Research On Several Key Issues In Heterogeneous Data Exchange Platform

In recent years, the intelligent and automatic level of Beijing Railway has improved constantly and more than10application systems such as central command system and automatic fare collection system have been built up and massive dynamic and static data have been accumulated. But these data scattered in various sectors, where the complicated operation flow, diverse data types and various storage structures all interfere the communication and cooperative work of these systems seriously, thus restricts the development of data sharing of information systems. Therefore, in order to strengthen the integration of rail transport static and dynamic data, it is necessary to establish a uniform set of rail-based database to achieve the data integration and set up uniform data standards of rail traffic sharing resources. Based on this need, we have developed the Beijing Railway data exchange platform (called "exchange platform" as below), which used the message queue mechanism to finish the data exchange through processing messages in the message queues. The paper did research on several issues in the data exchange platform and improved the existing data exchange platform. The main work is as below:1.Designing and implementing a new message processing mechanism, which uses thread pool to uniformly manage work threads which is used to process message, decreasing the number and limiting the start of work threads, thus reduce resource costs and enhance data processing efficiency.2. Designing a method to calculate the queue priority, so as to dynamically schedule the message queue to ensure that each message in the queue can be processed timely.3. Proposing an object tree model algorithm to implement the mapping from the relational schema to XML schema, therefore complete the data model conversion.4. Based on the comparison among the data types of common relational database, the paper designed a data format matching method to complete the data format match of heterogeneous systems.5. According to the above improvement strategies, the paper redesigned the whole platform and introduced every module in detail.The feature of the paper is the design of a new message processing mechanism, in which the work threads, message queues and the processor completely decoupled, and the administrator can adjust configuration parameters to dynamically adjust the platform's data exchange efficiency with great flexibility. Tests showed that, for large amount of data exchange, the new mechanism, compared with the existing mechanism, performs more stability and the platform appeared to be more efficient in message processing. On the other hand, through the conversion of data model and data format, the new platform achieves heterogeneous data exchange.