added try--finally

			$query->andWhere($query->expr()->in('a.uid', $placeholders));

		}

		$result = $query->execute();

		$result = null;

		$users = [];

		try {

			$result = $query->execute();

			while ($row = $result->fetch()) {

				$users[] = $row['uid'];

			}

		} finally {

			if ($result !== null) {

				$result->closeCursor();

			}

		}

		return $users;

	}