Operational Advice for Dense and Sparse Retrievers: HNSW, Flat, or Inverted Indexes?

Fuente: arXiv
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Autore principale: Lin, Jimmy
Natura: Preprint
Pubblicazione: 2024
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author Lin, Jimmy
author_facet Lin, Jimmy
contents Practitioners working on dense retrieval today face a bewildering number of choices. Beyond selecting the embedding model, another consequential choice is the actual implementation of nearest-neighbor vector search. While best practices recommend HNSW indexes, flat vector indexes with brute-force search represent another viable option, particularly for smaller corpora and for rapid prototyping. In this paper, we provide experimental results on the BEIR dataset using the open-source Lucene search library that explicate the tradeoffs between HNSW and flat indexes (including quantized variants) from the perspectives of indexing time, query evaluation performance, and retrieval quality. With additional comparisons between dense and sparse retrievers, our results provide guidance for today's search practitioner in understanding the design space of dense and sparse retrievers. To our knowledge, we are the first to provide operational advice supported by empirical experiments in this regard.
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id arxiv_https___arxiv_org_abs_2409_06464
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Operational Advice for Dense and Sparse Retrievers: HNSW, Flat, or Inverted Indexes?
Lin, Jimmy
Information Retrieval
Practitioners working on dense retrieval today face a bewildering number of choices. Beyond selecting the embedding model, another consequential choice is the actual implementation of nearest-neighbor vector search. While best practices recommend HNSW indexes, flat vector indexes with brute-force search represent another viable option, particularly for smaller corpora and for rapid prototyping. In this paper, we provide experimental results on the BEIR dataset using the open-source Lucene search library that explicate the tradeoffs between HNSW and flat indexes (including quantized variants) from the perspectives of indexing time, query evaluation performance, and retrieval quality. With additional comparisons between dense and sparse retrievers, our results provide guidance for today's search practitioner in understanding the design space of dense and sparse retrievers. To our knowledge, we are the first to provide operational advice supported by empirical experiments in this regard.
title Operational Advice for Dense and Sparse Retrievers: HNSW, Flat, or Inverted Indexes?
topic Information Retrieval
url https://arxiv.org/abs/2409.06464