Answering Constraint Path Queries over Graphs

TL;DR

This paper introduces a new constraint path query language for property graphs, extending RPQs with SMT constraints, and provides efficient algorithms leveraging SMT solvers, validated through implementation and empirical testing.

Contribution

It presents a novel extension of Regular Path Queries with SMT constraints and efficient algorithms that utilize SMT solvers for property graph querying.

Findings

Efficient algorithms for constraint path queries over property graphs.

Successful implementation in MillenniumDB demonstrating practical viability.

Empirical evaluation confirms the approach's effectiveness in real-world scenarios.

Abstract

Constraints are powerful declarative constructs that allow users to conveniently restrict variable values that potentially range over an infinite domain. In this paper, we propose a constraint path query language over property graphs, which extends Regular Path Queries (RPQs) with SMT constraints on data attributes in the form of equality constraints and Linear Real Arithmetic (LRA) constraints. We provide efficient algorithms for evaluating such path queries over property graphs, which exploits optimization of macro-states (among others, using theory-specific techniques). In particular, we demonstrate how such an algorithm may effectively utilize highly optimized SMT solvers for resolving such constraints over paths. We implement our algorithm in MillenniumDB, an open-source graph engine supporting property graph queries and GQL. Our extensive empirical evaluation in a real-world setting demonstrates the viability of our approach.