Hybrid-RACA: Hybrid Retrieval-Augmented Composition Assistance for Real-time Text Prediction
Menglin Xia, Xuchao Zhang, Camille Couturier, Guoqing Zheng, Saravan Rajmohan, Victor Ruhle
TL;DR
Hybrid-RACA addresses the latency-cost tension in retrieval-augmented text prediction by pairing a small on-device predictor with cloud-generated memory. It introduces an asynchronous memory-update mechanism driven by an augmentation coordinator and a cloud memory generator that compresses retrieved documents into concise takeaways, forming memory $m_t$ for real-time use. The client is instruction-tuned to leverage this memory, with a loss that aligns its outputs to LLM-generated targets, achieving strong utility on multiple datasets while keeping latency low. The approach demonstrates practical benefits for edge-based real-time composition and suggests broader applicability to hybrid edge-cloud AI systems.
Abstract
Large language models (LLMs) enhanced with retrieval augmentation has shown great performance in many applications. However, the computational demands for these models pose a challenge when applying them to real-time tasks, such as composition assistance. To address this, we propose Hybrid Retrieval-Augmented Composition Assistance (Hybrid-RACA), a novel system for real-time text prediction that efficiently combines a cloud-based LLM with a smaller client-side model through retrieval augmented memory. This integration enables the client model to generate better responses, benefiting from the LLM's capabilities and cloud-based data. Meanwhile, via a novel asynchronous memory update mechanism, the client model can deliver real-time completions to user inputs without the need to wait for responses from the cloud. Our experiments on five datasets demonstrate that Hybrid-RACA offers strong performance while maintaining low latency.
