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Posted to issues@spark.apache.org by "Apache Spark (Jira)" <ji...@apache.org> on 2021/03/31 12:32:00 UTC

[jira] [Commented] (SPARK-34922) Use better CBO cost function

    [ https://issues.apache.org/jira/browse/SPARK-34922?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17312316#comment-17312316 ] 

Apache Spark commented on SPARK-34922:
--------------------------------------

User 'tanelk' has created a pull request for this issue:
https://github.com/apache/spark/pull/32014

> Use better CBO cost function
> ----------------------------
>
>                 Key: SPARK-34922
>                 URL: https://issues.apache.org/jira/browse/SPARK-34922
>             Project: Spark
>          Issue Type: Improvement
>          Components: SQL
>    Affects Versions: 3.2.0
>            Reporter: Tanel Kiis
>            Priority: Major
>
> In SPARK-33935 we changed the CBO cost function such that it would be symetric - A.betterThan(B) implies that !B.betterThan(A). Before both could have been true.
> That change introduced a performance regression in some queries. 



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