Stress-Testing Remote Model Querying APIs for Relational and Graph-Based Stores

Research output: Contribution to journalArticlepeer-review


Recent research in scalable model-driven engineering now allows very large models to be stored and queried. Due to their size, rather than transferring such models over the network in their entirety, it is typically more efficient to access them remotely using networked services (e.g. model repositories, model indexes). Little attention has been paid so far to the nature of these services, and whether they remain responsive with an increasing number of concurrent clients. This paper extends a previous empirical study on the impact of certain key decisions on the scalability of concurrent model queries on two domains, using an Eclipse Connected Data Objects model repository, four configurations of the Hawk model index and a Neo4j-based configuration of the NeoEMF model store. The study evaluates the impact of the network protocol, the API design, the caching layer, the query language and the type of database, and analyses the reasons for their varying levels of performance. The design of the API was shown to make a bigger difference compared to the network protocol (HTTP/TCP) used. Where available, the query-specific indexed and derived attributes in Hawk outperformed the comprehensive generic caching in CDO. Finally, the results illustrate the still ongoing evolution of graph databases: two tools using different versions of the same backend had very different performance, with one slower than CDO and the other faster than it.
Original languageEnglish
Pages (from-to)1047-1075
Number of pages29
JournalSoftware and Systems Modeling
Issue number2
Early online date30 Jun 2017
Publication statusPublished - 4 Apr 2019

Bibliographical note

© The Author(s) 2017.

Funding Information:
This research was part supported by the EPSRC, through the Large-Scale Complex IT Systems project (EP/F001096/1), and by the EU through the MONDO FP7 STREP project (#611125). We would also like to thank Gwendal Daniel for his support on the use of Mogwa? and NeoEMF. The research data supporting this publication are available on

Publisher Copyright:
© 2017, The Author(s).


  • API design
  • Collaborative modelling
  • Model persistence
  • NoSQL storage
  • Relational databases
  • Remote model querying
  • Stress testing

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