Abstract
Studies concluded that for a variety of reasons, optimistic concurrency control appears well-suited to real-time database systems. Especially, they showed that in a real-time database system that discards tardy transactions, optimistic concurrency control outperforms locking. We show that the optimistic algorithms used in those studies incur restarts unnecessary to ensure data consistency. We present a new optimistic concurrency control algorithm that can avoid such unnecessary restarts by adjusting serialization order dynamically, and demonstrate that the new algorithm outperforms the previous ones over a wide range of system workload. It appears that this algorithm is a promising candidate for a basic concurrency control mechanism for real-time database systems.<>