An Extensive Experimental Study of Indexes in Continuous Subgraph Matching: [Experiments & Analysis]

Continuous subgraph matching (CSM), which finds incremental matches of a query graph for each update in a dynamic graph, has gained significant research attention. Most CSM algorithms follow a common indexing-enumeration paradigm: they first use indexes to identify candidate vertices and edges for the query graph, and then enumerate matches based on these candidates. Although there have been several comprehensive experimental analyses of CSM algorithms, they tend to evaluate CSM algorithms holistically, obscuring the distinct contributions of the indexing and enumeration methods to overall performance. In this paper, we decouple the indexing method and enumeration method of existing CSM algorithms, and focus on the comparison of indexing methods. Our experimental results offer guidance on index selection across different scenarios, serving as a reference for future research and industrial applications. They further reveal the relative importance of different index components, informing strategies to discard less essential parts when memory is limited. Additionally, we show that the commonly used candidate count metric may underestimate the filtering effectiveness of certain indexes, suggesting that future research should adopt more reliable evaluation metrics.