Coordinating services for accessing and processing data in dynamic environments

This paper presents an approach and an associated system named Hypatia for accessing and processing data by coordinating services in dynamic environments. A dynamic environment consists of applications, servers and devices that can be static and nomad, and that produce or consume data on demand (e.g., online applications, Web-hosted DBMS) or continuously (messaging systems, mobile services). In such an environment, data are hidden behind services that export application programming interfaces (API) through heterogeneous networks and that provide functions for retrieving and processing data. In order to have an aggregated and integrated view of the dynamic environment at every moment (e.g., accessing Google's agenda service and feeding a Twitter service for continuously locating friends as we all stroll in a city), data consumers have to execute sets of service calls, i.e., subscribe to continuous data producers, aggregate results and feed other services and then obtain results and eventually start over again. No off-the-shelf DBMS provides such service oriented querying approach including continuous, one-shot, mobile and static query evaluation. Our work introduces the notion of hybrid query that declaratively expresses data consumers requirements and an associated query evaluator, Hypatia, that executes data oriented query service coordinations; taking advantage of the services available in the network (data providers and devices computing capacity) and yielding the query result.