실시간 주기억장치 데이터베이스 시스템을 위한 병행수행제어 기법 = Concurrency Control Algorithm for Real-time Main-Memory Database Systems

다국어 초록 (Multilingual Abstract)

Real-time database systems (RTDBS) are database systems whose transactions are associated with timing constraints such as deadlines. Therefore transaction needs to be completed by a certain deadline. Besides meeting transaction timing constraints, RTDBS need to observe data consistency constraints as well. That is to say, unlike conventional database systems, whose main objective is to provide fast average response time, RTDBS may be evaluated based on how often transactions miss their deadline, the average lateness or tardiness of late transactions, the cost incurred in transactions missing their deadlines.
Therefore, in RTDBS, transactions should be scheduled according to their criticalness and the tightness of their deadlines, even if this means sacrificing fairness and system throughput. And it always must guarantee preceding process of a high priority transaction (HPT) as 2PL-HP (two phase locking with high priority). 2PL-HP resolves a conflict through aborting or blocking of a low priority transaction (LPT). However, if HPT is eliminated in a system because of its deadline missing, an unnecessary aborting or blocking of LPT is occurred.
In this paper, we propose an efficient real-time concurrency control algorithm that prevents needless wastes of resources and eliminates unnecessary aborting or blocking of LPT. And it is shown through the performance evaluation that the proposed concurrency control algorithm outperforms the existing concurrency control algorithms.