Materialization of Redesigned Distributed Relational Databases 1 Kamalakar Karlapalem

The changes in the distributed database environment during its lifetime necessitate a redesign of the distributed databases so as to keep the performance of the applications/transactions from degrading. Till now most of the work in distributed database design dealt with developing better fragmentation and allocation algorithms. This paper introduces an hitherto unexplored step in distributed database design dealing with the materialization of a new design after the redesign for an existing populated distributed relational database. We de ne materialization of a distributed database design as a process of global restructuring of the populated local databases in order to achieve conformance with the logical de nition of the distributed database. Work on distributed database design dealing with mixed fragmentation facilitates the development of a formal basis for materializing distributed database designs. We present two approaches (Query Generator method and Operator method) to achieve the solution. We develop a cost model for evaluating these two approaches and present a multiple query optimization algorithm to improve the e ciency of the query generator approach. These algorithms need to be initiated by the distributed database administrator to automatically materialize redesigned distributed databases. The operator method is suitable for incremental materialization whereas the query generator method is suitable for one-time materialization of the distributed databases.