Rethinking Retrieval-Augmentation as Synthesis: A Query-Aware Context Merging Approach

Fuente: arXiv
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Autores principales: Guo, Jiarui, Xu, Yuemeng, Lv, Zongwei, Wang, Yangyujia, Wang, Xiaolin, Liu, Kan, Lan, Tao, Qu, Lin, Yang, Tong
Formato: Preprint
Publicado: 2026
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author Guo, Jiarui
Xu, Yuemeng
Lv, Zongwei
Wang, Yangyujia
Wang, Xiaolin
Liu, Kan
Lan, Tao
Qu, Lin
Yang, Tong
author_facet Guo, Jiarui
Xu, Yuemeng
Lv, Zongwei
Wang, Yangyujia
Wang, Xiaolin
Liu, Kan
Lan, Tao
Qu, Lin
Yang, Tong
contents Retrieval-Augmented Generation (RAG) enables Large Language Models (LLMs) to extend their existing knowledge by dynamically incorporating external information. However, practical deployment is fundamentally constrained by the LLM's finite context window, forcing a trade-off between information sufficiency and token consumption. Standard pipelines address this via a retrieve-then-select strategy, typically retaining only the top-k chunks based on relevance. Nevertheless, this approach is suboptimal: it inherently truncates critical bridging evidence located in the long tail of the relevance distribution, while simultaneously wasting the token budget on semantically redundant high-ranking chunks. In this paper, we rethink retrieval-augmentation as a dynamic optimization problem aimed at maximizing information density. We propose MergeRAG, a novel framework that shifts the paradigm from static filtering to query-aware synthesis. MergeRAG employs a scoring agent to restructure retrieved contexts through a dual-pathway mechanism: 1) Symmetric Merging, which consolidates weak signals to recover lost bridging evidence; 2) Asymmetric Merging, which utilizes entropy-guided anchoring to eliminate redundancy without sacrificing semantic integrity. We further introduce a Hierarchical Parallel Merging strategy that mitigates information loss while maximizing computational parallelism. Extensive experiments on standard benchmarks demonstrate that MergeRAG significantly outperforms state-of-the-art RAG baselines, achieving up to 13.7 points improvement in F1 score and 11.5 points in Exact Match (EM), respectively.
format Preprint
id arxiv_https___arxiv_org_abs_2603_20286
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Rethinking Retrieval-Augmentation as Synthesis: A Query-Aware Context Merging Approach
Guo, Jiarui
Xu, Yuemeng
Lv, Zongwei
Wang, Yangyujia
Wang, Xiaolin
Liu, Kan
Lan, Tao
Qu, Lin
Yang, Tong
Information Retrieval
Retrieval-Augmented Generation (RAG) enables Large Language Models (LLMs) to extend their existing knowledge by dynamically incorporating external information. However, practical deployment is fundamentally constrained by the LLM's finite context window, forcing a trade-off between information sufficiency and token consumption. Standard pipelines address this via a retrieve-then-select strategy, typically retaining only the top-k chunks based on relevance. Nevertheless, this approach is suboptimal: it inherently truncates critical bridging evidence located in the long tail of the relevance distribution, while simultaneously wasting the token budget on semantically redundant high-ranking chunks. In this paper, we rethink retrieval-augmentation as a dynamic optimization problem aimed at maximizing information density. We propose MergeRAG, a novel framework that shifts the paradigm from static filtering to query-aware synthesis. MergeRAG employs a scoring agent to restructure retrieved contexts through a dual-pathway mechanism: 1) Symmetric Merging, which consolidates weak signals to recover lost bridging evidence; 2) Asymmetric Merging, which utilizes entropy-guided anchoring to eliminate redundancy without sacrificing semantic integrity. We further introduce a Hierarchical Parallel Merging strategy that mitigates information loss while maximizing computational parallelism. Extensive experiments on standard benchmarks demonstrate that MergeRAG significantly outperforms state-of-the-art RAG baselines, achieving up to 13.7 points improvement in F1 score and 11.5 points in Exact Match (EM), respectively.
title Rethinking Retrieval-Augmentation as Synthesis: A Query-Aware Context Merging Approach
topic Information Retrieval
url https://arxiv.org/abs/2603.20286