CubeGraph: Efficient Retrieval-Augmented Generation for Spatial and Temporal Data

Mingyu Yang; Wentao Li; Wei Wang

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arXiv · 2604.06616

CubeGraph: Efficient Retrieval-Augmented Generation for Spatial and Temporal Data

Mingyu Yang·Wentao Li·Wei Wang

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Abstract

Hybrid queries combining high-dimensional vector similarity search with spatio-temporal filters are increasingly critical for modern retrieval-augmented generation (RAG) systems. Existing systems typically handle these workloads by nesting vector indices within low-dimensional spatial structures, such as R-trees. However, this decoupled architecture fragments the vector space, forcing the query engine to invoke multiple disjoint sub-indices per query. This fragmentation destroys graph routing connectivity, incurs severe traversal overhead, and struggles to optimize for complex spatial boundaries. In this paper, we propose CubeGraph, a novel indexing framework designed to natively integrate vector search with arbitrary spatial constraints. CubeGraph partitions the spatial domain using a hierarchical grid, maintaining modular vector graphs within each cell. During query execution, CubeGraph dynamically stitches together adjacent cube-level indices on the fly whenever their spatial cells intersect with the query filter. This dynamic graph integration restores global connectivity, enabling a unified, single-pass nearest-neighbor traversal that eliminates the overhead of fragmented sub-index invocations. Extensive evaluations on real-world datasets demonstrate that CubeGraph significantly outperforms state-of-the-art baselines, offering superior query execution performance, scalability, and flexibility for complex hybrid workloads.

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Mingyu Yang, Wentao Li, Wei Wang. 2026-04-08. CubeGraph: Efficient Retrieval-Augmented Generation for Spatial and Temporal Data. https://arxiv.org/abs/2604.06616

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