Answering Regular Path Queries on Workflow Provenance

TL;DR

This paper introduces an efficient method for answering regular path queries on workflow provenance graphs with recursion, leveraging reachability labels and query decomposition to improve performance.

Contribution

It presents a novel approach that decomposes queries into safe subqueries, enabling constant-time path existence checks and reducing the number of subqueries needed.

Findings

Significant reduction in subqueries compared to existing methods

Constant-time decision for safe subqueries using reachability labels

Experimental results show improved query evaluation performance

Abstract

This paper proposes a novel approach for efficiently evaluating regular path queries over provenance graphs of workflows that may include recursion. The approach assumes that an execution g of a workflow G is labeled with query-agnostic reachability labels using an existing technique. At query time, given g, G and a regular path query R, the approach decomposes R into a set of subqueries R1, ..., Rk that are safe for G. For each safe subquery Ri, G is rewritten so that, using the reachability labels of nodes in g, whether or not there is a path which matches Ri between two nodes can be decided in constant time. The results of each safe subquery are then composed, possibly with some small unsafe remainder, to produce an answer to R. The approach results in an algorithm that significantly reduces the number of subqueries k over existing techniques by increasing their size and complexity, and that evaluates each subquery in time bounded by its input and output size. Experimental results demonstrate the benefit of this approach.