Function ExecParallelScanHashBucket

src/backend/executor/nodeHash.c:2319–2369

* ExecParallelScanHashBucket * scan a hash bucket for matches to the current outer tuple * * The current outer tuple must be stored in econtext->ecxt_outertuple. * * On success, the inner tuple is stored into hjstate->hj_CurTuple and * econtext->ecxt_innertuple, using hjstate->hj_HashTupleSlot as the slot * for the latter. */

 * for the latter.
 */
bool
ExecParallelScanHashBucket(HashState *hashState, HashJoinState *hjstate,
						   ExprContext *econtext)
{
	/*
	 * Greenplum specific behavior.
	 * Using hashqualclauses to support hash join on 'IS NOT DISTINCT FROM'
	 * as well as '='.
	 */
	ExprState  *hjclauses = hjstate->hashqualclauses;
	HashJoinTable hashtable = hjstate->hj_HashTable;
	HashJoinTuple hashTuple = hjstate->hj_CurTuple;
	uint32		hashvalue = hjstate->hj_CurHashValue;

	/*
	 * hj_CurTuple is the address of the tuple last returned from the current
	 * bucket, or NULL if it's time to start scanning a new bucket.
	 */
	if (hashTuple != NULL)
		hashTuple = ExecParallelHashNextTuple(hashtable, hashTuple);
	else
		hashTuple = ExecParallelHashFirstTuple(hashtable,
											   hjstate->hj_CurBucketNo);

	while (hashTuple != NULL)
	{
		if (hashTuple->hashvalue == hashvalue)
		{
			TupleTableSlot *inntuple;

			/* insert hashtable's tuple into exec slot so ExecQual sees it */
			inntuple = ExecStoreMinimalTuple(HJTUPLE_MINTUPLE(hashTuple),
											 hjstate->hj_HashTupleSlot,
											 false);	/* do not pfree */
			econtext->ecxt_innertuple = inntuple;

			if (ExecQualAndReset(hjclauses, econtext))
			{
				hjstate->hj_CurTuple = hashTuple;
				return true;
			}
		}

		hashTuple = ExecParallelHashNextTuple(hashtable, hashTuple);
	}

	/*
	 * no match
	 */
	return false;
}

/*
 * ExecPrepHashTableForUnmatched