Fix assertions with RI triggers in heap_update and heap_delete.

hlinnaka · hlinnaka · commit b8a606e21b06 · 2023-11-28T11:59:53.000+02:00
If the tuple being updated is not visible to the crosscheck snapshot, we return TM_Updated but the assertions would not hold in that case. Move them to before the cross-check. Fixes bug #17893. Backpatch to all supported versions. Author: Alexander Lakhin Backpatch-through: 12 Discussion: https://www.postgresql.org/message-id/17893-35847009eec517b5%40postgresql.org
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
@@ -2677,13 +2677,7 @@ heap_delete(Relation relation, ItemPointer tid,
 			result = TM_Deleted;
 	}
 
-	if (crosscheck != InvalidSnapshot && result == TM_Ok)
-	{
-		/* Perform additional check for transaction-snapshot mode RI updates */
-		if (!HeapTupleSatisfiesVisibility(&tp, crosscheck, buffer))
-			result = TM_Updated;
-	}
-
+	/* sanity check the result HeapTupleSatisfiesUpdate() and the logic above */
 	if (result != TM_Ok)
 	{
 		Assert(result == TM_SelfModified ||
@@ -2693,6 +2687,17 @@ heap_delete(Relation relation, ItemPointer tid,
 		Assert(!(tp.t_data->t_infomask & HEAP_XMAX_INVALID));
 		Assert(result != TM_Updated ||
 			   !ItemPointerEquals(&tp.t_self, &tp.t_data->t_ctid));
+	}
+
+	if (crosscheck != InvalidSnapshot && result == TM_Ok)
+	{
+		/* Perform additional check for transaction-snapshot mode RI updates */
+		if (!HeapTupleSatisfiesVisibility(&tp, crosscheck, buffer))
+			result = TM_Updated;
+	}
+
+	if (result != TM_Ok)
+	{
 		tmfd->ctid = tp.t_data->t_ctid;
 		tmfd->xmax = HeapTupleHeaderGetUpdateXid(tp.t_data);
 		if (result == TM_SelfModified)
@@ -3320,16 +3325,7 @@ heap_update(Relation relation, ItemPointer otid, HeapTuple newtup,
 			result = TM_Deleted;
 	}
 
-	if (crosscheck != InvalidSnapshot && result == TM_Ok)
-	{
-		/* Perform additional check for transaction-snapshot mode RI updates */
-		if (!HeapTupleSatisfiesVisibility(&oldtup, crosscheck, buffer))
-		{
-			result = TM_Updated;
-			Assert(!ItemPointerEquals(&oldtup.t_self, &oldtup.t_data->t_ctid));
-		}
-	}
-
+	/* Sanity check the result HeapTupleSatisfiesUpdate() and the logic above */
 	if (result != TM_Ok)
 	{
 		Assert(result == TM_SelfModified ||
@@ -3339,6 +3335,17 @@ heap_update(Relation relation, ItemPointer otid, HeapTuple newtup,
 		Assert(!(oldtup.t_data->t_infomask & HEAP_XMAX_INVALID));
 		Assert(result != TM_Updated ||
 			   !ItemPointerEquals(&oldtup.t_self, &oldtup.t_data->t_ctid));
+	}
+
+	if (crosscheck != InvalidSnapshot && result == TM_Ok)
+	{
+		/* Perform additional check for transaction-snapshot mode RI updates */
+		if (!HeapTupleSatisfiesVisibility(&oldtup, crosscheck, buffer))
+			result = TM_Updated;
+	}
+
+	if (result != TM_Ok)
+	{
 		tmfd->ctid = oldtup.t_data->t_ctid;
 		tmfd->xmax = HeapTupleHeaderGetUpdateXid(oldtup.t_data);
 		if (result == TM_SelfModified)
diff --git a/src/include/access/tableam.h b/src/include/access/tableam.h
@@ -1220,8 +1220,8 @@ table_multi_insert(Relation rel, TupleTableSlot **slots, int nslots,
  * TM_BeingModified (the last only possible if wait == false).
  *
  * In the failure cases, the routine fills *tmfd with the tuple's t_ctid,
- * t_xmax, and, if possible, and, if possible, t_cmax.  See comments for
- * struct TM_FailureData for additional info.
+ * t_xmax, and, if possible, t_cmax.  See comments for struct
+ * TM_FailureData for additional info.
  */
 static inline TM_Result
 table_tuple_delete(Relation rel, ItemPointer tid, CommandId cid,
