Operator scale out using time utility function in big data stream processing

Many important big data applications require real-time processing of arriving data with high scalability, especially some IoT applications in where devices generate infinite data and environments are intrinsically volatile. Most of current Stream Processing Systems(SPS), like Storm or S4, often show an insufficient scalability as the architecture is based on static configurations. Although considerable research and industry effort has been invested on scale out of operators in SPS, most of them focus on how to scale out different type of operators based on an ondemand infrastructure. Few of them consider when and which operators should be scale out, as improper scale out may introduce extra overhead to the system. In this paper, we present a novel approach for finding bottleneck operator at run time and scale out only bottleneck operator. An algorithm is designed to find out bottleneck operator based on time utility function(TUF) model. The algorithm utilizes utility profit, utility penalty and utility threshold to evaluate the utility accrual of a runtime operator. With the rewarding of early completions and penalizing of missing deadline, the algorithm will scale out the operator when the utility accrual below the threshold. Experimental results show that our time-aware utility accrual approach can exactly identify and efficiently scale out the bottleneck operator at run time in data stream processing system.