17 Event Replication — An Alternative to Data Replication Available to Purchase

In order to address problems related to geographical distribution of application instances, data distribution has been a hot topic for years. Existing solutions are data-oriented (created by DBMS providers) and, in most cases, proven to be not quite suitable for realtime data replication. In this short paper we will present one practical case of multiple, geographically distributed application instances, using their own local databases, while real-time synchronization over a highly unreliable and expensive network is needed. The novelty of the solution described in this paper consists in transferring the replication responsibility from database level to the application logic level (business services) using a message oriented model. More precisely, each application request is implemented as a message that will be actually replicated to the other application instances. The most important issue to be solved has been found to be the global uniqueness of the business objects' identifiers.