[VL] Remove reselect build side in ShuffledHashJoinExecTransformer (#…

…5935)

backends-velox/src/main/scala/org/apache/gluten/execution/ShuffledHashJoinExecTransformer.scala

@@ -18,10 +18,9 @@ package org.apache.gluten.execution
 
 import org.apache.spark.rdd.RDD
 import org.apache.spark.sql.catalyst.expressions._
-import org.apache.spark.sql.catalyst.optimizer.{BuildLeft, BuildRight, BuildSide}
+import org.apache.spark.sql.catalyst.optimizer.BuildSide
 import org.apache.spark.sql.catalyst.plans._
-import org.apache.spark.sql.execution.{FilterExec, SparkPlan}
-import org.apache.spark.sql.execution.aggregate.BaseAggregateExec
+import org.apache.spark.sql.execution.SparkPlan
 import org.apache.spark.sql.execution.joins.BuildSideRelation
 import org.apache.spark.sql.vectorized.ColumnarBatch
 
@@ -46,80 +45,6 @@ case class ShuffledHashJoinExecTransformer(
     right,
     isSkewJoin) {
 
-  // Used to specify the preferred build side in backend's real execution.
-  object PreferredBuildSide extends Serializable {
-    val LEFT = "left table"
-    val RIGHT = "right table"
-    val NON = "none"
-  }
-
-  /**
-   * Returns whether the plan matches the condition to be preferred as build side. Currently, filter
-   * and aggregation are preferred.
-   * @param plan
-   *   the left or right plan of join
-   * @return
-   *   whether the plan matches the condition
-   */
-  private def matchCondition(plan: SparkPlan): Boolean =
-    plan.isInstanceOf[FilterExecTransformerBase] || plan.isInstanceOf[FilterExec] ||
-      plan.isInstanceOf[BaseAggregateExec]
-
-  /**
-   * Returns whether a plan is preferred as the build side. If this plan or its children match the
-   * condition, it will be preferred.
-   * @param plan
-   *   the left or right plan of join
-   * @return
-   *   whether the plan is preferred as the build side
-   */
-  private def isPreferred(plan: SparkPlan): Boolean =
-    matchCondition(plan) || plan.children.exists(child => matchCondition(child))
-
-  // Returns the preferred build side with the consideration of preferring condition.
-  private lazy val preferredBuildSide: String =
-    if ((isPreferred(left) && isPreferred(right)) || (!isPreferred(left) && !isPreferred(right))) {
-      PreferredBuildSide.NON
-    } else if (isPreferred(left)) {
-      PreferredBuildSide.LEFT
-    } else {
-      PreferredBuildSide.RIGHT
-    }
-
-  /**
-   * Returns whether the build and stream table should be exchanged with consideration of build
-   * type, planned build side and the preferred build side.
-   */
-  override lazy val needSwitchChildren: Boolean = hashJoinType match {
-    case LeftOuter | LeftSemi | ExistenceJoin(_) =>
-      joinBuildSide match {
-        case BuildLeft =>
-          // Exchange build and stream side when left side or none is preferred as the build side,
-          // and RightOuter or RightSemi wil be used.
-          !(preferredBuildSide == PreferredBuildSide.RIGHT)
-        case _ =>
-          // Do not exchange build and stream side when right side or none is preferred
-          // as the build side, and LeftOuter or LeftSemi wil be used.
-          preferredBuildSide == PreferredBuildSide.LEFT
-      }
-    case RightOuter =>
-      joinBuildSide match {
-        case BuildRight =>
-          // Do not exchange build and stream side when right side or none is preferred
-          // as the build side, and RightOuter will be used.
-          preferredBuildSide == PreferredBuildSide.LEFT
-        case _ =>
-          // Exchange build and stream side when left side or none is preferred as the build side,
-          // and LeftOuter will be used.
-          !(preferredBuildSide == PreferredBuildSide.RIGHT)
-      }
-    case _ =>
-      joinBuildSide match {
-        case BuildLeft => true
-        case BuildRight => false
-      }
-  }
-
   override protected lazy val substraitJoinType: JoinRel.JoinType = joinType match {
     case _: InnerLike =>
       JoinRel.JoinType.JOIN_TYPE_INNER