Function ExecParallelHashJoinOuterGetTuple

src/backend/executor/nodeHashjoin.c:1180–1245

* ExecHashJoinOuterGetTuple variant for the parallel case. */

 * ExecHashJoinOuterGetTuple variant for the parallel case.
 */
static TupleTableSlot *
ExecParallelHashJoinOuterGetTuple(PlanState *outerNode,
								  HashJoinState *hjstate,
								  uint32 *hashvalue)
{
	HashJoinTable hashtable = hjstate->hj_HashTable;
	int			curbatch = hashtable->curbatch;
	TupleTableSlot *slot;
	HashState  *hashState = (HashState *) innerPlanState(hjstate);

	/*
	 * In the Parallel Hash case we only run the outer plan directly for
	 * single-batch hash joins.  Otherwise we have to go to batch files, even
	 * for batch 0.
	 */
	if (curbatch == 0 && hashtable->nbatch == 1)
	{
		slot = ExecProcNode(outerNode);

		while (!TupIsNull(slot))
		{
			ExprContext *econtext = hjstate->js.ps.ps_ExprContext;
			bool		hashkeys_null = false;
			bool		keep_nulls;

			keep_nulls = HJ_FILL_OUTER(hjstate) ||
				hjstate->hj_nonequijoin;

			econtext->ecxt_outertuple = slot;
			if (ExecHashGetHashValue(hashState,
									 hashtable, econtext,
									 hjstate->hj_OuterHashKeys,
									 true,	/* outer tuple */
									 keep_nulls,
									 hashvalue,
									 &hashkeys_null))
				return slot;

			/*
			 * That tuple couldn't match because of a NULL, so discard it and
			 * continue with the next one.
			 */
			slot = ExecProcNode(outerNode);
		}
	}
	else if (curbatch < hashtable->nbatch)
	{
		MinimalTuple tuple;

		tuple = sts_parallel_scan_next(hashtable->batches[curbatch].outer_tuples,
									   hashvalue);
		if (tuple != NULL)
		{
			ExecForceStoreMinimalTuple(tuple,
									   hjstate->hj_OuterTupleSlot,
									   false);
			slot = hjstate->hj_OuterTupleSlot;
			return slot;