Function ExecStoreAllNullTuple

src/backend/executor/execTuples.c:1592–1613

-------------------------------- * ExecStoreAllNullTuple * Set up the slot to contain a null in every column. * * At first glance this might sound just like ExecClearTuple, but it's * entirely different: the slot ends up full, not empty. * -------------------------------- */

 * --------------------------------
 */
TupleTableSlot *
ExecStoreAllNullTuple(TupleTableSlot *slot)
{
	/*
	 * sanity checks
	 */
	Assert(slot != NULL);
	Assert(slot->tts_tupleDescriptor != NULL);

	/* Clear any old contents */
	ExecClearTuple(slot);

	/*
	 * Fill all the columns of the virtual tuple with nulls
	 */
	MemSet(slot->tts_values, 0,
		   slot->tts_tupleDescriptor->natts * sizeof(Datum));
	memset(slot->tts_isnull, true,
		   slot->tts_tupleDescriptor->natts * sizeof(bool));

	return ExecStoreVirtualTuple(slot);
}

/*
 * Store a HeapTuple in datum form, into a slot. That always requires