A Task-Type Aware Transaction Scheduling Algorithm in J2EE

Abstract

A large number of J2EE applications use entity beans as their application persistence mechanism, while current J2EE scheduling to entity beans is still a simple First-Come First-Served (FCFS) policy. Due to this simple policy, the scheduling does not distinguish the key transactions from the trivial ones. A task-type aware scheduling algorithm should be adopted to provide better service for key transactions. However, some characteristics of J2EE middleware transaction processing, such as the absence of necessary scheduling information and the interactive executing model, made it impossible to apply the traditional priority-driven scheduling algorithms. This paper puts forward a scheduling algorithm named TMPBP, which offers a new dynamic priority assignment algorithm HRS that can recognize the key tasks at runtime heuristically. Additionally, TMPBP add some extra techniques to the traditional concurrency control policies according to the features of J2EE. The algorithm is proven to be safe and will not produce starvation or priority inversion. The experimental evaluations indicated that TMPBP improves the Quality of Service (QoS) of key tasks effectively, especially when the server is under a heavy load.