Budget-Constrained Online Retrieval-Augmented Generation: The Chunk-as-a-Service Model

Fuente: arXiv
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Hauptverfasser: Al-Maliki, Shawqi, Gharaibeh, Ammar, Rahouti, Mohamed, Amin, Mohammad Ruhul, Abdallah, Mohamed, Qadir, Junaid, Al-Fuqaha, Ala
Format: Preprint
Veröffentlicht: 2026
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author Al-Maliki, Shawqi
Gharaibeh, Ammar
Rahouti, Mohamed
Amin, Mohammad Ruhul
Abdallah, Mohamed
Qadir, Junaid
Al-Fuqaha, Ala
author_facet Al-Maliki, Shawqi
Gharaibeh, Ammar
Rahouti, Mohamed
Amin, Mohammad Ruhul
Abdallah, Mohamed
Qadir, Junaid
Al-Fuqaha, Ala
contents Large Language Models (LLMs) have revolutionized the field of natural language processing. However, they exhibit some limitations, including a lack of reliability and transparency: they may hallucinate and fail to provide sources that support the generated output. Retrieval-Augmented Generation (RAG) was introduced to address such limitations in LLMs. One popular implementation, RAG-as-a-Service (RaaS), has shortcomings that hinder its adoption and accessibility. For instance, RaaS pricing is based on the number of submitted prompts, without considering whether the prompts are enriched by relevant chunks, i.e., text segments retrieved from a vector database, or the quality of the utilized chunks (i.e., their degree of relevance). This results in an opaque and less cost-effective payment model. We propose Chunk-as-a-Service (CaaS) as a transparent and cost-effective alternative. CaaS includes two variants: Open-Budget CaaS (OB-CaaS) and Limited-Budget CaaS (LB-CaaS), which is enabled by our ``Utility-Cost Online Selection Algorithm (UCOSA)''. UCOSA further extends the cost-effectiveness and the accessibility of the OB-CaaS variant by enriching, in an online manner, a subset of the submitted prompts based on budget constraints and utility-cost tradeoff. Our experiments demonstrate the efficacy of the proposed UCOSA compared to both offline and relevance-greedy selection baselines. In terms of the performance metric-the number of enriched prompts (NEP) multiplied by the Average Relevance (AR)-UCOSA outperforms random selection by approximately 52% and achieves around 75% of the performance of offline selection methods. Additionally, in terms of budget utilization, LB-CaaS and OB-CaaS achieve higher performance-to-budget ratios of 140% and 86%, respectively, compared to RaaS, indicating their superior efficiency.
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id arxiv_https___arxiv_org_abs_2604_26981
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Budget-Constrained Online Retrieval-Augmented Generation: The Chunk-as-a-Service Model
Al-Maliki, Shawqi
Gharaibeh, Ammar
Rahouti, Mohamed
Amin, Mohammad Ruhul
Abdallah, Mohamed
Qadir, Junaid
Al-Fuqaha, Ala
Information Retrieval
Machine Learning
Large Language Models (LLMs) have revolutionized the field of natural language processing. However, they exhibit some limitations, including a lack of reliability and transparency: they may hallucinate and fail to provide sources that support the generated output. Retrieval-Augmented Generation (RAG) was introduced to address such limitations in LLMs. One popular implementation, RAG-as-a-Service (RaaS), has shortcomings that hinder its adoption and accessibility. For instance, RaaS pricing is based on the number of submitted prompts, without considering whether the prompts are enriched by relevant chunks, i.e., text segments retrieved from a vector database, or the quality of the utilized chunks (i.e., their degree of relevance). This results in an opaque and less cost-effective payment model. We propose Chunk-as-a-Service (CaaS) as a transparent and cost-effective alternative. CaaS includes two variants: Open-Budget CaaS (OB-CaaS) and Limited-Budget CaaS (LB-CaaS), which is enabled by our ``Utility-Cost Online Selection Algorithm (UCOSA)''. UCOSA further extends the cost-effectiveness and the accessibility of the OB-CaaS variant by enriching, in an online manner, a subset of the submitted prompts based on budget constraints and utility-cost tradeoff. Our experiments demonstrate the efficacy of the proposed UCOSA compared to both offline and relevance-greedy selection baselines. In terms of the performance metric-the number of enriched prompts (NEP) multiplied by the Average Relevance (AR)-UCOSA outperforms random selection by approximately 52% and achieves around 75% of the performance of offline selection methods. Additionally, in terms of budget utilization, LB-CaaS and OB-CaaS achieve higher performance-to-budget ratios of 140% and 86%, respectively, compared to RaaS, indicating their superior efficiency.
title Budget-Constrained Online Retrieval-Augmented Generation: The Chunk-as-a-Service Model
topic Information Retrieval
Machine Learning
url https://arxiv.org/abs/2604.26981