MAST: Towards Efficient Analytical Query Processing on Point Cloud Data

The proliferation of 3D scanning technology, particularly within autonomous driving, has led to an exponential increase in the volume of Point Cloud (PC) data. Given the rich semantic information contained in PC data, deep learning models are commonly employed for tasks such as object queries. However, current query systems that support PC data types do not process queries on semantic information. Consequently, there is a notable gap in research regarding the efficiency of invoking deep models for each PC data query, especially when dealing with large-scale models and datasets. To address this issue, this work aims to design an efficient approximate approach for supporting PC analysis queries, including PC retrieval and aggregate queries. In particular, we propose a novel framework that delivers approximate query results efficiently by sampling core PC frames within a constrained budget, thereby minimizing the reliance on deep learning models. This framework is underpinned by rigorous theoretical analysis, providing error-bound guarantees for the approximate results if the sampling policy is preferred. To achieve this, we incorporate a multi-agent reinforcement learning-based approach to optimize the sampling procedure, along with an innovative reward design leveraging spatio-temporal PC analysis. Furthermore, we exploit the spatio-temporal characteristics inherent in PC data to construct an index that accelerates the query process. Extensive experimental evaluations demonstrate that our proposed method, MAST, not only achieves accurate approximate query results but also maintains low query latency, ensuring high efficiency.