Forecasting in Online Caching

Abstract

This paper explores the effect of forecasting methods on the Optimistic Follow The Regularized Leader (OFTRL) caching policy. It has been theoretically proven that the performance of OFTRL improves with accurate forecasters. However, the forecasters were portrayed as black boxes. In this paper, we do not treat forecasters as a black box but rather use recommender systems and temporal convolutional networks (TCN) implementations as forecasters for OFTRL in the caching context. The said forecasters predict the next file requests directly from the request trace rather than monitoring popularity. Using request traces extracted from the well-known MovieLens dataset, it was found that incorporating a forecaster into an optimistic learning algorithm is not straightforward. In fact, it was found that simpler approaches such as one that predicts the most requested file, can outperform more complicated deep learning models in terms of regret even if they possess a lower accuracy.