Processing SPARQL Property Path Queries Online with Web Preemption

Julien Aimonier-Davat, hala skaf-molli, Pascal Molli

Keywords: Semantic Web, Semantic Data Management, SPARQL, Property Paths, Public SPARQL endpoints

Abstract:

SPARQL property path queries provide a succinct way to write complex
navigational queries over RDF knowledge graphs. However, the
evaluation of these queries over online knowledge graphs such as
DBPedia or Wikidata is often interrupted by quotas, returning no
results or partial results. To ensure complete results, property path queries
are evaluated client-side. Smart clients decompose property path queries into
subqueries for which complete results are ensured. The granularity of the decomposition
depends on the expressivity of the server. Whatever the decomposition,
it could generate a high number of subqueries, a large
data transfer, and finally delivers poor performance.
In this paper, we extend a preemptable SPARQL server with a partial
transitive closure operator (PTC) based on a depth limited search algorithm. We
show that a smart client using the PTC operator is able to process
SPARQL property path online and deliver complete results.
Experimental results demonstrate that our approach outperforms existing smart
client solutions in terms of HTTP calls, data transfer and query
execution time.

Subtrack: Ontologies and Reasoning

First Author Is Student: Yes