ALLOCATING DATA AND OPERATIONS TO NODES IN DISTRIBUTED DATABASE DESIGN

The allocation of data and operations to nodes in a computer communica tions network is a critical issue in distributed database design, An e fficient distributed database design must trade off performance and co st among retrieval and update activities at the various nodes, It must consider the concurrency control mechanism used as well as capacity c onstraints at nodes and on links in the network, It must determine whe re data will be allocated, the degree of data replication, which copy of the data will be used for each retrieval activity, and where operat ions such as select, project, join, and union will be performed, We de velop a comprehensive mathematical modeling approach for this problem, The approach first generates units of data (file fragments) to be all ocated 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. Bot h fragments and operations on them are then allocated to nodes using a mathematical modeling approach, The mathematical model considers netw ork communication, local processing, and data storage costs, A genetic algorithm is developed to solve this mathematical formulation.