International Technology Alliance Collaboration System (ITACS)
The cost of query evaluation in a Dynamic Distributed Federated Databases (DDFD) depends on the topology connecting the database nodes together. Different topologies provide opportunities to adopt a variety of query optimization strategies and topology also influences the efficiency of these strategies. The authors describe a number of strategies to optimize join queries and then derive cost estimation formulae. They use these to visualize and explore the performance of join queries in different distributed topologies.