Elastic Index Selection for Label-Hybrid AKNN Search

Fuente: arXiv
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Main Authors: Yang, Mingyu, Xia, Wenxuan, Li, Wentao, Wong, Raymond Chi-Wing, Wang, Wei
Format: Preprint
Published: 2025
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_version_ 1866912757080653824
author Yang, Mingyu
Xia, Wenxuan
Li, Wentao
Wong, Raymond Chi-Wing
Wang, Wei
author_facet Yang, Mingyu
Xia, Wenxuan
Li, Wentao
Wong, Raymond Chi-Wing
Wang, Wei
contents Real-world vector embeddings are usually associated with extra labels, such as attributes and keywords. Many applications require the nearest neighbor search that contains specific labels, such as searching for product image embeddings restricted to a particular brand. A straightforward approach is to materialize all possible indices according to the complete query label workload. However, this leads to an exponential increase in both index space and processing time, which significantly limits scalability and efficiency. In this paper, we leverage the inclusion relationships among query label sets to construct partial indexes, enabling index sharing across queries for improved construction efficiency. We introduce \textit{elastic factor} bounds to guarantee search performance and use the greedy algorithm to select indices that meet the bounds, achieving a tradeoff between efficiency and space. Meanwhile, we also designed the algorithm to achieve the best elastic factor under a given space limitation. Experimental results on multiple real datasets demonstrate that our algorithm can achieve near-optimal search performance, achieving up to 10x-500x search efficiency speed up over state-of-the-art approaches. Our algorithm is highly versatile, since it is not constrained by index type and can seamlessly integrate with existing optimized libraries.
format Preprint
id arxiv_https___arxiv_org_abs_2505_03212
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Elastic Index Selection for Label-Hybrid AKNN Search
Yang, Mingyu
Xia, Wenxuan
Li, Wentao
Wong, Raymond Chi-Wing
Wang, Wei
Databases
Real-world vector embeddings are usually associated with extra labels, such as attributes and keywords. Many applications require the nearest neighbor search that contains specific labels, such as searching for product image embeddings restricted to a particular brand. A straightforward approach is to materialize all possible indices according to the complete query label workload. However, this leads to an exponential increase in both index space and processing time, which significantly limits scalability and efficiency. In this paper, we leverage the inclusion relationships among query label sets to construct partial indexes, enabling index sharing across queries for improved construction efficiency. We introduce \textit{elastic factor} bounds to guarantee search performance and use the greedy algorithm to select indices that meet the bounds, achieving a tradeoff between efficiency and space. Meanwhile, we also designed the algorithm to achieve the best elastic factor under a given space limitation. Experimental results on multiple real datasets demonstrate that our algorithm can achieve near-optimal search performance, achieving up to 10x-500x search efficiency speed up over state-of-the-art approaches. Our algorithm is highly versatile, since it is not constrained by index type and can seamlessly integrate with existing optimized libraries.
title Elastic Index Selection for Label-Hybrid AKNN Search
topic Databases
url https://arxiv.org/abs/2505.03212