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https://issues.apache.org/jira/browse/SPARK-26155?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16713847#comment-16713847
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Ke Jia commented on SPARK-26155:
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Upload the result of all queries in tpcds in 1TB data scale.

> Spark SQL  performance degradation after apply SPARK-21052 with Q19 of TPC-DS 
> in 3TB scale
> ------------------------------------------------------------------------------------------
>
>                 Key: SPARK-26155
>                 URL: https://issues.apache.org/jira/browse/SPARK-26155
>             Project: Spark
>          Issue Type: Improvement
>          Components: SQL
>    Affects Versions: 2.3.0, 2.3.1, 2.3.2, 2.4.0
>            Reporter: Ke Jia
>            Priority: Major
>         Attachments: Q19 analysis in Spark2.3 with L486&487.pdf, Q19 analysis 
> in Spark2.3 without L486&487.pdf, q19.sql, tpcds.result.xlsx
>
>
> In our test environment, we found a serious performance degradation issue in 
> Spark2.3 when running TPC-DS on SKX 8180. Several queries have serious 
> performance degradation. For example, TPC-DS Q19 needs 126 seconds with Spark 
> 2.3 while it needs only 29 seconds with Spark2.1 on 3TB data. We investigated 
> this problem and figured out the root cause is in community patch SPARK-21052 
> which add metrics to hash join process. And the impact code is 
> [L486|https://github.com/apache/spark/blob/1d3dd58d21400b5652b75af7e7e53aad85a31528/sql/core/src/main/scala/org/apache/spark/sql/execution/joins/HashedRelation.scala#L486]
>  and 
> [L487|https://github.com/apache/spark/blob/1d3dd58d21400b5652b75af7e7e53aad85a31528/sql/core/src/main/scala/org/apache/spark/sql/execution/joins/HashedRelation.scala#L487]
>   . Q19 costs about 30 seconds without these two lines code and 126 seconds 
> with these code.



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