARK-12125
>             Project: Spark
>          Issue Type: Bug
>          Components: SQL
>    Affects Versions: 1.5.2
>            Reporter: iward
>            Priority: Minor
>
> Currently,*nondeterministic expressions* are only allowed in *Project* or *Filter*,And only when we use nondeterministic expressions in *UnaryNode* can be pulled out.
> But,Sometime in many case,we will use nondeterministic expressions to process *join keys* avoiding data skew.for example:
> {noformat}
> select * 
> from tableA a 
> join 
> (select * from tableB) b 
> on upper((case when (a.brand_code is null or a.brand_code = '' ) then cast( (-rand() * 10000000 ) as string ) else a.brand_code end ))  = b.brand_code
> {noformat}
> This PR introduce a mechanism to pull out nondeterministic expressions from *Join*,so we can use nondeterministic expression in *Join* appropriately.



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