diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index d4427917476..3d8333bb848 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -88,8 +88,6 @@ static bool GetTupleForTrigger(EState *estate,
 							   LockTupleMode lockmode,
 							   TupleTableSlot *oldslot,
 							   TupleTableSlot **newSlot);
-static HeapTuple MaterializeTupleForTrigger(TupleTableSlot *slot,
-											bool *shouldFree);
 static bool TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
 						   Trigger *trigger, TriggerEvent event,
 						   Bitmapset *modifiedCols,
@@ -2673,7 +2671,7 @@ ExecBRUpdateTriggers(EState *estate, EPQState *epqstate,
 				ExecCopySlot(newslot, epqslot_clean);
 		}
 
-		trigtuple = MaterializeTupleForTrigger(oldslot, &should_free_trig);
+		trigtuple = ExecFetchSlotHeapTuple(oldslot, true, &should_free_trig);
 	}
 	else
 	{
@@ -3042,40 +3040,6 @@ GetTupleForTrigger(EState *estate,
 	return true;
 }
 
-/*
- * Extract a HeapTuple that we can pass off to trigger functions.
- *
- * We must materialize the tuple and make sure it is not dependent on any
- * attrmissing data.  This is needed for the old row in BEFORE UPDATE
- * triggers, since they can choose to pass back this exact tuple as the update
- * result, causing the tuple to be inserted into an executor slot that lacks
- * the attrmissing data.
- *
- * Currently we don't seem to need to remove the attrmissing dependency in any
- * other cases, but keep this as a separate function to simplify fixing things
- * if that changes.
- */
-static HeapTuple
-MaterializeTupleForTrigger(TupleTableSlot *slot, bool *shouldFree)
-{
-	HeapTuple	tup;
-	TupleDesc	tupdesc = slot->tts_tupleDescriptor;
-
-	tup = ExecFetchSlotHeapTuple(slot, true, shouldFree);
-	if (HeapTupleHeaderGetNatts(tup->t_data) < tupdesc->natts &&
-		tupdesc->constr && tupdesc->constr->missing)
-	{
-		HeapTuple	newtup;
-
-		newtup = heap_expand_tuple(tup, tupdesc);
-		if (*shouldFree)
-			heap_freetuple(tup);
-		*shouldFree = true;
-		tup = newtup;
-	}
-	return tup;
-}
-
 /*
  * Is trigger enabled to fire?
  */
diff --git a/src/backend/executor/execJunk.c b/src/backend/executor/execJunk.c
index 40d700dd9e2..1a822ff24b3 100644
--- a/src/backend/executor/execJunk.c
+++ b/src/backend/executor/execJunk.c
@@ -54,23 +54,48 @@
  *
  * The source targetlist is passed in.  The output tuple descriptor is
  * built from the non-junk tlist entries.
- * An optional resultSlot can be passed as well.
+ * An optional resultSlot can be passed as well; otherwise, we create one.
  */
 JunkFilter *
 ExecInitJunkFilter(List *targetList, TupleTableSlot *slot)
 {
-	JunkFilter *junkfilter;
 	TupleDesc	cleanTupType;
-	int			cleanLength;
-	AttrNumber *cleanMap;
-	ListCell   *t;
-	AttrNumber	cleanResno;
 
 	/*
 	 * Compute the tuple descriptor for the cleaned tuple.
 	 */
 	cleanTupType = ExecCleanTypeFromTL(targetList);
 
+	/*
+	 * The rest is the same as ExecInitJunkFilterInsertion, ie, we want to map
+	 * every non-junk targetlist column into the output tuple.
+	 */
+	return ExecInitJunkFilterInsertion(targetList, cleanTupType, slot);
+}
+
+/*
+ * ExecInitJunkFilterInsertion
+ *
+ * Initialize a JunkFilter for insertions into a table.
+ *
+ * Here, we are given the target "clean" tuple descriptor rather than
+ * inferring it from the targetlist.  Although the target descriptor can
+ * contain deleted columns, that is not of concern here, since the targetlist
+ * should contain corresponding NULL constants (cf. ExecCheckPlanOutput).
+ * It is assumed that the caller has checked that the table's columns match up
+ * with the non-junk columns of the targetlist.
+ */
+JunkFilter *
+ExecInitJunkFilterInsertion(List *targetList,
+							TupleDesc cleanTupType,
+							TupleTableSlot *slot)
+{
+	JunkFilter *junkfilter;
+	int			cleanLength;
+	AttrNumber *cleanMap;
+	ListCell   *t;
+	AttrNumber	cleanResno;
+
 	/*
 	 * Use the given slot, or make a new slot if we weren't given one.
 	 */
@@ -93,17 +118,18 @@ ExecInitJunkFilter(List *targetList, TupleTableSlot *slot)
 	if (cleanLength > 0)
 	{
 		cleanMap = (AttrNumber *) palloc(cleanLength * sizeof(AttrNumber));
-		cleanResno = 1;
+		cleanResno = 0;
 		foreach(t, targetList)
 		{
 			TargetEntry *tle = lfirst(t);
 
 			if (!tle->resjunk)
 			{
-				cleanMap[cleanResno - 1] = tle->resno;
+				cleanMap[cleanResno] = tle->resno;
 				cleanResno++;
 			}
 		}
+		Assert(cleanResno == cleanLength);
 	}
 	else
 		cleanMap = NULL;
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 20a4c474cc4..f450e4d80ad 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2681,15 +2681,27 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 				TupleTableSlot *junkresslot;
 
 				subplan = mtstate->mt_plans[i]->plan;
-				if (operation == CMD_INSERT || operation == CMD_UPDATE)
-					ExecCheckPlanOutput(resultRelInfo->ri_RelationDesc,
-										subplan->targetlist);
 
 				junkresslot =
 					ExecInitExtraTupleSlot(estate, NULL,
 										   table_slot_callbacks(resultRelInfo->ri_RelationDesc));
-				j = ExecInitJunkFilter(subplan->targetlist,
-									   junkresslot);
+
+				/*
+				 * For an INSERT or UPDATE, the result tuple must always match
+				 * the target table's descriptor.  For a DELETE, it won't
+				 * (indeed, there's probably no non-junk output columns).
+				 */
+				if (operation == CMD_INSERT || operation == CMD_UPDATE)
+				{
+					ExecCheckPlanOutput(resultRelInfo->ri_RelationDesc,
+										subplan->targetlist);
+					j = ExecInitJunkFilterInsertion(subplan->targetlist,
+													RelationGetDescr(resultRelInfo->ri_RelationDesc),
+													junkresslot);
+				}
+				else
+					j = ExecInitJunkFilter(subplan->targetlist,
+										   junkresslot);
 
 				if (operation == CMD_UPDATE || operation == CMD_DELETE)
 				{
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 415e117407c..238b77494f4 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -156,6 +156,9 @@ extern void ResetTupleHashTable(TupleHashTable hashtable);
  */
 extern JunkFilter *ExecInitJunkFilter(List *targetList,
 									  TupleTableSlot *slot);
+extern JunkFilter *ExecInitJunkFilterInsertion(List *targetList,
+											   TupleDesc cleanTupType,
+											   TupleTableSlot *slot);
 extern JunkFilter *ExecInitJunkFilterConversion(List *targetList,
 												TupleDesc cleanTupType,
 												TupleTableSlot *slot);
diff --git a/src/test/regress/expected/triggers.out b/src/test/regress/expected/triggers.out
index c19aac96742..f6610b0585b 100644
--- a/src/test/regress/expected/triggers.out
+++ b/src/test/regress/expected/triggers.out
@@ -216,34 +216,56 @@ select * from trigtest;
 
 drop table trigtest;
 -- Check behavior with an implicit column default, too (bug #16644)
-create table trigtest (a integer);
+create table trigtest (
+  a integer,
+  b bool default true not null,
+  c text default 'xyzzy' not null);
 create trigger trigger_return_old
 	before insert or delete or update on trigtest
 	for each row execute procedure trigger_return_old();
 insert into trigtest values(1);
 select * from trigtest;
- a 
----
- 1
+ a | b |   c   
+---+---+-------
+ 1 | t | xyzzy
 (1 row)
 
-alter table trigtest add column b integer default 42 not null;
+alter table trigtest add column d integer default 42 not null;
 select * from trigtest;
- a | b  
----+----
- 1 | 42
+ a | b |   c   | d  
+---+---+-------+----
+ 1 | t | xyzzy | 42
 (1 row)
 
 update trigtest set a = 2 where a = 1 returning *;
- a | b  
----+----
- 1 | 42
+ a | b |   c   | d  
+---+---+-------+----
+ 1 | t | xyzzy | 42
 (1 row)
 
 select * from trigtest;
- a | b  
----+----
- 1 | 42
+ a | b |   c   | d  
+---+---+-------+----
+ 1 | t | xyzzy | 42
+(1 row)
+
+alter table trigtest drop column b;
+select * from trigtest;
+ a |   c   | d  
+---+-------+----
+ 1 | xyzzy | 42
+(1 row)
+
+update trigtest set a = 2 where a = 1 returning *;
+ a |   c   | d  
+---+-------+----
+ 1 | xyzzy | 42
+(1 row)
+
+select * from trigtest;
+ a |   c   | d  
+---+-------+----
+ 1 | xyzzy | 42
 (1 row)
 
 drop table trigtest;
diff --git a/src/test/regress/sql/triggers.sql b/src/test/regress/sql/triggers.sql
index bf2e73abf60..9c3872eb145 100644
--- a/src/test/regress/sql/triggers.sql
+++ b/src/test/regress/sql/triggers.sql
@@ -155,7 +155,10 @@ select * from trigtest;
 drop table trigtest;
 
 -- Check behavior with an implicit column default, too (bug #16644)
-create table trigtest (a integer);
+create table trigtest (
+  a integer,
+  b bool default true not null,
+  c text default 'xyzzy' not null);
 
 create trigger trigger_return_old
 	before insert or delete or update on trigtest
@@ -164,7 +167,13 @@ create trigger trigger_return_old
 insert into trigtest values(1);
 select * from trigtest;
 
-alter table trigtest add column b integer default 42 not null;
+alter table trigtest add column d integer default 42 not null;
+
+select * from trigtest;
+update trigtest set a = 2 where a = 1 returning *;
+select * from trigtest;
+
+alter table trigtest drop column b;
 
 select * from trigtest;
 update trigtest set a = 2 where a = 1 returning *;