Design And Implementation Of Database Communication Middleware

The real-time database is a very import constituent part in the distribution automation system, because the distribution automation system asks for some real-time supports. And the communication middleware provides the real-time database service interface for the top applications. So the communiction middleware is also asked for the real-time support.From the study about the architecture and the main technologies of the common communication middleware, we can realize this fact that the bottleneck of the real-time support existing in the two parts of the communication middleware which are the network communiction and the task scheduling. The bottleneck of the network communication exists in the select of the socket patterns and the management of the mutative object resources. The bottleneck of the task scheduling exists in the task done ratio.Based on the analysis and comparison of the existing techniques of the network communication, we choose the IOCP supporting for the massive connects for the base socket pattern. Then we improve the management of the mutative object resources existing in the IOCP, design and improve a framework which can choose dynamically a strategy for the management. Then we design and improve a strategy which manages the resources by the history record too.Based on the analysis and comparison of the existing task scheduling strategies, we choose the priority-driven strategy and improve the existing task scheduling algorithm. The traditional real-time scheduling algorithms pay a few attentions to the relationship existing between the tasks, for example, when many tasks have the same characteristic in a task set, but the traditional algorithms can't see it. Considering about this characteristic, the concept of the task assembly is defined, and then the task assembly DDS algorithm is designed and implemented.Finally we design and implement a test application, and the DDS and BDDS and TADDS have been tested. The simulation result proves that the TADDS is better than DDS and BDDS on the task done ratio.