[SPARK-30842][SQL] Adjust abstraction structure for join operators

sql/core/src/main/scala/org/apache/spark/sql/execution/joins/BaseJoinExec.scala

@@ -0,0 +1,56 @@
+/*
+ * 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.joins
+
+import org.apache.spark.sql.catalyst.expressions.Expression
+import org.apache.spark.sql.catalyst.plans.JoinType
+import org.apache.spark.sql.execution.{BinaryExecNode, ExplainUtils}
+
+/**
+ * Holds common logic for join operators
+ */
+trait BaseJoinExec extends BinaryExecNode {
+  def joinType: JoinType
+  def condition: Option[Expression]
+  def leftKeys: Seq[Expression]
+  def rightKeys: Seq[Expression]
+
+  override def simpleStringWithNodeId(): String = {
+    val opId = ExplainUtils.getOpId(this)
+    s"$nodeName $joinType ($opId)".trim
+  }
+
+  override def verboseStringWithOperatorId(): String = {
+    val joinCondStr = if (condition.isDefined) {
+      s"${condition.get}"
+    } else "None"
+    if (leftKeys.nonEmpty || rightKeys.nonEmpty) {
+      s"""
+         |(${ExplainUtils.getOpId(this)}) $nodeName ${ExplainUtils.getCodegenId(this)}
+         |${ExplainUtils.generateFieldString("Left keys", leftKeys)}
+         |${ExplainUtils.generateFieldString("Right keys", rightKeys)}
+         |${ExplainUtils.generateFieldString("Join condition", joinCondStr)}
+       """.stripMargin
+    } else {
+      s"""
+         |(${ExplainUtils.getOpId(this)}) $nodeName ${ExplainUtils.getCodegenId(this)}
+         |${ExplainUtils.generateFieldString("Join condition", joinCondStr)}
+       """.stripMargin
+    }
+  }
+}

sql/core/src/main/scala/org/apache/spark/sql/execution/joins/BroadcastHashJoinExec.scala

@@ -26,7 +26,7 @@ import org.apache.spark.sql.catalyst.expressions.codegen._
 import org.apache.spark.sql.catalyst.expressions.codegen.Block._
 import org.apache.spark.sql.catalyst.plans._
 import org.apache.spark.sql.catalyst.plans.physical.{BroadcastDistribution, Distribution, UnspecifiedDistribution}
-import org.apache.spark.sql.execution.{BinaryExecNode, CodegenSupport, SparkPlan}
+import org.apache.spark.sql.execution.{CodegenSupport, SparkPlan}
 import org.apache.spark.sql.execution.metric.SQLMetrics
 import org.apache.spark.sql.types.{BooleanType, LongType}
 
@@ -44,7 +44,7 @@ case class BroadcastHashJoinExec(
     condition: Option[Expression],
     left: SparkPlan,
     right: SparkPlan)
-  extends BinaryExecNode with HashJoin with CodegenSupport {
+  extends HashJoin with CodegenSupport {
 
   override lazy val metrics = Map(
     "numOutputRows" -> SQLMetrics.createMetric(sparkContext, "number of output rows"))

sql/core/src/main/scala/org/apache/spark/sql/execution/joins/BroadcastNestedLoopJoinExec.scala

@@ -23,7 +23,7 @@ import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.catalyst.expressions._
 import org.apache.spark.sql.catalyst.plans._
 import org.apache.spark.sql.catalyst.plans.physical._
-import org.apache.spark.sql.execution.{BinaryExecNode, SparkPlan}
+import org.apache.spark.sql.execution.{ExplainUtils, SparkPlan}
 import org.apache.spark.sql.execution.metric.SQLMetrics
 import org.apache.spark.util.collection.{BitSet, CompactBuffer}
 
@@ -32,7 +32,10 @@ case class BroadcastNestedLoopJoinExec(
     right: SparkPlan,
     buildSide: BuildSide,
     joinType: JoinType,
-    condition: Option[Expression]) extends BinaryExecNode {
+    condition: Option[Expression]) extends BaseJoinExec {
+
+  override def leftKeys: Seq[Expression] = Nil
+  override def rightKeys: Seq[Expression] = Nil
 
   override lazy val metrics = Map(
     "numOutputRows" -> SQLMetrics.createMetric(sparkContext, "number of output rows"))
@@ -43,6 +46,11 @@ case class BroadcastNestedLoopJoinExec(
     case BuildLeft => (right, left)
   }
 
+  override def simpleStringWithNodeId(): String = {
+    val opId = ExplainUtils.getOpId(this)
+    s"$nodeName $joinType ${buildSide} ($opId)".trim
+  }
+
   override def requiredChildDistribution: Seq[Distribution] = buildSide match {
     case BuildLeft =>
       BroadcastDistribution(IdentityBroadcastMode) :: UnspecifiedDistribution :: Nil

sql/core/src/main/scala/org/apache/spark/sql/execution/joins/CartesianProductExec.scala

@@ -22,7 +22,8 @@ import org.apache.spark.rdd.{CartesianPartition, CartesianRDD, RDD}
 import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.catalyst.expressions.{Attribute, Expression, JoinedRow, Predicate, UnsafeRow}
 import org.apache.spark.sql.catalyst.expressions.codegen.GenerateUnsafeRowJoiner
-import org.apache.spark.sql.execution.{BinaryExecNode, ExplainUtils, ExternalAppendOnlyUnsafeRowArray, SparkPlan}
+import org.apache.spark.sql.catalyst.plans.{Inner, JoinType}
+import org.apache.spark.sql.execution.{ExternalAppendOnlyUnsafeRowArray, SparkPlan}
 import org.apache.spark.sql.execution.metric.SQLMetrics
 import org.apache.spark.util.CompletionIterator
 
@@ -60,23 +61,17 @@ class UnsafeCartesianRDD(
 case class CartesianProductExec(
     left: SparkPlan,
     right: SparkPlan,
-    condition: Option[Expression]) extends BinaryExecNode {
+    condition: Option[Expression]) extends BaseJoinExec {
+
+  override def joinType: JoinType = Inner
+  override def leftKeys: Seq[Expression] = Nil
+  override def rightKeys: Seq[Expression] = Nil
+
   override def output: Seq[Attribute] = left.output ++ right.output
 
   override lazy val metrics = Map(
     "numOutputRows" -> SQLMetrics.createMetric(sparkContext, "number of output rows"))
 
-  override def verboseStringWithOperatorId(): String = {
-    val joinCondStr = if (condition.isDefined) {
-      s"${condition.get}"
-    } else "None"
-
-    s"""
-       |(${ExplainUtils.getOpId(this)}) $nodeName ${ExplainUtils.getCodegenId(this)}
-       |${ExplainUtils.generateFieldString("Join condition", joinCondStr)}
-     """.stripMargin
-  }
-
   protected override def doExecute(): RDD[InternalRow] = {
     val numOutputRows = longMetric("numOutputRows")
 

sql/core/src/main/scala/org/apache/spark/sql/execution/joins/HashJoin.scala

@@ -22,39 +22,18 @@ import org.apache.spark.sql.catalyst.expressions._
 import org.apache.spark.sql.catalyst.expressions.BindReferences.bindReferences
 import org.apache.spark.sql.catalyst.plans._
 import org.apache.spark.sql.catalyst.plans.physical.Partitioning
-import org.apache.spark.sql.execution.{ExplainUtils, RowIterator, SparkPlan}
+import org.apache.spark.sql.execution.{ExplainUtils, RowIterator}
 import org.apache.spark.sql.execution.metric.SQLMetric
 import org.apache.spark.sql.types.{IntegralType, LongType}
 
-trait HashJoin {
-  self: SparkPlan =>
-
-  def leftKeys: Seq[Expression]
-  def rightKeys: Seq[Expression]
-  def joinType: JoinType
+trait HashJoin extends BaseJoinExec {
   def buildSide: BuildSide
-  def condition: Option[Expression]
-  def left: SparkPlan
-  def right: SparkPlan
 
   override def simpleStringWithNodeId(): String = {
     val opId = ExplainUtils.getOpId(this)
     s"$nodeName $joinType ${buildSide} ($opId)".trim
   }
 
-  override def verboseStringWithOperatorId(): String = {
-    val joinCondStr = if (condition.isDefined) {
-      s"${condition.get}"
-    } else "None"
-
-    s"""
-       |(${ExplainUtils.getOpId(this)}) $nodeName ${ExplainUtils.getCodegenId(this)}
-       |${ExplainUtils.generateFieldString("Left keys", leftKeys)}
-       |${ExplainUtils.generateFieldString("Right keys", rightKeys)}
-       |${ExplainUtils.generateFieldString("Join condition", joinCondStr)}
-     """.stripMargin
-  }
-
   override def output: Seq[Attribute] = {
     joinType match {
       case _: InnerLike =>

sql/core/src/main/scala/org/apache/spark/sql/execution/joins/ShuffledHashJoinExec.scala

@@ -25,7 +25,7 @@ import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.catalyst.expressions.Expression
 import org.apache.spark.sql.catalyst.plans._
 import org.apache.spark.sql.catalyst.plans.physical._
-import org.apache.spark.sql.execution.{BinaryExecNode, SparkPlan}
+import org.apache.spark.sql.execution.SparkPlan
 import org.apache.spark.sql.execution.metric.SQLMetrics
 
 /**
@@ -39,7 +39,7 @@ case class ShuffledHashJoinExec(
     condition: Option[Expression],
     left: SparkPlan,
     right: SparkPlan)
-  extends BinaryExecNode with HashJoin {
+  extends HashJoin {
 
   override lazy val metrics = Map(
     "numOutputRows" -> SQLMetrics.createMetric(sparkContext, "number of output rows"),

sql/core/src/main/scala/org/apache/spark/sql/execution/joins/SortMergeJoinExec.scala

@@ -41,7 +41,7 @@ case class SortMergeJoinExec(
     condition: Option[Expression],
     left: SparkPlan,
     right: SparkPlan,
-    isSkewJoin: Boolean = false) extends BinaryExecNode with CodegenSupport {
+    isSkewJoin: Boolean = false) extends BaseJoinExec with CodegenSupport {
 
   override lazy val metrics = Map(
     "numOutputRows" -> SQLMetrics.createMetric(sparkContext, "number of output rows"))
@@ -52,23 +52,6 @@ case class SortMergeJoinExec(
 
   override def stringArgs: Iterator[Any] = super.stringArgs.toSeq.dropRight(1).iterator
 
-  override def simpleStringWithNodeId(): String = {
-    val opId = ExplainUtils.getOpId(this)
-    s"$nodeName $joinType ($opId)".trim
-  }
-
-  override def verboseStringWithOperatorId(): String = {
-    val joinCondStr = if (condition.isDefined) {
-      s"${condition.get}"
-    } else "None"
-    s"""
-       |(${ExplainUtils.getOpId(this)}) $nodeName ${ExplainUtils.getCodegenId(this)}
-       |${ExplainUtils.generateFieldString("Left keys", leftKeys)}
-       |${ExplainUtils.generateFieldString("Right keys", rightKeys)}
-       |${ExplainUtils.generateFieldString("Join condition", joinCondStr)}
-     """.stripMargin
-  }
-
   override def output: Seq[Attribute] = {
     joinType match {
       case _: InnerLike =>