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Main Authors: Zhao, Ziliang, Xue, Bi, Lin, Emma, Lu, Tianqi, Zhou, Mengjiao, Vartak, Kaustubh, Ali-Zade, Shakhzod, Li, Tao, Kuang, Bin, Jian, Rui, Wen, Bin, van der Staay, Dennis, Bao, Yixin, Li, Eddy, Deng, Chao, Wei, Henry, Liu, Songbin, Wang, Qifan, Ren, Kai
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2602.17050
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author Zhao, Ziliang
Xue, Bi
Lin, Emma
Lu, Tianqi
Zhou, Mengjiao
Vartak, Kaustubh
Ali-Zade, Shakhzod
Li, Tao
Kuang, Bin
Jian, Rui
Wen, Bin
van der Staay, Dennis
Bao, Yixin
Li, Eddy
Deng, Chao
Wei, Henry
Liu, Songbin
Wang, Qifan
Ren, Kai
author_facet Zhao, Ziliang
Xue, Bi
Lin, Emma
Lu, Tianqi
Zhou, Mengjiao
Vartak, Kaustubh
Ali-Zade, Shakhzod
Li, Tao
Kuang, Bin
Jian, Rui
Wen, Bin
van der Staay, Dennis
Bao, Yixin
Li, Eddy
Deng, Chao
Wei, Henry
Liu, Songbin
Wang, Qifan
Ren, Kai
contents Embedding tables are critical components of large-scale recommendation systems, facilitating the efficient mapping of high-cardinality categorical features into dense vector representations. However, as the volume of unique IDs expands, traditional hash-based indexing methods suffer from collisions that degrade model performance and personalization quality. We present Multi-Probe Zero Collision Hash (MPZCH), a novel indexing mechanism based on linear probing that effectively mitigates embedding collisions. With reasonable table sizing, it often eliminates these collisions entirely while maintaining production-scale efficiency. MPZCH utilizes auxiliary tensors and high-performance CUDA kernels to implement configurable probing and active eviction policies. By retiring obsolete IDs and resetting reassigned slots, MPZCH prevents the stale embedding inheritance typical of hash-based methods, ensuring new features learn effectively from scratch. Despite its collision-mitigation overhead, the system maintains training QPS and inference latency comparable to existing methods. Rigorous online experiments demonstrate that MPZCH achieves zero collisions for user embeddings and significantly improves item embedding freshness and quality. The solution has been released within the open-source TorchRec library for the broader community.
format Preprint
id arxiv_https___arxiv_org_abs_2602_17050
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Multi-Probe Zero Collision Hash (MPZCH): Mitigating Embedding Collisions and Enhancing Model Freshness in Large-Scale Recommenders
Zhao, Ziliang
Xue, Bi
Lin, Emma
Lu, Tianqi
Zhou, Mengjiao
Vartak, Kaustubh
Ali-Zade, Shakhzod
Li, Tao
Kuang, Bin
Jian, Rui
Wen, Bin
van der Staay, Dennis
Bao, Yixin
Li, Eddy
Deng, Chao
Wei, Henry
Liu, Songbin
Wang, Qifan
Ren, Kai
Machine Learning
Embedding tables are critical components of large-scale recommendation systems, facilitating the efficient mapping of high-cardinality categorical features into dense vector representations. However, as the volume of unique IDs expands, traditional hash-based indexing methods suffer from collisions that degrade model performance and personalization quality. We present Multi-Probe Zero Collision Hash (MPZCH), a novel indexing mechanism based on linear probing that effectively mitigates embedding collisions. With reasonable table sizing, it often eliminates these collisions entirely while maintaining production-scale efficiency. MPZCH utilizes auxiliary tensors and high-performance CUDA kernels to implement configurable probing and active eviction policies. By retiring obsolete IDs and resetting reassigned slots, MPZCH prevents the stale embedding inheritance typical of hash-based methods, ensuring new features learn effectively from scratch. Despite its collision-mitigation overhead, the system maintains training QPS and inference latency comparable to existing methods. Rigorous online experiments demonstrate that MPZCH achieves zero collisions for user embeddings and significantly improves item embedding freshness and quality. The solution has been released within the open-source TorchRec library for the broader community.
title Multi-Probe Zero Collision Hash (MPZCH): Mitigating Embedding Collisions and Enhancing Model Freshness in Large-Scale Recommenders
topic Machine Learning
url https://arxiv.org/abs/2602.17050