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From "Xiao Li (JIRA)" <j...@apache.org>
Subject [jira] [Resolved] (SPARK-22181) ReplaceExceptWithFilter if one or both of the datasets are fully derived out of Filters from a same parent
Date Sat, 28 Oct 2017 02:00:00 GMT

     [ https://issues.apache.org/jira/browse/SPARK-22181?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Xiao Li resolved SPARK-22181.
-----------------------------
       Resolution: Fixed
         Assignee: Sathiya Kumar
    Fix Version/s: 2.3.0

> ReplaceExceptWithFilter if one or both of the datasets are fully derived out of Filters
from a same parent
> ----------------------------------------------------------------------------------------------------------
>
>                 Key: SPARK-22181
>                 URL: https://issues.apache.org/jira/browse/SPARK-22181
>             Project: Spark
>          Issue Type: New Feature
>          Components: Optimizer, SQL
>    Affects Versions: 2.1.1, 2.2.0
>            Reporter: Sathiya Kumar
>            Assignee: Sathiya Kumar
>            Priority: Minor
>             Fix For: 2.3.0
>
>
> While applying Except operator between two datasets, if one or both of the datasets are
purely transformed using filter operations, then instead of rewriting the Except operator
using expensive join operation, we can rewrite it using filter operation by flipping the filter
condition of the right node.
> Example:
> {code:sql}
>    SELECT a1, a2 FROM Tab1 WHERE a2 = 12 EXCEPT SELECT a1, a2 FROM Tab1 WHERE a1 = 5
>    ==>  SELECT DISTINCT a1, a2 FROM Tab1 WHERE a2 = 12 AND (a1 is null OR a1 <>
5)
> {code}
> For more details please refer: [this post|https://github.com/sathiyapk/Blog-Posts/blob/master/SparkOptimizer.md]



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