Data Synchronization and Resynchronization for Heterogeneous Databases Replication in Middleware-based Architecture
Currently more and more web applications and telecommunication applications are required to be separation with database layer. A general solution is to employ a middleware-based architecture, including an application client tier, a DataBase Front End (DB-FE) tier, also called middleware tier, and a DataBase BackEnd (DBBE) tier. This paper mainly focuses on the issues of data synchronization and resynchronization in the case of failures for the architecture. Firstly, a synchronous update everywhere replication model and a Replication 2-Phase Commit Protocol (R2PC) are discussed, which can increase update success ratio of replication transactions through relaxing the commit constraints, and enhance DB-BEs' availability using transaction retry and discard mechanisms. Then, a novel method using request logs is suggested for data resynchronization.