关键词: 云工作流, 工作流引擎, 无状态, 调度算法

Abstract: The execution of business process requests requires the workflow engine to parse the process definition document to build an in-memory process model.However,the current stateless cloud workflow scheduling does not consider the distribution of process model in engine memory,which leads to the repeated parsing of process documents by the engine,resulting in the degradation of system performance.For this reason,by taking the stateless workflow engine Activiti as the research object,a scheduling algorithm was proposed for task requests of stateless cloud workflow process instances based on Activiti engine process model caching mechanism,which made requests under the same process definition be allocated to few engines as much as possible.Simulation results showed that the proposed algorithm could improve the cache hit ratio of engine and reduce the number of database query and process definition document parsing under the premise of engine instances load balancing,so as to reduce the request response time and save the resources on the cloud.

Key words: cloud workflow, workflow engine, stateless, scheduling algorithm