Continual Learning on Graphs: Challenges, Solutions, and Opportunities

TL;DR

This paper provides a comprehensive review of continual learning on graphs, discussing challenges, existing methods, benchmarks, and future directions to advance the field of lifelong graph learning.

Contribution

It systematically categorizes and compares CGL algorithms, analyzes their applicability, and highlights research gaps and future opportunities.

Findings

Categorization of CGL task settings and methods

Comparison between CGL and traditional continual learning techniques

Identification of key challenges and future research directions

Abstract

Continual learning on graph data has recently attracted paramount attention for its aim to resolve the catastrophic forgetting problem on existing tasks while adapting the sequentially updated model to newly emerged graph tasks. While there have been efforts to summarize progress on continual learning research over Euclidean data, e.g., images and texts, a systematic review of progress in continual learning on graphs, a.k.a, continual graph learning (CGL) or lifelong graph learning, is still demanding. Graph data are far more complex in terms of data structures and application scenarios, making CGL task settings, model designs, and applications extremely challenging. To bridge the gap, we provide a comprehensive review of existing continual graph learning (CGL) algorithms by elucidating the different task settings and categorizing the existing methods based on their characteristics. We compare the CGL methods with traditional continual learning techniques and analyze the applicability of the traditional continual learning techniques to CGL tasks. Additionally, we review the benchmark works that are crucial to CGL research. Finally, we discuss the remaining challenges and propose several future directions. We will maintain an up-to-date GitHub repository featuring a comprehensive list of CGL algorithms, accessible at https://github.com/UConn-DSIS/Survey-of-Continual-Learning-on-Graphs.