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Posted to issues@spark.apache.org by "Shardul Mahadik (Jira)" <ji...@apache.org> on 2022/12/16 18:28:00 UTC
[jira] [Comment Edited] (SPARK-41162) Anti-join must not be pushed below aggregation with ambiguous predicates
[ https://issues.apache.org/jira/browse/SPARK-41162?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17648751#comment-17648751 ]
Shardul Mahadik edited comment on SPARK-41162 at 12/16/22 6:27 PM:
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[~cloud_fan] Can you help take a look at this? This is a correctness issue and affects not just master but also 3.1+ if I am not wrong. We hit this issue in production with one of our user jobs.
was (Author: shardulm):
[~cloud_fan] Can you help take a look at this? This is a correctness issue affects not just master but also 3.1+ if I am not wrong. We hit this issue in production with one of our user jobs.
> Anti-join must not be pushed below aggregation with ambiguous predicates
> ------------------------------------------------------------------------
>
> Key: SPARK-41162
> URL: https://issues.apache.org/jira/browse/SPARK-41162
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 3.4.0
> Reporter: Enrico Minack
> Priority: Major
>
> The following query should return a single row as all values for {{id}} except for the largest will be eliminated by the anti-join:
> {code}
> val ids = Seq(1, 2, 3).toDF("id").distinct()
> val result = ids.withColumn("id", $"id" + 1).join(ids, "id", "left_anti").collect()
> assert(result.length == 1)
> {code}
> Without the {{distinct()}}, the assertion is true. With {{distinct()}}, the assertion should still hold but is false.
> Rule {{PushDownLeftSemiAntiJoin}} pushes the {{Join}} below the left {{Aggregate}} with join condition {{(id#750 + 1) = id#750}}, which can never be true.
> {code}
> === Applying Rule org.apache.spark.sql.catalyst.optimizer.PushDownLeftSemiAntiJoin ===
> !Join LeftAnti, (id#752 = id#750) 'Aggregate [id#750], [(id#750 + 1) AS id#752]
> !:- Aggregate [id#750], [(id#750 + 1) AS id#752] +- 'Join LeftAnti, ((id#750 + 1) = id#750)
> !: +- LocalRelation [id#750] :- LocalRelation [id#750]
> !+- Aggregate [id#750], [id#750] +- Aggregate [id#750], [id#750]
> ! +- LocalRelation [id#750] +- LocalRelation [id#750]
> {code}
> The optimizer then rightly removes the left-anti join altogether, returning the left child only.
> Rule {{PushDownLeftSemiAntiJoin}} should not push down predicates that reference left *and* right child.
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