[
https://issues.apache.org/jira/browse/SPARK-23310?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16352754#comment-16352754
]
Kazuaki Ishizaki commented on SPARK-23310:
------------------------------------------
[~juliuszsompolski] We would appreciate it if you would post internal detail
for future analysis and fixes.
> Perf regression introduced by SPARK-21113
> -----------------------------------------
>
> Key: SPARK-23310
> URL: https://issues.apache.org/jira/browse/SPARK-23310
> Project: Spark
> Issue Type: Bug
> Components: Spark Core
> Affects Versions: 2.3.0
> Reporter: Yin Huai
> Assignee: Sital Kedia
> Priority: Blocker
> Fix For: 2.3.0
>
>
> While running all TPC-DS queries with SF set to 1000, we noticed that Q95
> (https://github.com/databricks/spark-sql-perf/blob/master/src/main/resources/tpcds_2_4/q95.sql)
> has noticeable regression (11%). After looking into it, we found that the
> regression was introduced by SPARK-21113. Specially, ReadAheadInputStream
> gets lock congestion. After setting
> spark.unsafe.sorter.spill.read.ahead.enabled set to false, the regression
> disappear and the overall performance of all TPC-DS queries has improved.
>
> I am proposing that we set spark.unsafe.sorter.spill.read.ahead.enabled to
> false by default for Spark 2.3 and re-enable it after addressing the lock
> congestion issue.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org
For additional commands, e-mail: issues-h...@spark.apache.org
