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https://issues.apache.org/jira/browse/SPARK-59887?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated SPARK-59887:
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Labels: pull-request-available (was: )
> Fix wrong results when a storage-partitioned join pairs a transform of a
> join-key expression with one of a column
> -----------------------------------------------------------------------------------------------------------------
>
> Key: SPARK-59887
> URL: https://issues.apache.org/jira/browse/SPARK-59887
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 5.0.0
> Reporter: Peter Toth
> Priority: Major
> Labels: pull-request-available
>
> With {{spark.sql.sources.v2.bucketing.shuffle.enabled}} on, a
> storage-partitioned join can return wrong results when a side that was
> shuffled onto a transform of a join-key expression meets another bucketed
> table in a later join.
> Repro, with AQE and broadcast joins off. {{t1(id bigint)}} and {{t3(x
> bigint)}} are partitioned by {{bucket(4, ...)}}, {{plain(b bigint)}} is not
> partitioned, and each holds the values 0 to 7:
> {code:sql}
> SELECT t1.id, p.b, t3.x FROM t1
> JOIN plain p ON t1.id = p.b + 1
> JOIN t3 ON p.b = t3.x
> {code}
> The query should return 7 rows. It returns 0, and the second join has no
> shuffle.
> Why:
> * The first join shuffles {{plain}} onto {{t1}}'s partitioning.
> {{KeyedShuffleSpec.createPartitioning}} builds that partitioning from
> {{plain}}'s join key, so it is {{bucket(4, b + 1)}}.
> * The second join clusters {{plain}} on the bare {{b}}.
> {{KeyedShuffleSpec.keyPositions}} maps a partition expression to a cluster
> key by its reference, so {{bucket(4, b + 1)}} counts as a function of {{b}},
> the counterpart of {{x}}.
> * {{TransformExpression.isSameFunction}} compares only the function name and
> the bucket count, so {{bucket(4, b + 1)}} is the same as {{t3}}'s {{bucket(4,
> x)}}, and the join pairs the partitions as they stand. A row with {{b = x}}
> sits in bucket {{(b + 1) % 4}} on one side and in {{x % 4}} on the other.
> Measured on master. The one-side shuffle of transform expressions came with
> SPARK-48012 (4.0.0).
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