Abstract
Data are naturally produced at different locations and hence stored on different DBMSes. To maximize the value of the collected data, today’s users combine data from different sources. Research in data integration has proposed the Mediator-Wrapper (MW) architecture to enable ad-hoc querying processing over multiple sources. The MW approach is desirable for users, as they do not need to deal with heterogeneous data sources. However, from a query processing perspective, the MW approach is inefficient : First, one needs to provision the mediating execution engine with hardware resources. Second, during query processing, data gets “centralized” within the mediating engine, which causes redundant data movement. In previous work we proposed in-situ cross-database query processing, a paradigm for federated query processing without a mediating engine. Our approach aims to leverage existing systems, such that it is not necessary to maintain an additional federated query engine, to increase the runtime performance and to decrease the data movement. In this demonstration we showcase XDB, our prototype for in-situ cross-database query processing. We demonstrate several aspects of XDB, i.e. the cross-database environment, our optimization techniques, and its decentralized execution phase.
