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Update SortMergeJoinExec.scala #18836

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BoleynSu wants to merge 1 commit into from
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Update SortMergeJoinExec.scala #18836

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2 changes: 1 addition & 1 deletion sql/core/src/main/scala/org/apache/spark/sql/execution/joins/SortMergeJoinExec.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -82,7 +82,7 @@ case class SortMergeJoinExec(

override def outputOrdering: Seq[SortOrder] = joinType match {
// For inner join, orders of both sides keys should be kept.
case Inner =>
case _: InnerLike =>
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@hvanhovell hvanhovell Aug 3, 2017

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Can someone explain to me what is being fixed here? The other InnerLike variant, Cross, does not get planned using a SortMergeJoin.

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@BoleynSu BoleynSu Aug 4, 2017

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I think we can get a SortMergeJoin paln with Cross, e.g. select distinct a.i + 1,a.* from T a cross join T t where a.i > 1 and t.i = a.i group by a.i having a.i > 2.

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@gatorsmile gatorsmile Aug 7, 2017

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Even worse, this could cause an exception

val df = Seq((1, 1)).toDF("i", "j")
df.createOrReplaceTempView("T")
withSQLConf(SQLConf.AUTO_BROADCASTJOIN_THRESHOLD.key -> "-1") {
  sql("select * from (select a.i from T a cross join T t where t.i = a.i) as t1 " +
    "cross join T t2 where t2.i = t1.i").explain(true)
}

It will return the following error:

SortMergeJoinExec should not take Cross as the JoinType
java.lang.IllegalArgumentException: SortMergeJoinExec should not take Cross as the JoinType
	at org.apache.spark.sql.execution.joins.SortMergeJoinExec.outputOrdering(SortMergeJoinExec.scala:100)
	at org.apache.spark.sql.execution.ProjectExec

We need to backport it to 2.2

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@hvanhovell hvanhovell Aug 7, 2017

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Yeah that makes sense

val leftKeyOrdering = getKeyOrdering(leftKeys, left.outputOrdering)
val rightKeyOrdering = getKeyOrdering(rightKeys, right.outputOrdering)
leftKeyOrdering.zip(rightKeyOrdering).map { case (lKey, rKey) =>
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