No abstract

Recently, using automatic configuration tuning to improve the performance of modern database management systems (DBMSs) has attracted increasing interest from the database community. This is embodied with a number of systems featuring advanced tuning capabilities being developed. However, it remains a challenge to select the best solution for database configuration tuning, considering the large body of algorithm choices. In addition, beyond the applications on database systems, we could find more potential algorithms designed for configuration tuning. To this end, this paper provides a comprehensive evaluation of configuration tuning techniques from a broader perspective, hoping to better benefit the database community. In particular, we summarize three key modules of database configuration tuning systems and conduct extensive ablation studies using various challenging cases. Our evaluation demonstrates that the hyper-parameter optimization algorithms can be borrowed to further enhance the database configuration tuning. Moreover, we identify the best algorithm choices for different modules. Beyond the comprehensive evaluations, we offer an efficient and unified database configuration tuning benchmark via surrogates that reduces the evaluation cost to a minimum, allowing for extensive runs and analysis of new techniques.

The multi-level, heterogeneous and third-party attributes of fog computing (FC) have caused great concern in the communication security of next-generation IoT systems. This paper proposes a secure authentication scheme for dynamic key generation capability, which can enhance the security of the entire heterogeneous network without the constraints on device types, attributes and communication protocols. The communication devices exchange IDs and random numbers for registration, then generate anonymous information. During the authentication process, the cloud device (e.g., the server) uses the pseudonym information to match the recorded random numbers. Both FC devices utilize the protocol with such random numbers to generate session keys and deliver updated random numbers. Comprehensive security and performance analysis shows that the scheme can meet the security requirements of the FC architecture with lower overhead.