Cache-Aware Reinforcement Learning in Large-Scale Recommender Systems

Fuente: arXiv
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Autori principali: Chen, Xiaoshuang, Zhang, Gengrui, Wang, Yao, Wu, Yulin, Su, Shuo, Zhan, Kaiqiao, Wang, Ben
Natura: Preprint
Pubblicazione: 2024
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author Chen, Xiaoshuang
Zhang, Gengrui
Wang, Yao
Wu, Yulin
Su, Shuo
Zhan, Kaiqiao
Wang, Ben
author_facet Chen, Xiaoshuang
Zhang, Gengrui
Wang, Yao
Wu, Yulin
Su, Shuo
Zhan, Kaiqiao
Wang, Ben
contents Modern large-scale recommender systems are built upon computation-intensive infrastructure and usually suffer from a huge difference in traffic between peak and off-peak periods. In peak periods, it is challenging to perform real-time computation for each request due to the limited budget of computational resources. The recommendation with a cache is a solution to this problem, where a user-wise result cache is used to provide recommendations when the recommender system cannot afford a real-time computation. However, the cached recommendations are usually suboptimal compared to real-time computation, and it is challenging to determine the items in the cache for each user. In this paper, we provide a cache-aware reinforcement learning (CARL) method to jointly optimize the recommendation by real-time computation and by the cache. We formulate the problem as a Markov decision process with user states and a cache state, where the cache state represents whether the recommender system performs recommendations by real-time computation or by the cache. The computational load of the recommender system determines the cache state. We perform reinforcement learning based on such a model to improve user engagement over multiple requests. Moreover, we show that the cache will introduce a challenge called critic dependency, which deteriorates the performance of reinforcement learning. To tackle this challenge, we propose an eigenfunction learning (EL) method to learn independent critics for CARL. Experiments show that CARL can significantly improve the users' engagement when considering the result cache. CARL has been fully launched in Kwai app, serving over 100 million users.
format Preprint
id arxiv_https___arxiv_org_abs_2404_14961
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Cache-Aware Reinforcement Learning in Large-Scale Recommender Systems
Chen, Xiaoshuang
Zhang, Gengrui
Wang, Yao
Wu, Yulin
Su, Shuo
Zhan, Kaiqiao
Wang, Ben
Machine Learning
Information Retrieval
Modern large-scale recommender systems are built upon computation-intensive infrastructure and usually suffer from a huge difference in traffic between peak and off-peak periods. In peak periods, it is challenging to perform real-time computation for each request due to the limited budget of computational resources. The recommendation with a cache is a solution to this problem, where a user-wise result cache is used to provide recommendations when the recommender system cannot afford a real-time computation. However, the cached recommendations are usually suboptimal compared to real-time computation, and it is challenging to determine the items in the cache for each user. In this paper, we provide a cache-aware reinforcement learning (CARL) method to jointly optimize the recommendation by real-time computation and by the cache. We formulate the problem as a Markov decision process with user states and a cache state, where the cache state represents whether the recommender system performs recommendations by real-time computation or by the cache. The computational load of the recommender system determines the cache state. We perform reinforcement learning based on such a model to improve user engagement over multiple requests. Moreover, we show that the cache will introduce a challenge called critic dependency, which deteriorates the performance of reinforcement learning. To tackle this challenge, we propose an eigenfunction learning (EL) method to learn independent critics for CARL. Experiments show that CARL can significantly improve the users' engagement when considering the result cache. CARL has been fully launched in Kwai app, serving over 100 million users.
title Cache-Aware Reinforcement Learning in Large-Scale Recommender Systems
topic Machine Learning
Information Retrieval
url https://arxiv.org/abs/2404.14961