	public function addGroupBy( $groupBy ) {
		if ( empty( $groupBy ) ) {
			throw new \MWException( __METHOD__ . ': An empty group by clause was passed.' );
		}
		$this->groupBy[] = $groupBy;
		return true;
	}
The software does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.