diff --git a/src/backend/executor/nodeBitmapHeapscan.c b/src/backend/executor/nodeBitmapHeapscan.c
index f7e55e0b45..6035b4dfd4 100644
--- a/src/backend/executor/nodeBitmapHeapscan.c
+++ b/src/backend/executor/nodeBitmapHeapscan.c
@@ -934,7 +934,8 @@ BitmapShouldInitializeSharedState(ParallelBitmapHeapState *pstate)
 /* ----------------------------------------------------------------
  *		ExecBitmapHeapEstimate
  *
- *		estimates the space required to serialize bitmap scan node.
+ *		Compute the amount of space we'll need in the parallel
+ *		query DSM, and inform pcxt->estimator about our needs.
  * ----------------------------------------------------------------
  */
 void
diff --git a/src/backend/executor/nodeIndexonlyscan.c b/src/backend/executor/nodeIndexonlyscan.c
index 5351cb8981..9368ca04f8 100644
--- a/src/backend/executor/nodeIndexonlyscan.c
+++ b/src/backend/executor/nodeIndexonlyscan.c
@@ -604,7 +604,8 @@ ExecInitIndexOnlyScan(IndexOnlyScan *node, EState *estate, int eflags)
 /* ----------------------------------------------------------------
  *		ExecIndexOnlyScanEstimate
  *
- *	estimates the space required to serialize index-only scan node.
+ *		Compute the amount of space we'll need in the parallel
+ *		query DSM, and inform pcxt->estimator about our needs.
  * ----------------------------------------------------------------
  */
 void
diff --git a/src/backend/executor/nodeIndexscan.c b/src/backend/executor/nodeIndexscan.c
index 638b17b07c..262008240d 100644
--- a/src/backend/executor/nodeIndexscan.c
+++ b/src/backend/executor/nodeIndexscan.c
@@ -1644,7 +1644,8 @@ ExecIndexBuildScanKeys(PlanState *planstate, Relation index,
 /* ----------------------------------------------------------------
  *		ExecIndexScanEstimate
  *
- *		estimates the space required to serialize indexscan node.
+ *		Compute the amount of space we'll need in the parallel
+ *		query DSM, and inform pcxt->estimator about our needs.
  * ----------------------------------------------------------------
  */
 void
diff --git a/src/backend/executor/nodeSeqscan.c b/src/backend/executor/nodeSeqscan.c
index d4ac939c9b..76bec780a8 100644
--- a/src/backend/executor/nodeSeqscan.c
+++ b/src/backend/executor/nodeSeqscan.c
@@ -289,7 +289,8 @@ ExecReScanSeqScan(SeqScanState *node)
 /* ----------------------------------------------------------------
  *		ExecSeqScanEstimate
  *
- *		estimates the space required to serialize seqscan node.
+ *		Compute the amount of space we'll need in the parallel
+ *		query DSM, and inform pcxt->estimator about our needs.
  * ----------------------------------------------------------------
  */
 void