Research And Implementation For Maintaining Replica Consistency In Distributed Heterogeneous Databases

With the rapid development of computer technologies, data center has played a more important role in information system. The method that store data in single position we used before can not satisfy the requirement of disaster tolerance and backup for system. Currently, data duplications need to be stored at remote databases for the sake of continuous availability and reliability. Consequently, the consistency problem of these duplications is becoming the main issue in research of disaster-tolerance system.In this paper, we analyze the consistency problem of duplications in heterogeneous database systems and make a comparison on current technologies of consistency maintenance. We provide a method base on Transaction-Redo technology and design a subsystem called DRCS(Data Replica Consistency System) to maintain the data consistency in practical disaster-tolerance system. My research makes following contributions:(1) Analyze the maintenance technologies for data consistency, make a comparison on them for disaster-tolerance system, and provide a method based on Transaction-Redo technology to maintain the consistency of data duplications in heterogeneous database systems.(2) Based on the Transaction-Redo technology, design a subsystem called DRCS to maintain the consistency of crucial data duplications for disaster-tolerance systems.(3) Prove that the result of serial execution by the order of concurrent transactions commit is equal to the result of concurrent execution.(4) Implement the DRCS to maintain the consistency of crucial data duplications for the actual disaster-tolerance systems.(5) After the implementation of the DRCS, make some tests to measure the availability and reliability of it.