diff --git a/spark/src/main/scala/org/apache/comet/CometSparkSessionExtensions.scala b/spark/src/main/scala/org/apache/comet/CometSparkSessionExtensions.scala
index 490e0b0f26..648dc5dfbc 100644
--- a/spark/src/main/scala/org/apache/comet/CometSparkSessionExtensions.scala
+++ b/spark/src/main/scala/org/apache/comet/CometSparkSessionExtensions.scala
@@ -175,7 +175,7 @@ class CometSparkSessionExtensions
               s"Schema $requiredSchema is not supported")
             val info2 = createMessage(
               !isSchemaSupported(partitionSchema),
-              s"Schema $partitionSchema is not supported")
+              s"Partition schema $partitionSchema is not supported")
             withInfo(scanExec, Seq(info1, info2).flatten.mkString(","))
             scanExec
         }
@@ -996,6 +996,24 @@ object CometSparkSessionExtensions extends Logging {
     node
   }
 
+  /**
+   * Attaches explain information to a TreeNode, rolling up the corresponding information tags
+   * from any child nodes
+   *
+   * @param node
+   *   The node to attach the explain information to. Typically a SparkPlan
+   * @param exprs
+   *   Child nodes. Information attached in these nodes will be be included in the information
+   *   attached to @node
+   * @tparam T
+   *   The type of the TreeNode. Typically SparkPlan, AggregateExpression, or Expression
+   * @return
+   *   The node with information (if any) attached
+   */
+  def withInfo[T <: TreeNode[_]](node: T, exprs: T*): T = {
+    withInfo(node, "", exprs: _*)
+  }
+
   // Helper to reduce boilerplate
   def createMessage(condition: Boolean, message: => String): Option[String] = {
     if (condition) {
diff --git a/spark/src/main/scala/org/apache/comet/ExtendedExplainInfo.scala b/spark/src/main/scala/org/apache/comet/ExtendedExplainInfo.scala
index cbf3e76dbd..8d27501c8a 100644
--- a/spark/src/main/scala/org/apache/comet/ExtendedExplainInfo.scala
+++ b/spark/src/main/scala/org/apache/comet/ExtendedExplainInfo.scala
@@ -58,7 +58,8 @@ class ExtendedExplainInfo extends ExtendedExplainGenerator {
     info.filter(!_.contentEquals("\n"))
   }
 
-  // get all plan nodes, breadth first, leaf nodes first
+  // get all plan nodes, breadth first traversal, then returned the reversed list so
+  // leaf nodes are first
   private def sortup(node: TreeNode[_]): mutable.Queue[TreeNode[_]] = {
     val ordered = new mutable.Queue[TreeNode[_]]()
     val traversed = mutable.Queue[TreeNode[_]](getActualPlan(node))
diff --git a/spark/src/main/scala/org/apache/comet/serde/QueryPlanSerde.scala b/spark/src/main/scala/org/apache/comet/serde/QueryPlanSerde.scala
index 92ad94cd33..36aab13813 100644
--- a/spark/src/main/scala/org/apache/comet/serde/QueryPlanSerde.scala
+++ b/spark/src/main/scala/org/apache/comet/serde/QueryPlanSerde.scala
@@ -221,7 +221,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
           if (dataType.isEmpty) {
             withInfo(aggExpr, s"datatype ${s.dataType} is not supported", child)
           } else {
-            withInfo(aggExpr, null, child)
+            withInfo(aggExpr, child)
           }
           None
         }
@@ -258,7 +258,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
           withInfo(aggExpr, s"datatype ${s.dataType} is not supported", child)
           None
         } else {
-          withInfo(aggExpr, null, child)
+          withInfo(aggExpr, child)
           None
         }
       case Count(children) =>
@@ -274,7 +274,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
               .setCount(countBuilder)
               .build())
         } else {
-          withInfo(aggExpr, null, children: _*)
+          withInfo(aggExpr, children: _*)
           None
         }
       case min @ Min(child) if minMaxDataTypeSupported(min.dataType) =>
@@ -295,7 +295,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
           withInfo(aggExpr, s"datatype ${min.dataType} is not supported", child)
           None
         } else {
-          withInfo(aggExpr, null, child)
+          withInfo(aggExpr, child)
           None
         }
       case max @ Max(child) if minMaxDataTypeSupported(max.dataType) =>
@@ -316,7 +316,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
           withInfo(aggExpr, s"datatype ${max.dataType} is not supported", child)
           None
         } else {
-          withInfo(aggExpr, null, child)
+          withInfo(aggExpr, child)
           None
         }
       case first @ First(child, ignoreNulls)
@@ -338,7 +338,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
           withInfo(aggExpr, s"datatype ${first.dataType} is not supported", child)
           None
         } else {
-          withInfo(aggExpr, null, child)
+          withInfo(aggExpr, child)
           None
         }
       case last @ Last(child, ignoreNulls)
@@ -360,7 +360,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
           withInfo(aggExpr, s"datatype ${last.dataType} is not supported", child)
           None
         } else {
-          withInfo(aggExpr, null, child)
+          withInfo(aggExpr, child)
           None
         }
       case bitAnd @ BitAndAgg(child) if bitwiseAggTypeSupported(bitAnd.dataType) =>
@@ -381,7 +381,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
           withInfo(aggExpr, s"datatype ${bitAnd.dataType} is not supported", child)
           None
         } else {
-          withInfo(aggExpr, null, child)
+          withInfo(aggExpr, child)
           None
         }
       case bitOr @ BitOrAgg(child) if bitwiseAggTypeSupported(bitOr.dataType) =>
@@ -402,7 +402,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
           withInfo(aggExpr, s"datatype ${bitOr.dataType} is not supported", child)
           None
         } else {
-          withInfo(aggExpr, null, child)
+          withInfo(aggExpr, child)
           None
         }
       case bitXor @ BitXorAgg(child) if bitwiseAggTypeSupported(bitXor.dataType) =>
@@ -423,7 +423,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
           withInfo(aggExpr, s"datatype ${bitXor.dataType} is not supported", child)
           None
         } else {
-          withInfo(aggExpr, null, child)
+          withInfo(aggExpr, child)
           None
         }
       case cov @ CovSample(child1, child2, _) =>
@@ -523,7 +523,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
         case a @ Alias(_, _) =>
           val r = exprToProtoInternal(a.child, inputs)
           if (r.isEmpty) {
-            withInfo(expr, null, a.child)
+            withInfo(expr, a.child)
           }
           r
 
@@ -537,7 +537,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
           if (childExpr.isDefined) {
             castToProto(timeZoneId, dt, childExpr)
           } else {
-            withInfo(expr, null, child)
+            withInfo(expr, child)
             None
           }
 
@@ -560,7 +560,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setAdd(addBuilder)
                 .build())
           } else {
-            withInfo(add, null, left, right)
+            withInfo(add, left, right)
             None
           }
 
@@ -587,7 +587,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setSubtract(builder)
                 .build())
           } else {
-            withInfo(sub, null, left, right)
+            withInfo(sub, left, right)
             None
           }
 
@@ -615,7 +615,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setMultiply(builder)
                 .build())
           } else {
-            withInfo(mul, null, left, right)
+            withInfo(mul, left, right)
             None
           }
 
@@ -651,7 +651,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setDivide(builder)
                 .build())
           } else {
-            withInfo(div, null, left, right)
+            withInfo(div, left, right)
             None
           }
         case div @ Divide(left, right, _) =>
@@ -683,7 +683,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setRemainder(builder)
                 .build())
           } else {
-            withInfo(rem, null, left, right)
+            withInfo(rem, left, right)
             None
           }
         case rem @ Remainder(left, _, _) =>
@@ -710,7 +710,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setEq(builder)
                 .build())
           } else {
-            withInfo(expr, null, left, right)
+            withInfo(expr, left, right)
             None
           }
 
@@ -729,7 +729,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setNeq(builder)
                 .build())
           } else {
-            withInfo(expr, null, left, right)
+            withInfo(expr, left, right)
             None
           }
 
@@ -748,7 +748,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setEqNullSafe(builder)
                 .build())
           } else {
-            withInfo(expr, null, left, right)
+            withInfo(expr, left, right)
             None
           }
 
@@ -767,7 +767,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setNeqNullSafe(builder)
                 .build())
           } else {
-            withInfo(expr, null, left, right)
+            withInfo(expr, left, right)
             None
           }
 
@@ -786,7 +786,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setGt(builder)
                 .build())
           } else {
-            withInfo(expr, null, left, right)
+            withInfo(expr, left, right)
             None
           }
 
@@ -805,7 +805,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setGtEq(builder)
                 .build())
           } else {
-            withInfo(expr, null, left, right)
+            withInfo(expr, left, right)
             None
           }
 
@@ -824,7 +824,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setLt(builder)
                 .build())
           } else {
-            withInfo(expr, null, left, right)
+            withInfo(expr, left, right)
             None
           }
 
@@ -843,7 +843,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setLtEq(builder)
                 .build())
           } else {
-            withInfo(expr, null, left, right)
+            withInfo(expr, left, right)
             None
           }
 
@@ -913,7 +913,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setSubstring(builder)
                 .build())
           } else {
-            withInfo(expr, null, str)
+            withInfo(expr, str)
             None
           }
 
@@ -933,7 +933,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setLike(builder)
                 .build())
           } else {
-            withInfo(expr, null, left, right)
+            withInfo(expr, left, right)
             None
           }
 
@@ -971,7 +971,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setStartsWith(builder)
                 .build())
           } else {
-            withInfo(expr, null, left, right)
+            withInfo(expr, left, right)
             None
           }
 
@@ -990,7 +990,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setEndsWith(builder)
                 .build())
           } else {
-            withInfo(expr, null, left, right)
+            withInfo(expr, left, right)
             None
           }
 
@@ -1009,7 +1009,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setContains(builder)
                 .build())
           } else {
-            withInfo(expr, null, left, right)
+            withInfo(expr, left, right)
             None
           }
 
@@ -1026,7 +1026,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setStringSpace(builder)
                 .build())
           } else {
-            withInfo(expr, null, child)
+            withInfo(expr, child)
             None
           }
 
@@ -1046,7 +1046,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setHour(builder)
                 .build())
           } else {
-            withInfo(expr, null, child)
+            withInfo(expr, child)
             None
           }
 
@@ -1066,7 +1066,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setMinute(builder)
                 .build())
           } else {
-            withInfo(expr, null, child)
+            withInfo(expr, child)
             None
           }
 
@@ -1085,7 +1085,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setTruncDate(builder)
                 .build())
           } else {
-            withInfo(expr, null, child, format)
+            withInfo(expr, child, format)
             None
           }
 
@@ -1107,7 +1107,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setTruncTimestamp(builder)
                 .build())
           } else {
-            withInfo(expr, null, child, format)
+            withInfo(expr, child, format)
             None
           }
 
@@ -1127,7 +1127,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setSecond(builder)
                 .build())
           } else {
-            withInfo(expr, null, child)
+            withInfo(expr, child)
             None
           }
 
@@ -1161,7 +1161,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setIsNull(castBuilder)
                 .build())
           } else {
-            withInfo(expr, null, child)
+            withInfo(expr, child)
             None
           }
 
@@ -1178,7 +1178,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setIsNotNull(castBuilder)
                 .build())
           } else {
-            withInfo(expr, null, child)
+            withInfo(expr, child)
             None
           }
 
@@ -1205,7 +1205,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setSortOrder(sortOrderBuilder)
                 .build())
           } else {
-            withInfo(expr, null, child)
+            withInfo(expr, child)
             None
           }
 
@@ -1224,7 +1224,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setAnd(builder)
                 .build())
           } else {
-            withInfo(expr, null, left, right)
+            withInfo(expr, left, right)
             None
           }
 
@@ -1243,7 +1243,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setOr(builder)
                 .build())
           } else {
-            withInfo(expr, null, left, right)
+            withInfo(expr, left, right)
             None
           }
 
@@ -1270,7 +1270,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setCheckOverflow(builder)
                 .build())
           } else {
-            withInfo(expr, null, child)
+            withInfo(expr, child)
             None
           }
 
@@ -1321,7 +1321,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .build()
             Some(Expr.newBuilder().setAbs(abs).build())
           } else {
-            withInfo(expr, null, child)
+            withInfo(expr, child)
             None
           }
 
@@ -1491,7 +1491,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setIf(builder)
                 .build())
           } else {
-            withInfo(expr, null, predicate, trueValue, falseValue)
+            withInfo(expr, predicate, trueValue, falseValue)
             None
           }
 
@@ -1516,7 +1516,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
               if (elseValueExpr.isDefined) {
                 builder.setElseExpr(elseValueExpr.get)
               } else {
-                withInfo(expr, null, elseValue.get)
+                withInfo(expr, elseValue.get)
                 return None
               }
             }
@@ -1526,7 +1526,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setCaseWhen(builder)
                 .build())
           } else {
-            withInfo(expr, null, allBranches: _*)
+            withInfo(expr, allBranches: _*)
             None
           }
         case ConcatWs(children) =>
@@ -1649,7 +1649,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setBitwiseAnd(builder)
                 .build())
           } else {
-            withInfo(expr, null, left, right)
+            withInfo(expr, left, right)
             None
           }
 
@@ -1666,7 +1666,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setBitwiseNot(builder)
                 .build())
           } else {
-            withInfo(expr, null, child)
+            withInfo(expr, child)
             None
           }
 
@@ -1685,7 +1685,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setBitwiseOr(builder)
                 .build())
           } else {
-            withInfo(expr, null, left, right)
+            withInfo(expr, left, right)
             None
           }
 
@@ -1704,7 +1704,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setBitwiseXor(builder)
                 .build())
           } else {
-            withInfo(expr, null, left, right)
+            withInfo(expr, left, right)
             None
           }
 
@@ -1730,7 +1730,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setBitwiseShiftRight(builder)
                 .build())
           } else {
-            withInfo(expr, null, left, rightExpression)
+            withInfo(expr, left, rightExpression)
             None
           }
 
@@ -1756,7 +1756,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setBitwiseShiftLeft(builder)
                 .build())
           } else {
-            withInfo(expr, null, left, rightExpression)
+            withInfo(expr, left, rightExpression)
             None
           }
 
@@ -1786,7 +1786,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setNot(builder)
                 .build())
           } else {
-            withInfo(expr, null, child)
+            withInfo(expr, child)
             None
           }
 
@@ -1801,7 +1801,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setNegative(builder)
                 .build())
           } else {
-            withInfo(expr, null, child)
+            withInfo(expr, child)
             None
           }
 
@@ -1813,7 +1813,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
           if (childExpr.isDefined) {
             castToProto(None, a.dataType, childExpr)
           } else {
-            withInfo(expr, null, a.children: _*)
+            withInfo(expr, a.children: _*)
             None
           }
 
@@ -1840,7 +1840,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
 
             Some(ExprOuterClass.Expr.newBuilder().setScalarFunc(builder).build())
           } else {
-            withInfo(expr, null, arguments: _*)
+            withInfo(expr, arguments: _*)
             None
           }
 
@@ -1900,7 +1900,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
                 .setBloomFilterMightContain(builder)
                 .build())
           } else {
-            withInfo(expr, null, bloomFilter, value)
+            withInfo(expr, bloomFilter, value)
             None
           }
 
@@ -1949,7 +1949,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
             .build())
       } else {
         val allExprs = list ++ Seq(value)
-        withInfo(expr, null, allExprs: _*)
+        withInfo(expr, allExprs: _*)
         None
       }
     }
@@ -2028,7 +2028,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
             .addAllProjectList(exprs.map(_.get).asJava)
           Some(result.setProjection(projectBuilder).build())
         } else {
-          withInfo(op, null, projectList: _*)
+          withInfo(op, projectList: _*)
           None
         }
 
@@ -2039,7 +2039,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
           val filterBuilder = OperatorOuterClass.Filter.newBuilder().setPredicate(cond.get)
           Some(result.setFilter(filterBuilder).build())
         } else {
-          withInfo(op, null, condition, child)
+          withInfo(op, condition, child)
           None
         }
 
@@ -2052,7 +2052,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
             .addAllSortOrders(sortOrders.map(_.get).asJava)
           Some(result.setSort(sortBuilder).build())
         } else {
-          withInfo(op, null, sortOrder: _*)
+          withInfo(op, sortOrder: _*)
           None
         }
 
@@ -2102,7 +2102,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
             .setNumExprPerProject(projections.head.size)
           Some(result.setExpand(expandBuilder).build())
         } else {
-          withInfo(op, null, allProjExprs: _*)
+          withInfo(op, allProjExprs: _*)
           None
         }
 
@@ -2205,7 +2205,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
           } else {
             val allChildren: Seq[Expression] =
               groupingExpressions ++ aggregateExpressions ++ aggregateAttributes
-            withInfo(op, null, allChildren: _*)
+            withInfo(op, allChildren: _*)
             None
           }
         }
@@ -2231,7 +2231,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
         val condition = join.condition.map { cond =>
           val condProto = exprToProto(cond, join.left.output ++ join.right.output)
           if (condProto.isEmpty) {
-            withInfo(join, null, cond)
+            withInfo(join, cond)
             return None
           }
           condProto.get
@@ -2265,7 +2265,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
           Some(result.setHashJoin(joinBuilder).build())
         } else {
           val allExprs: Seq[Expression] = join.leftKeys ++ join.rightKeys
-          withInfo(join, null, allExprs: _*)
+          withInfo(join, allExprs: _*)
           None
         }
 
@@ -2327,7 +2327,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
           Some(result.setSortMergeJoin(joinBuilder).build())
         } else {
           val allExprs: Seq[Expression] = join.leftKeys ++ join.rightKeys
-          withInfo(join, null, allExprs: _*)
+          withInfo(join, allExprs: _*)
           None
         }
 
@@ -2487,7 +2487,7 @@ object QueryPlanSerde extends Logging with ShimQueryPlanSerde {
       childExpr: Expression*): Option[Expr] = {
     optExpr match {
       case None =>
-        withInfo(expr, null, childExpr: _*)
+        withInfo(expr, childExpr: _*)
         None
       case o => o
     }
diff --git a/spark/src/main/scala/org/apache/comet/shims/ShimCometSparkSessionExtensions.scala b/spark/src/main/scala/org/apache/comet/shims/ShimCometSparkSessionExtensions.scala
index 4291d66054..ffec1bd402 100644
--- a/spark/src/main/scala/org/apache/comet/shims/ShimCometSparkSessionExtensions.scala
+++ b/spark/src/main/scala/org/apache/comet/shims/ShimCometSparkSessionExtensions.scala
@@ -50,6 +50,8 @@ object ShimCometSparkSessionExtensions {
     .map(_.asInstanceOf[Int])
     .headOption
 
+  // Extended info is available only since Spark 4.0.0
+  // (https://issues.apache.org/jira/browse/SPARK-47289)
   def supportsExtendedExplainInfo(qe: QueryExecution): Boolean = {
     try {
       // Look for QueryExecution.extendedExplainInfo(scala.Function1[String, Unit], SparkPlan)
diff --git a/spark/src/main/scala/org/apache/spark/sql/ExtendedExplainGenerator.scala b/spark/src/main/scala/org/apache/spark/sql/ExtendedExplainGenerator.scala
index e72c894b3d..3c5ae95e29 100644
--- a/spark/src/main/scala/org/apache/spark/sql/ExtendedExplainGenerator.scala
+++ b/spark/src/main/scala/org/apache/spark/sql/ExtendedExplainGenerator.scala
@@ -23,6 +23,8 @@ import org.apache.spark.sql.execution.SparkPlan
 
 /**
  * A trait for a session extension to implement that provides addition explain plan information.
+ * We copy this from Spark 4.0 since this trait is not available in Spark 3.x. We can remove this
+ * after dropping Spark 3.x support.
  */
 
 trait ExtendedExplainGenerator {
diff --git a/spark/src/test/scala/org/apache/spark/sql/CometTPCQueryListBase.scala b/spark/src/test/scala/org/apache/spark/sql/CometTPCQueryListBase.scala
index a008dbd58e..6a58320606 100644
--- a/spark/src/test/scala/org/apache/spark/sql/CometTPCQueryListBase.scala
+++ b/spark/src/test/scala/org/apache/spark/sql/CometTPCQueryListBase.scala
@@ -88,6 +88,7 @@ trait CometTPCQueryListBase
         CometConf.COMET_EXEC_ENABLED.key -> "true",
         CometConf.COMET_EXEC_SHUFFLE_ENABLED.key -> "true",
         CometConf.COMET_EXEC_ALL_OPERATOR_ENABLED.key -> "true",
+        // Lower bloom filter thresholds to allows us to simulate the plan produced at larger scale.
         "spark.sql.optimizer.runtime.bloomFilter.creationSideThreshold" -> "1MB",
         "spark.sql.optimizer.runtime.bloomFilter.applicationSideScanSizeThreshold" -> "1MB") {