PathQuery Pregel: high-performance graph query with bulk synchronous processing

High-performance graph query systems are a scalable way to mine information in Knowledge Graphs, especially when the queries benefit from a high-level expressive query language. This paper presents techniques to algorithmically compile queries expressed in a high-level language (e.g., Datalog) into a directed acyclic graph query plan and details how these queries can be run on a Pregel graph vertex-centric compute system. Our solution, called PathQuery Pregel, creates plans for any conjunctive or disjunctive queries with aggregation and negation; we describe how the query execution extracts graph results optimally while avoiding many join operations where parallel map execution is permitted. We provide details of how we scaled this system out to execute large set of queries in parallel over the Google Knowledge Graph, a graph of 70B edges, or facts; we describe our production experience with PathQuery Pregel.