diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index af7b26c..f17bc6b 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -201,12 +201,19 @@ ExecCheckHeapTupleVisible(EState *estate,
 }
 
 /*
- * ExecCheckTIDVisible -- convenience variant of ExecCheckHeapTupleVisible()
+ * ExecCheckTIDVisibleOrSelfInserted -- fetch tuple and check visibility
+ *
+ * Runs ExecCheckHeapTupleVisible, unless the tuple was inserted by the
+ * current transaction.  The check for tuples inserted by the same transaction
+ * is redundant in the case of commands that insert a single tuple since the
+ * visibility check will be satisfied.  In the case of commands that insert
+ * multiple tuples, we don't want to report a serialization failure when we
+ * encounter tuples inserted earlier.
  */
 static void
-ExecCheckTIDVisible(EState *estate,
-					ResultRelInfo *relinfo,
-					ItemPointer tid)
+ExecCheckTIDVisibleOrSelfInserted(EState *estate,
+								  ResultRelInfo *relinfo,
+								  ItemPointer tid)
 {
 	Relation	rel = relinfo->ri_RelationDesc;
 	Buffer		buffer;
@@ -219,7 +226,8 @@ ExecCheckTIDVisible(EState *estate,
 	tuple.t_self = *tid;
 	if (!heap_fetch(rel, SnapshotAny, &tuple, &buffer, false, NULL))
 		elog(ERROR, "failed to fetch conflicting tuple for ON CONFLICT");
-	ExecCheckHeapTupleVisible(estate, &tuple, buffer);
+	if (!TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmin(tuple.t_data)))
+		ExecCheckHeapTupleVisible(estate, &tuple, buffer);
 	ReleaseBuffer(buffer);
 }
 
@@ -410,7 +418,8 @@ ExecInsert(ModifyTableState *mtstate,
 					 * snapshot at higher isolation levels.
 					 */
 					Assert(onconflict == ONCONFLICT_NOTHING);
-					ExecCheckTIDVisible(estate, resultRelInfo, &conflictTid);
+					ExecCheckTIDVisibleOrSelfInserted(estate, resultRelInfo,
+													  &conflictTid);
 					InstrCountFiltered2(&mtstate->ps, 1);
 					return NULL;
 				}