Tuesday, 18 November 2014, 2:40PM — Bahen Centre, Room 7230

Speaker: Gunes Aluc, University of Waterloo

Title: Stress-Testing RDF Data Management Systems Using WatDiv

Abstract: As RDF data continue to be published across heterogeneous domains and integrated at Web-scale such as in the Linked Open Data (LOD) cloud, RDF data management systems are being exposed to queries that are far more diverse and workloads that are far more varied. In this talk, we answer two controversial questions: (a) are popular SPARQL benchmarks really suitable for stress-testing RDF data management systems? (b) are popular RDF data management systems really as flawless as they appear on existing benchmarks? Our experimental analysis shows that existing SPARQL benchmarks are not suitable for testing systems for diverse queries and varied workloads. To address these shortcomings, we develop the Waterloo SPARQL Diversity Test Suite (WatDiv) that provides stress testing tools for RDF data management systems. Using WatDiv, we have been able to reveal issues with existing systems that went unnoticed in evaluations using earlier benchmarks. Specifically, our experiments with five popular RDF data management systems show that they cannot deliver good performance uniformly across workloads. For some queries, there can be as much as five orders of magnitude difference between the query execution time of the fastest and the slowest system while the fastest system on one query may unexpectedly time out on another query. By performing a detailed analysis, we pinpoint these problems to specific types of queries and workloads.

Bio: Gunes Aluc is a PhD candidate at the University of Waterloo. His work focuses primarily on developing self-tuning RDF data management systems and on improving SPARQL benchmarks. In particular, he has designed and implemented chameleon-db, a self-tuning RDF data management system, and has pioneered the Waterloo SPARQL Diversity Test Suite (WatDiv) for stress-testing RDF data management systems.
Gunes obtained his MSc and BSc degrees from the Middle East Technical University, where he worked as a researcher at the Software Research and Development Center (SRDC) on various eHealth and Semantic Web related projects.
Gunes is an operagoer and often finds his inspiration in music.

 

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