DoPR: Reusable Compressed Document Prefixes for Efficient LLM Reranking

Beiya Dai, Yifan Wei, Guang Yang, Xing Shi, Xinbing Wang, Zhouhan Lin


Abstract
Large language models (LLMs) are effective rerankers, but pointwise reranking repeatedly processes the same document across different queries, causing substantial redundant document-side computation. We propose DoPR, a compressed document prefix framework that decouples offline document processing from online reranking. DoPR first selects query-independent document representations and converts them into compressed document prefix states, which are precomputed offline and reused whenever the document is retrieved. During online reranking, the model scores each query-document pair by processing only the query and scoring token, with document information supplied by the stored prefix states. This design reduces online cost through both document-side compression and cross-query prefix-state reuse. Experiments on TREC DL, BEIR, and BRIGHT with Qwen3 models from 0.6B to 8B show that DoPR achieves up to 8.0× online document-side memory reduction and up to 8.04× latency speedup, while retaining 97.1%-99.5% of the average NDCG@10 of matched full-document rerankers.
Anthology ID:
2026.findings-emnlp.316
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
6679–6693
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.316/
DOI:
Bibkey:
Cite (ACL):
Beiya Dai, Yifan Wei, Guang Yang, Xing Shi, Xinbing Wang, and Zhouhan Lin. 2026. DoPR: Reusable Compressed Document Prefixes for Efficient LLM Reranking. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 6679–6693, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
DoPR: Reusable Compressed Document Prefixes for Efficient LLM Reranking (Dai et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.316.pdf