[SPARK-32282][SQL] Improve EnsureRquirement.reorderJoinKeys to handle more scenarios such as PartitioningCollection

sql/core/src/main/scala/org/apache/spark/sql/execution/exchange/EnsureRequirements.scala

@@ -135,9 +135,14 @@ case class EnsureRequirements(conf: SQLConf) extends Rule[SparkPlan] {
       leftKeys: IndexedSeq[Expression],
       rightKeys: IndexedSeq[Expression],
       expectedOrderOfKeys: Seq[Expression],
-      currentOrderOfKeys: Seq[Expression]): (Seq[Expression], Seq[Expression]) = {
+      currentOrderOfKeys: Seq[Expression]): Option[(Seq[Expression], Seq[Expression])] = {
     if (expectedOrderOfKeys.size != currentOrderOfKeys.size) {
-      return (leftKeys, rightKeys)
+      return None
+    }
+
+    // Check if the current order already satisfies the expected order.
+    if (expectedOrderOfKeys.zip(currentOrderOfKeys).forall(p => p._1.semanticEquals(p._2))) {
+      return Some(leftKeys, rightKeys)
     }
 
     // Build a lookup between an expression and the positions its holds in the current key seq.
@@ -164,10 +169,10 @@ case class EnsureRequirements(conf: SQLConf) extends Rule[SparkPlan] {
           rightKeysBuffer += rightKeys(index)
         case _ =>
           // The expression cannot be found, or we have exhausted all indices for that expression.
-          return (leftKeys, rightKeys)
+          return None
       }
     }
-    (leftKeysBuffer.toSeq, rightKeysBuffer.toSeq)
+    Some(leftKeysBuffer.toSeq, rightKeysBuffer.toSeq)
   }
 
   private def reorderJoinKeys(
@@ -176,19 +181,48 @@ case class EnsureRequirements(conf: SQLConf) extends Rule[SparkPlan] {
       leftPartitioning: Partitioning,
       rightPartitioning: Partitioning): (Seq[Expression], Seq[Expression]) = {
     if (leftKeys.forall(_.deterministic) && rightKeys.forall(_.deterministic)) {
-      (leftPartitioning, rightPartitioning) match {
-        case (HashPartitioning(leftExpressions, _), _) =>
-          reorder(leftKeys.toIndexedSeq, rightKeys.toIndexedSeq, leftExpressions, leftKeys)
-        case (_, HashPartitioning(rightExpressions, _)) =>
-          reorder(leftKeys.toIndexedSeq, rightKeys.toIndexedSeq, rightExpressions, rightKeys)
-        case _ =>
-          (leftKeys, rightKeys)
-      }
+      reorderJoinKeysRecursively(
+        leftKeys,
+        rightKeys,
+        Some(leftPartitioning),
+        Some(rightPartitioning))
+        .getOrElse((leftKeys, rightKeys))
     } else {
       (leftKeys, rightKeys)
     }
   }
 
+  /**
+   * Recursively reorders the join keys based on partitioning. It starts reordering the
+   * join keys to match HashPartitioning on either side, followed by PartitioningCollection.
+   */
+  private def reorderJoinKeysRecursively(
+      leftKeys: Seq[Expression],
+      rightKeys: Seq[Expression],
+      leftPartitioning: Option[Partitioning],
+      rightPartitioning: Option[Partitioning]): Option[(Seq[Expression], Seq[Expression])] = {
+    (leftPartitioning, rightPartitioning) match {
+      case (Some(HashPartitioning(leftExpressions, _)), _) =>
+        reorder(leftKeys.toIndexedSeq, rightKeys.toIndexedSeq, leftExpressions, leftKeys)
+          .orElse(reorderJoinKeysRecursively(
+            leftKeys, rightKeys, None, rightPartitioning))
+      case (_, Some(HashPartitioning(rightExpressions, _))) =>
+        reorder(leftKeys.toIndexedSeq, rightKeys.toIndexedSeq, rightExpressions, rightKeys)
+          .orElse(reorderJoinKeysRecursively(
+            leftKeys, rightKeys, leftPartitioning, None))
+      case (Some(PartitioningCollection(partitionings)), _) =>
+        partitionings.foldLeft(Option.empty[(Seq[Expression], Seq[Expression])]) { (res, p) =>
+          res.orElse(reorderJoinKeysRecursively(leftKeys, rightKeys, Some(p), rightPartitioning))
+        }.orElse(reorderJoinKeysRecursively(leftKeys, rightKeys, None, rightPartitioning))
+      case (_, Some(PartitioningCollection(partitionings))) =>
+        partitionings.foldLeft(Option.empty[(Seq[Expression], Seq[Expression])]) { (res, p) =>
+          res.orElse(reorderJoinKeysRecursively(leftKeys, rightKeys, leftPartitioning, Some(p)))
+        }.orElse(None)
+      case _ =>
+        None
+    }
+  }
+
   /**
    * When the physical operators are created for JOIN, the ordering of join keys is based on order
    * in which the join keys appear in the user query. That might not match with the output

sql/core/src/test/scala/org/apache/spark/sql/execution/exchange/EnsureRequirementsSuite.scala

@@ -0,0 +1,122 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.sql.execution.exchange
+
+import org.apache.spark.sql.catalyst.expressions.Literal
+import org.apache.spark.sql.catalyst.plans.Inner
+import org.apache.spark.sql.catalyst.plans.physical.{HashPartitioning, PartitioningCollection}
+import org.apache.spark.sql.execution.{DummySparkPlan, SortExec}
+import org.apache.spark.sql.execution.joins.SortMergeJoinExec
+import org.apache.spark.sql.test.SharedSparkSession
+
+class EnsureRequirementsSuite extends SharedSparkSession {
+  private val exprA = Literal(1)
+  private val exprB = Literal(2)
+  private val exprC = Literal(3)
+
+  test("reorder should handle PartitioningCollection") {
+    val plan1 = DummySparkPlan(
+      outputPartitioning = PartitioningCollection(Seq(
+        HashPartitioning(exprA :: exprB :: Nil, 5),
+        HashPartitioning(exprA :: Nil, 5))))
+    val plan2 = DummySparkPlan()
+
+    // Test PartitioningCollection on the left side of join.
+    val smjExec1 = SortMergeJoinExec(
+      exprB :: exprA :: Nil, exprA :: exprB :: Nil, Inner, None, plan1, plan2)
+    EnsureRequirements(spark.sessionState.conf).apply(smjExec1) match {
+      case SortMergeJoinExec(leftKeys, rightKeys, _, _,
+        SortExec(_, _, DummySparkPlan(_, _, _: PartitioningCollection, _, _), _),
+        SortExec(_, _, ShuffleExchangeExec(_: HashPartitioning, _, _), _), _) =>
+        assert(leftKeys === Seq(exprA, exprB))
+        assert(rightKeys === Seq(exprB, exprA))
+      case other => fail(other.toString)
+    }
+
+    // Test PartitioningCollection on the right side of join.
+    val smjExec2 = SortMergeJoinExec(
+      exprA :: exprB :: Nil, exprB :: exprA :: Nil, Inner, None, plan2, plan1)
+    EnsureRequirements(spark.sessionState.conf).apply(smjExec2) match {
+      case SortMergeJoinExec(leftKeys, rightKeys, _, _,
+        SortExec(_, _, ShuffleExchangeExec(_: HashPartitioning, _, _), _),
+        SortExec(_, _, DummySparkPlan(_, _, _: PartitioningCollection, _, _), _), _) =>
+        assert(leftKeys === Seq(exprB, exprA))
+        assert(rightKeys === Seq(exprA, exprB))
+      case other => fail(other.toString)
+    }
+
+    // Both sides are PartitioningCollection, but left side cannot be reorderd to match
+    // and it should fall back to the right side.
+    val smjExec3 = SortMergeJoinExec(
+      exprA :: exprC :: Nil, exprB :: exprA :: Nil, Inner, None, plan1, plan1)
+    EnsureRequirements(spark.sessionState.conf).apply(smjExec3) match {
+      case SortMergeJoinExec(leftKeys, rightKeys, _, _,
+        SortExec(_, _, ShuffleExchangeExec(_: HashPartitioning, _, _), _),
+        SortExec(_, _, DummySparkPlan(_, _, _: PartitioningCollection, _, _), _), _) =>
+        assert(leftKeys === Seq(exprC, exprA))
+        assert(rightKeys === Seq(exprA, exprB))
+      case other => fail(other.toString)
+    }
+  }
+
+  test("reorder should fallback to the other side partitioning") {
+    val plan1 = DummySparkPlan(
+      outputPartitioning = HashPartitioning(exprA :: exprB :: exprC :: Nil, 5))
+    val plan2 = DummySparkPlan(
+      outputPartitioning = HashPartitioning(exprB :: exprC :: Nil, 5))
+
+    // Test fallback to the right side, which has HashPartitioning.
+    val smjExec1 = SortMergeJoinExec(
+      exprA :: exprB :: Nil, exprC :: exprB :: Nil, Inner, None, plan1, plan2)
+    EnsureRequirements(spark.sessionState.conf).apply(smjExec1) match {
+      case SortMergeJoinExec(leftKeys, rightKeys, _, _,
+        SortExec(_, _, ShuffleExchangeExec(_: HashPartitioning, _, _), _),
+        SortExec(_, _, DummySparkPlan(_, _, _: HashPartitioning, _, _), _), _) =>
+        assert(leftKeys === Seq(exprB, exprA))
+        assert(rightKeys === Seq(exprB, exprC))
+      case other => fail(other.toString)
+    }
+
+    // Test fallback to the right side, which has PartitioningCollection.
+    val plan3 = DummySparkPlan(
+      outputPartitioning = PartitioningCollection(Seq(HashPartitioning(exprB :: exprC :: Nil, 5))))
+    val smjExec2 = SortMergeJoinExec(
+      exprA :: exprB :: Nil, exprC :: exprB :: Nil, Inner, None, plan1, plan3)
+    EnsureRequirements(spark.sessionState.conf).apply(smjExec2) match {
+      case SortMergeJoinExec(leftKeys, rightKeys, _, _,
+        SortExec(_, _, ShuffleExchangeExec(_: HashPartitioning, _, _), _),
+        SortExec(_, _, DummySparkPlan(_, _, _: PartitioningCollection, _, _), _), _) =>
+        assert(leftKeys === Seq(exprB, exprA))
+        assert(rightKeys === Seq(exprB, exprC))
+      case other => fail(other.toString)
+    }
+
+    // The right side has HashPartitioning, so it is matched first, but no reordering match is
+    // found, and it should fall back to the left side, which has a PartitioningCollection.
+    val smjExec3 = SortMergeJoinExec(
+      exprC :: exprB :: Nil, exprA :: exprB :: Nil, Inner, None, plan3, plan1)
+    EnsureRequirements(spark.sessionState.conf).apply(smjExec3) match {
+      case SortMergeJoinExec(leftKeys, rightKeys, _, _,
+        SortExec(_, _, DummySparkPlan(_, _, _: PartitioningCollection, _, _), _),
+        SortExec(_, _, ShuffleExchangeExec(_: HashPartitioning, _, _), _), _) =>
+        assert(leftKeys === Seq(exprB, exprC))
+        assert(rightKeys === Seq(exprB, exprA))
+      case other => fail(other.toString)
+    }
+  }
+}