Multi-task retriever fine-tuning for domain-specific and efficient RAG
Authors: name: Patrice Béchard; name: Orlando Marquez Ayala
Published: 2025-01-08 18:05:30

Abstract: Retrieval-Augmented Generation (RAG) has become ubiquitous when deploying
Large Language Models (LLMs), as it can address typical limitations such as
generating hallucinated or outdated information. However, when building
real-world RAG applications, practical issues arise. First, the retrieved
information is generally domain-specific. Since it is computationally expensive
to fine-tune LLMs, it is more feasible to fine-tune the retriever to improve
the quality of the data included in the LLM input. Second, as more applications
are deployed in the same real-world system, one cannot afford to deploy
separate retrievers. Moreover, these RAG applications normally retrieve
different kinds of data. Our solution is to instruction fine-tune a small
retriever encoder on a variety of domain-specific tasks to allow us to deploy
one encoder that can serve many use cases, thereby achieving low-cost,
scalability, and speed. We show how this encoder generalizes to out-of-domain
settings as well as to an unseen retrieval task on real-world enterprise use
cases.