Using Graph Databases

Abstract

Data in High Energy Physics (HEP) usually consist of complext complex data structures stored in relational databases and files with internal schema. Such architecture exhibits many shortcomings, which could be fixed by migrating into Graph Database storage. The paper describes basic principles of the Graph Database together with an overview of existing standards and implementations. The usefulness and usability are demonstrated using the concrete example of the Event Index of the ATLAS experiment at LHC in two approaches as the full storage (all data are in the Graph Database) and meta-storage (a layer of schema-less graph-like data implemented on top of more traditional storage). The usability, the interfaces with the surrounding framework and the performance of those solutions are discussed. The possible more general usefulness for generic experiments’ storage is also discussed.