The prediction of the future workload of applications is an essential step guiding resource provisioning in cloud environments. In our previous works, we proposed two prediction models based on pattern mining. This paper builds on our previous experience and focuses on the issue of time and space complexities of the prediction model. Specifically, it presents a general approach to improve the efficiency of the pattern mining engine, which leads to improving the efficiency of the predictors. The approach is composed of two steps: (1) Firstly, to improve space complexity, redundant occurrences of patterns are defined and algorithms are suggested to identify and omit them. (2) To improve time complexity, a new data structure, called closed pattern backward tree, is presented for mining closed patterns directly. The approach not only improves the efficiency of our predictors, but also can be employed in different fields of pattern mining. The performance of the proposed approach is investigated based on real and synthetic workloads of cloud. The experimental results show that the proposed approach could improve the efficiency of the pattern mining engine significantly in comparison to common methods to extract closed patterns.
