ALLOCATING DATA AND OPERATIONS TO NODES IN DISTRIBUTED DATABASE DESIGN

The allocation of data and operations to nodes in a computer communications network is a critical issue in distributed database design, An efficient distributed database design must trade off performance and cost among retrieval and update activities at the various nodes, It must consider the concurrency control mechanism used as well as capacity constraints at nodes and on links in the network, It must determine where data will be allocated, the degree of data replication, which copy of the data will be used for each retrieval activity, and where operations such as select, project, join, and union will be performed, We develop a comprehensive mathematical modeling approach for this problem, The approach first generates units of data (file fragments) to be allocated from a logical data model representation and a characterization of retrieval and update activities, Retrieval and up date activities are then decomposed into relational operations on these fragments. Both fragments and operations on them are then allocated to nodes using a mathematical modeling approach, The mathematical model considers network communication, local processing, and data storage costs, A genetic algorithm is developed to solve this mathematical formulation.