The Research And Implementation Of Pipeline Based Processing And Concurrency Control Of Distributed Transaction

In distributed environment, the sub-transactions of a transaction often execute on different nodes. To ensure the ACID properties of distributed transactions,currently the most widely used commit protocol is the two-phase commit protocol and the extened three-phase commit protocol. However, with the development of web service, there are some new problems, for example, the resource concurrency in the web service environment, the long-running transactions, and so on. This paper proposes a pipeline processing model of serial long transactions and the concurrency model of distributed transactions according to these new problems, based on which a grid transaction processing platform and the application system are constructed.The long transactions in web service environment always take a long time and lock the resource, which will bring down the efficiency of the transaction processing. The normal solution is the compensating transaction, which permits the sub-transactions to commit independently. Once the trasanction fails, The compensating transaction with the opposite effect. However, the compensating transaction is difficult or even impossible to create in many cases. This paper proposed a novel pipeline-based processing model for the serial long transactions, which pipelines the transaction processing and improves the performance evidently without compensating transaction.According to the two-phase commit protocol, there will be deadlock when the sub-transactions of distributed transactions request the same resource, including the local deadlock and the global deadlock. This paper proposes a new concurrent solution based on resource replica for the local deadlock, which allows the sub-transactions to execute serially on the resource replica and satisfies the atomicy and the coherency without deadlock. For the global deadlock, this paper proposes the resource reserving machanism based on time stamp, which adds a new resource reserving phase beefore the two phases of 2PC protocol. The new machanism could detect and avoid the dealock before executing the transactions, inhence improves the efficiency of transaction processing. Besides, the time stamp could reduce the starvation of the transaction.This paper also introduces the design and implementation of the service oriented grid transaction processing platform and application system. As the middleware between the grid service and application, the grid transaction processing system provide a uniform interface for the grid transaction, including the atomic transaction, the long transaction, the real-time transaction, the serial long transaction and so on. The application system on it consists of the bank transfering system, the travel planning system, the stock trading system, and the order processing system.