diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/AliasAwareOutputExpression.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/AliasAwareOutputExpression.scala
index 6fca19fbf0a90..7d0afa8bb676a 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/AliasAwareOutputExpression.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/AliasAwareOutputExpression.scala
@@ -29,9 +29,14 @@ import org.apache.spark.sql.catalyst.trees.MultiTransform
  */
 trait PartitioningPreservingUnaryExecNode extends UnaryExecNode
   with AliasAwareOutputExpression {
-  final override def outputPartitioning: Partitioning = {
+  // A `lazy val` because the planner asks a node for its partitioning many times, and this body
+  // projects every partitioning expression through the output aliases, and for a
+  // `KeyedPartitioning` child also builds an `ExpressionSet` per key position and cross-products
+  // the per-position alternatives. Read no live config here, or memoizing would freeze it.
+  @transient final override lazy val outputPartitioning: Partitioning = {
+    val childPartitioning = child.outputPartitioning
     val (keyedPartitionings, otherPartitionings) =
-      PartitioningCollection.flatten(child.outputPartitioning)
+      PartitioningCollection.flatten(childPartitioning)
         .partition(_.isInstanceOf[KeyedPartitioning])
 
     val projectedKPs =
@@ -44,7 +49,7 @@ trait PartitioningPreservingUnaryExecNode extends UnaryExecNode
     // deep projection chain that nesting overflows the stack when the partitioning is later
     // serialized or deeply traversed.
     (projectedKPs ++ projectedOthers).take(aliasCandidateLimit).toList match {
-      case Seq() => UnknownPartitioning(child.outputPartitioning.numPartitions)
+      case Seq() => UnknownPartitioning(childPartitioning.numPartitions)
       case Seq(p) => p
       case ps => PartitioningCollection.fromPartitionings(ps)
     }
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/v2/GroupPartitionsExec.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/v2/GroupPartitionsExec.scala
index eb0142c5a01bd..c785218f49989 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/v2/GroupPartitionsExec.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/v2/GroupPartitionsExec.scala
@@ -67,7 +67,10 @@ case class GroupPartitionsExec(
     @transient enableSortedMerge: Boolean = false
   ) extends UnaryExecNode {
 
-  override def outputPartitioning: Partitioning = {
+  // A `lazy val` because the planner asks a node for its partitioning many times, and this body
+  // rebuilds every `KeyedPartitioning` in the child's on top of the already memoized `grouping`.
+  // Read no live config here, or memoizing would freeze it.
+  @transient override lazy val outputPartitioning: Partitioning = {
     child.outputPartitioning match {
       case p: Partitioning with Expression =>
         // There can be multiple `KeyedPartitioning`s in an output partitioning of a join, but they