This paper studies learning-augmented and randomized online aggregation with delays on a line metric. We consider advice given as online suggested service lengths, and evaluate the algorithms in terms of robustness and consistency. For each
λ∈(0,1], we first propose a deterministic learning-augmented \textsc{Balance} algorithm that is
(4/λ+1/λ2)-robust and
(4+λ)-consistent. We also propose a randomized algorithm for the problem in the classical adversarial model, which is
(e+1)-competitive against an oblivious adversary, improving over the deterministic
5-competitive \textsc{Balance} benchmark~\cite{bienkowski2013chain}. Notably, this competitive ratio is even lower than the lower bound of
4 for deterministic online algorithms. Moreover, we establish a lower bound of
e on the competitive ratio of randomized online algorithms, improving the previous lower bound of
e/(e−1). Besides, we combine the two ideas and obtain a randomized learning-augmented algorithm that is
(e/λ+1/λ2)-robust and
(e+λ)-consistent. Finally, we conduct numerical experiments to complement our theoretical analysis and evaluate the empirical performance of our algorithms.