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https://issues.apache.org/jira/browse/SPARK-32143?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17149098#comment-17149098
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Apache Spark commented on SPARK-32143:
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User 'LantaoJin' has created a pull request for this issue:
https://github.com/apache/spark/pull/28961
> Fast fail when the AQE skew join produce too many splits
> --------------------------------------------------------
>
> Key: SPARK-32143
> URL: https://issues.apache.org/jira/browse/SPARK-32143
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 3.0.0, 3.1.0
> Reporter: Lantao Jin
> Priority: Major
>
> In handling skewed SortMergeJoin, when matching partitions from the left side
> and the right side both have skew and split too many partitions, the plan
> generation may take a very long time.
> Even fallback to normal SMJ, the query cannot success either. So we should
> fast fail this query.
> In below logs we can see that it took over 1 hour to generate the plan in AQE
> when handle a skewed join which produced too many splits.
> {quote}20/06/30 *12:31:26,271* INFO [HiveServer2-Background-Pool:
> Thread-821384] adaptive.OptimizeSkewedJoin:54 :
> 20/06/30 12:31:26,299 INFO [HiveServer2-Background-Pool: Thread-821384]
> adaptive.OptimizeSkewedJoin:54 : Left side partition 1 (3 TB) is skewed,
> split it into *39150* parts.
> 20/06/30 12:31:26,315 INFO [HiveServer2-Background-Pool: Thread-821384]
> adaptive.OptimizeSkewedJoin:54 : Right side partition 1 (11 TB) is skewed,
> split it into *17022* parts.
> 20/06/30 12:32:24,952 INFO [HiveServer2-Background-Pool: Thread-821384]
> adaptive.OptimizeSkewedJoin:54 : Right side partition 8 (1 GB) is skewed,
> split it into 17 parts.
> ...
> 20/06/30 *13:27:25,158* INFO [HiveServer2-Background-Pool: Thread-821384]
> adaptive.AdaptiveSparkPlanExec:54 : Final plan: CollectLimit 1000
> {quote}
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