The admission control has been proposed to re- solve the system overloading problem. With admis- sion control, when the system is near an overloading condition, new queries are either throttled (e.g., [8]) or rejected (e.g., [15]) until the system condition im- proves. Although existing admission control tech- niques are helpful to alleviate system overloading, they do not work directly toward the main goal of cloud service providers—namely to maximize their profits by satisfying different SLAs.