摘要：In this paper, it combines the dynamic nature of grid services with the capabilities alternative of real-time transactions. First of all, the grid real-time transaction model based on function equivalent service is defined .The model supports the joint implementation by a number of function equivalent services which own the same transaction, and allows grid services to join or exit the transaction’s execution dynamically. Secondly, the Share and Compete (S&C) concurrency control protocol is proposed. It mainly solves resource conflicts between function equivalent services of the internal transaction in the grid real-time transaction model based on function equivalent service. In the system environment, the transaction as a whole unit to share resources. The function equivalent service can’t change the properties of a transaction, such as atomicity, consistency, isolation, durability and so on. Because function equivalent services execute in parallel, it ensures the high success rate. Competitive submitting improves the immediacy of the system. When multiple functionally equivalent services to perform the same transaction, the one with superior performance and light service load will be the first to return the results. It ensures real-time requirements strictly. Grid services can dynamically join or exit the transaction’s execution. It relaxes to conditions of aborting and reduces miss rate of the transaction. Finally, the feasibility of S&C protocol is to be analyzed base on the formal Petri net and experimental verification.
关键词：Grid; Function Equivalent Service; S&C; Concurrency Control Protocol
