1 files changed, 40 insertions, 1 deletions

diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 28b98d10ae8..59289f8d4d3 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -89,6 +89,8 @@ 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,
@@ -2672,7 +2674,7 @@ ExecBRUpdateTriggers(EState *estate, EPQState *epqstate,
 				ExecCopySlot(newslot, epqslot_clean);
 		}
 
-		trigtuple = ExecFetchSlotHeapTuple(oldslot, true, &should_free_trig);
+		trigtuple = MaterializeTupleForTrigger(oldslot, &should_free_trig);
 	}
 	else
 	{
@@ -2925,6 +2927,9 @@ ExecASTruncateTriggers(EState *estate, ResultRelInfo *relinfo)
 }
 
 
+/*
+ * Fetch tuple into "oldslot", dealing with locking and EPQ if necessary
+ */
 static bool
 GetTupleForTrigger(EState *estate,
 				   EPQState *epqstate,
@@ -3039,6 +3044,40 @@ GetTupleForTrigger(EState *estate,
 }
 
 /*
+ * 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?
  */
 static bool