Research On Redundant Data Allocation In Distributed Database System

Data redundancy is the common characteristics of the distributed database. Since the distributed database is in different physical location, dispersed storage devices, in order to ensure the integrity of the data, the reliability and security of database system, the database often sacrifice the storage space and using redundant data to guarantee. In this paper, on the basis of the commonly used allocation algorithm, the author proposed a new strategy based on the type of the data and transaction, conform to the requirement for distributed database system, improve the efficiency of allocation.The effectiveness of the new strategy is mainly reflected in two aspects, one is to enhance the efficiency of the system, another is to reduce the total cost of the system. In order to reduce the total cost, consume the least amount of resource and do more work, we distributed the pieces of data. On the basis of the best fit algorithm and the heuristic add vice provisions algorithm,combining the advantages of the heuristic algorithm based on profit and cost, the author proposed the data allocation algorithm based on the type of the data and transaction to achieve better strategy to reduce the cost and improve the efficiency of the distributed system.After decades of development, the theory of distributed database has developed relatively perfect. In the distributed database system, we hope to reduce the remote data communication,and deal with the local data as more as possible, but the data size limited by the local storage capacity. So redundant data allocation problem in distributed database, still was unanimously considered the NP problems. Since that, we don’t need to get the optimal solution of the problem,only need to find a kind of algorithm that can approach to optimum, or a optimal solution to practical problems in a certain conditions. This article divide the redundant data into four types of situation from the perspective of the data types and transaction types, improve the efficiency of the distribution of data, reduce the algorithm complexity.Generally speaking, the operation method of the strategy proposed previously is mainly the same. Similarly, by initialize static distribution and redundancy of dynamic adjustment, two steps.But unlike traditional allocation algorithm, this algorithm set redundancy of data.By setting the redundancy, not only could guarantee the reliability of the system but also could reduce the storage space of the data segment. After several experiments, selected the limit range. By setting the limit, on the one hand it could ensure that the data redundancy copy to guarantee the reliability of the system, on the other hand, can reduce the redundant data fragments of the waste system space.The algorithm proposed by this paper provide a better allocation strategy of distributedsystem. Experiments show that this algorithm can control the redundancy, shorten the time of distribution and improve the efficiency of the system.