Function AggregateConsume

src/execution_plan/ops/op_aggregate.c:267–322

}

static Record AggregateConsume
(
	OpBase *opBase
) {
	OpAggregate *op = (OpAggregate *)opBase;
	if(op->group_iter != NULL) {
		return _handoff(op);
	}

	Record r;
	if(op->op.childCount == 0) {
		// RETURN max (1)
		// create a 'fake' record
		r = OpBase_CreateRecord(opBase);
		_aggregateRecord(op, r);
	} else {
		OpBase *child = op->op.children[0];
		// eager consumption!
		while((r = OpBase_Consume(child))) {
			_aggregateRecord(op, r);
		}
	}

	// did we process any records?
	// does aggregation contains keys?
	// e.g.
	// MATCH (n:N) WHERE n.noneExisting = 2 RETURN count(n)
	if(HashTableElemCount(op->groups) == 0 && op->key_count == 0) {

		// no data was processed and aggregation doesn't have a key
		// in this case we want to return aggregation default value
		// aggregate on an empty record
		ASSERT(op->op.childCount > 0);

		// use child record
		// this is required in case this aggregation is perford within the
		// context of a WITH projection as we need the child's mapping for
		// expression evaluation
		// there's no harm in doing so when not in a WITH aggregation,
		// as we'll be using the same mapping;
		// this operation and it child are in the same scope
		OpBase *child = op->op.children[0];
		r = OpBase_CreateRecord(child);

		// get group
		_GetGroup(op, r);

		// free record
		OpBase_DeleteRecord(r);
	}

	// create group iterator
	op->group_iter = HashTableGetIterator(op->groups);

	return _handoff(op);
}

static OpResult AggregateReset