Distributed Query Decomposition in Amos II



Tore Risch

Uppsala University,  Sweden





Amos II is a distributed mediator database system where different autonomous mediator peers can be defined in terms of each other. Some of these peers will wrap different kinds of data sources with varying capabilities, while other will reconcile data from other mediators. The varying capabilities of different wrapped data sources along with the distributed architecture and the autonomy of the mediators makes query optimization costly and challenging. In this talk I will overview the distributed query decomposition methods used in Amos II and how it deals with the complexity of distributed query decomposition over distributed mediators with varying capabilities.