diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 6d2624e75b8..15ef3304863 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -4524,6 +4524,7 @@ show_modifytable_info(ModifyTableState *mtstate, List *ancestors,
 	const char *operation;
 	const char *foperation;
 	bool		labeltargets;
+	bool		nopruning;
 	int			j;
 	List	   *idxNames = NIL;
 	ListCell   *lst;
@@ -4571,6 +4572,16 @@ show_modifytable_info(ModifyTableState *mtstate, List *ancestors,
 	if (labeltargets)
 		ExplainOpenGroup("Target Tables", "Target Tables", false, es);
 
+	/*
+	 * node->fdwPrivLists is parallel to node->resultRelations, in the
+	 * original pre-pruning order.  If no result relations were pruned, the
+	 * entries in mtstate->resultRelInfo[] are in that same order and can be
+	 * matched to fdwPrivLists positionally; otherwise we have to look each
+	 * one up by range table index below.  This test is loop-invariant, so
+	 * compute it once here.
+	 */
+	nopruning = (list_length(node->resultRelations) == mtstate->mt_nrels);
+
 	for (j = 0; j < mtstate->mt_nrels; j++)
 	{
 		ResultRelInfo *resultRelInfo = mtstate->resultRelInfo + j;
@@ -4609,7 +4620,30 @@ show_modifytable_info(ModifyTableState *mtstate, List *ancestors,
 			fdwroutine != NULL &&
 			fdwroutine->ExplainForeignModify != NULL)
 		{
-			List	   *fdw_private = (List *) list_nth(mtstate->mt_fdwPrivLists, j);
+			List	   *fdw_private;
+
+			/*
+			 * Find this relation's fdw_private: index fdwPrivLists directly
+			 * when nothing was pruned, else match by range table index.
+			 */
+			if (nopruning)
+				fdw_private = (List *) list_nth(node->fdwPrivLists, j);
+			else
+			{
+				Index		rti = resultRelInfo->ri_RangeTableIndex;
+				ListCell   *lc1;
+				ListCell   *lc2;
+
+				fdw_private = NIL;
+				forboth(lc1, node->resultRelations, lc2, node->fdwPrivLists)
+				{
+					if (lfirst_int(lc1) == (int) rti)
+					{
+						fdw_private = (List *) lfirst(lc2);
+						break;
+					}
+				}
+			}
 
 			fdwroutine->ExplainForeignModify(mtstate,
 											 resultRelInfo,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index cac30666663..7c1d0e9588e 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -4770,7 +4770,6 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 	mtstate->mt_updateColnosLists = updateColnosLists;
 	mtstate->mt_mergeActionLists = mergeActionLists;
 	mtstate->mt_mergeJoinConditions = mergeJoinConditions;
-	mtstate->mt_fdwPrivLists = fdwPrivLists;
 
 	/*----------
 	 * Resolve the target relation. This is the same as:
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 6677a03caab..409e172bfb6 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1453,15 +1453,13 @@ typedef struct ModifyTableState
 	double		mt_merge_deleted;
 
 	/*
-	 * Lists of valid updateColnosLists, mergeActionLists,
-	 * mergeJoinConditions, and fdwPrivLists.  These contain only entries for
-	 * unpruned relations, filtered from the corresponding lists in
-	 * ModifyTable.
+	 * Lists of valid updateColnosLists, mergeActionLists, and
+	 * mergeJoinConditions.  These contain only entries for unpruned
+	 * relations, filtered from the corresponding lists in ModifyTable.
 	 */
 	List	   *mt_updateColnosLists;
 	List	   *mt_mergeActionLists;
 	List	   *mt_mergeJoinConditions;
-	List	   *mt_fdwPrivLists;
 } ModifyTableState;
 
 /* ----------------