A Single Machine System for Querying Big Graphs with PRAM

This paper develops Planar (Plug and play PRAM), a single-machine system for graph analytics by reusing existing PRAM algorithms, without the need for designing new parallel algorithms. Planar supports both out-of-core and in-memory analytics. When a graph is too big to fit into the memory of a machine, Planar adapts PRAM to limited resources by extending a fixpoint model with multi-core parallelism, using disk as memory extension. For an in-memory task, it dedicates all available CPU cores to the task, and allows parallelly scalable PRAM algorithms to retain the property, i.e. , the more cores are available, the less runtime is taken. We develop a graph partitioning and work scheduling strategy to accommodate subgraph I/O, balance memory usage and reduce runtime, beyond traditional partitioners for multi-machine systems. Using real-life graphs, we empirically verify that Planar outperforms SOTA in-memory and out-of-core systems in efficiency and scalability.