Simulation study of concurrency control methods for parallel online transaction processing systems

摘要

In an online transaction processing (OLTP) system, concurrent access to data becomes a major issue, especially when a database is composed of a large number of frequently accessed and modified data under a multi-user environment. For an example, in a stock trading system or an airline reservation system, data are updated frequently and at the same time, a large number of queries are often made to support business decisions. Therefore, a database system that can provide a high degree of concurrency is of ultimate importance. In order to study concurrency control methods for parallel OLTP systems under a realistic workload, we developed a parallel OLTP simulator, which follows the X/Open Distributed Transaction Processing (DTP) model and uses TPC-A/TPC-C as workloads. With this simulator we can evaluate the performance of different concurrency control methods. By now, we have implemented two methods in this simulator: two phase locking (2PL) and 2PLE, and we have made a comparison between these two methods under different workloads.