diff --git a/contrib/pg_overexplain/expected/pg_overexplain.out b/contrib/pg_overexplain/expected/pg_overexplain.out
index f4ce828bc62..198bbe10d73 100644
--- a/contrib/pg_overexplain/expected/pg_overexplain.out
+++ b/contrib/pg_overexplain/expected/pg_overexplain.out
@@ -452,6 +452,8 @@ SELECT * FROM vegetables WHERE genus = 'daucus';
  Seq Scan on daucus vegetables
    Filter: (genus = 'daucus'::text)
    Scan RTI: 2
+   Elided Node Type: Append
+   Elided Node RTIs: 1
  RTI 1 (relation, inherited, in-from-clause):
    Eref: vegetables (id, name, genus)
    Relation: vegetables
@@ -465,7 +467,7 @@ SELECT * FROM vegetables WHERE genus = 'daucus';
    Relation Kind: relation
    Relation Lock Mode: AccessShareLock
  Unprunable RTIs: 1 2
-(16 rows)
+(18 rows)
 
 -- Also test a case that involves a write.
 EXPLAIN (RANGE_TABLE, COSTS OFF)
@@ -499,6 +501,10 @@ SELECT * FROM vegetables v,
    ->  Seq Scan on daucus vegetables
          Filter: (genus = 'daucus'::text)
          Scan RTI: 6
+         Elided Node Type: Append
+         Elided Node RTIs: 5
+         Elided Node Type: SubqueryScan
+         Elided Node RTIs: 2
    ->  Append
          Append RTIs: 1
          ->  Seq Scan on brassica v_1
@@ -542,7 +548,7 @@ SELECT * FROM vegetables v,
    Relation Kind: relation
    Relation Lock Mode: AccessShareLock
  Unprunable RTIs: 1 3 4 5 6
-(47 rows)
+(51 rows)
 
 -- should show "Subplan: unnamed_subquery"
 EXPLAIN (RANGE_TABLE, COSTS OFF)
@@ -554,6 +560,10 @@ SELECT * FROM vegetables v,
    ->  Seq Scan on daucus vegetables
          Filter: (genus = 'daucus'::text)
          Scan RTI: 6
+         Elided Node Type: Append
+         Elided Node RTIs: 5
+         Elided Node Type: SubqueryScan
+         Elided Node RTIs: 2
    ->  Append
          Append RTIs: 1
          ->  Seq Scan on brassica v_1
@@ -596,5 +606,5 @@ SELECT * FROM vegetables v,
    Relation Kind: relation
    Relation Lock Mode: AccessShareLock
  Unprunable RTIs: 1 3 4 5 6
-(46 rows)
+(50 rows)
 
diff --git a/contrib/pg_overexplain/pg_overexplain.c b/contrib/pg_overexplain/pg_overexplain.c
index bf8c768ed47..e0184ba314a 100644
--- a/contrib/pg_overexplain/pg_overexplain.c
+++ b/contrib/pg_overexplain/pg_overexplain.c
@@ -191,6 +191,8 @@ overexplain_per_node_hook(PlanState *planstate, List *ancestors,
 	 */
 	if (options->range_table)
 	{
+		bool		opened_elided_nodes = false;
+
 		switch (nodeTag(plan))
 		{
 			case T_SeqScan:
@@ -251,6 +253,43 @@ overexplain_per_node_hook(PlanState *planstate, List *ancestors,
 			default:
 				break;
 		}
+
+		foreach_node(ElidedNode, n, es->pstmt->elidedNodes)
+		{
+			char	   *elidednodetag;
+
+			if (n->plan_node_id != plan->plan_node_id)
+				continue;
+
+			if (!opened_elided_nodes)
+			{
+				ExplainOpenGroup("Elided Nodes", "Elided Nodes", false, es);
+				opened_elided_nodes = true;
+			}
+
+			switch (n->elided_type)
+			{
+				case T_Append:
+					elidednodetag = "Append";
+					break;
+				case T_MergeAppend:
+					elidednodetag = "MergeAppend";
+					break;
+				case T_SubqueryScan:
+					elidednodetag = "SubqueryScan";
+					break;
+				default:
+					elidednodetag = psprintf("%d", n->elided_type);
+					break;
+			}
+
+			ExplainOpenGroup("Elided Node", NULL, true, es);
+			ExplainPropertyText("Elided Node Type", elidednodetag, es);
+			overexplain_bitmapset("Elided Node RTIs", n->relids, es);
+			ExplainCloseGroup("Elided Node", NULL, true, es);
+		}
+		if (opened_elided_nodes)
+			ExplainCloseGroup("Elided Nodes", "Elided Nodes", false, es);
 	}
 }
 
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 2c9fb50b610..f68142cfcb8 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -666,6 +666,7 @@ standard_planner(Query *parse, const char *query_string, int cursorOptions,
 	result->paramExecTypes = glob->paramExecTypes;
 	/* utilityStmt should be null, but we might as well copy it */
 	result->utilityStmt = parse->utilityStmt;
+	result->elidedNodes = glob->elidedNodes;
 	result->stmt_location = parse->stmt_location;
 	result->stmt_len = parse->stmt_len;
 
diff --git a/src/backend/optimizer/plan/setrefs.c b/src/backend/optimizer/plan/setrefs.c
index a5b2314ef2a..5ad6c13830b 100644
--- a/src/backend/optimizer/plan/setrefs.c
+++ b/src/backend/optimizer/plan/setrefs.c
@@ -211,6 +211,9 @@ static List *set_windowagg_runcondition_references(PlannerInfo *root,
 												   List *runcondition,
 												   Plan *plan);
 
+static void record_elided_node(PlannerGlobal *glob, int plan_node_id,
+							   NodeTag elided_type, Bitmapset *relids);
+
 
 /*****************************************************************************
  *
@@ -1460,10 +1463,17 @@ set_subqueryscan_references(PlannerInfo *root,
 
 	if (trivial_subqueryscan(plan))
 	{
+		Index		scanrelid;
+
 		/*
 		 * We can omit the SubqueryScan node and just pull up the subplan.
 		 */
 		result = clean_up_removed_plan_level((Plan *) plan, plan->subplan);
+
+		/* Remember that we removed a SubqueryScan */
+		scanrelid = plan->scan.scanrelid + rtoffset;
+		record_elided_node(root->glob, plan->subplan->plan_node_id,
+						   T_SubqueryScan, bms_make_singleton(scanrelid));
 	}
 	else
 	{
@@ -1891,7 +1901,17 @@ set_append_references(PlannerInfo *root,
 		Plan	   *p = (Plan *) linitial(aplan->appendplans);
 
 		if (p->parallel_aware == aplan->plan.parallel_aware)
-			return clean_up_removed_plan_level((Plan *) aplan, p);
+		{
+			Plan	   *result;
+
+			result = clean_up_removed_plan_level((Plan *) aplan, p);
+
+			/* Remember that we removed an Append */
+			record_elided_node(root->glob, p->plan_node_id, T_Append,
+							   offset_relid_set(aplan->apprelids, rtoffset));
+
+			return result;
+		}
 	}
 
 	/*
@@ -1959,7 +1979,17 @@ set_mergeappend_references(PlannerInfo *root,
 		Plan	   *p = (Plan *) linitial(mplan->mergeplans);
 
 		if (p->parallel_aware == mplan->plan.parallel_aware)
-			return clean_up_removed_plan_level((Plan *) mplan, p);
+		{
+			Plan	   *result;
+
+			result = clean_up_removed_plan_level((Plan *) mplan, p);
+
+			/* Remember that we removed a MergeAppend */
+			record_elided_node(root->glob, p->plan_node_id, T_MergeAppend,
+							   offset_relid_set(mplan->apprelids, rtoffset));
+
+			return result;
+		}
 	}
 
 	/*
@@ -3774,3 +3804,21 @@ extract_query_dependencies_walker(Node *node, PlannerInfo *context)
 	return expression_tree_walker(node, extract_query_dependencies_walker,
 								  context);
 }
+
+/*
+ * Record some details about a node removed from the plan during setrefs
+ * processing, for the benefit of code trying to reconstruct planner decisions
+ * from examination of the final plan tree.
+ */
+static void
+record_elided_node(PlannerGlobal *glob, int plan_node_id,
+				   NodeTag elided_type, Bitmapset *relids)
+{
+	ElidedNode *n = makeNode(ElidedNode);
+
+	n->plan_node_id = plan_node_id;
+	n->elided_type = elided_type;
+	n->relids = relids;
+
+	glob->elidedNodes = lappend(glob->elidedNodes, n);
+}
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index c1e9397623b..9cc5d2e7411 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -232,6 +232,9 @@ typedef struct PlannerGlobal
 	/* type OIDs for PARAM_EXEC Params */
 	List	   *paramExecTypes;
 
+	/* info about nodes elided from the plan during setrefs processing */
+	List	   *elidedNodes;
+
 	/* highest PlaceHolderVar ID assigned */
 	Index		lastPHId;
 
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index 9ae72a607e2..0ad0ff404c9 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -152,6 +152,9 @@ typedef struct PlannedStmt
 	/* non-null if this is utility stmt */
 	Node	   *utilityStmt;
 
+	/* info about nodes elided from the plan during setrefs processing */
+	List	   *elidedNodes;
+
 	/*
 	 * DefElem objects added by extensions, e.g. using planner_shutdown_hook
 	 *
@@ -1838,4 +1841,21 @@ typedef struct SubPlanRTInfo
 	bool		dummy;
 } SubPlanRTInfo;
 
+/*
+ * ElidedNode
+ *
+ * Information about nodes elided from the final plan tree: trivial subquery
+ * scans, and single-child Append and MergeAppend nodes.
+ *
+ * plan_node_id is that of the surviving plan node, the sole child of the
+ * one which was elided.
+ */
+typedef struct ElidedNode
+{
+	NodeTag		type;
+	int			plan_node_id;
+	NodeTag		elided_type;
+	Bitmapset  *relids;
+} ElidedNode;
+
 #endif							/* PLANNODES_H */
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index e83ced4d746..523977721ea 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -710,6 +710,7 @@ EachState
 Edge
 EditableObjectType
 ElementsState
+ElidedNode
 EnableTimeoutParams
 EndDataPtrType
 EndDirectModify_function