A non-blocking locking method and performance evaluation on network of workstations

A network of workstation (NOW) can act as a single and scalable powerful computer by building a parallel and distributed computing platform on top of it. WAKASHI is such a platform system that supports persistent object management and makes full use of resources of NOW for high performance transaction processing. One of the main difficulties to overcome is the bottleneck caused by concurrency control mechanism. Therefore, a non-blocking locking method is designed, by adopting several novel techniques to make it outperform the other typical locking methods such as 2PL: 1) an SDG (Semantic Dependency Graph) based non-blocking locking protocol for fast transaction scheduling; 2) a massively virtual memory based backup-page undo algorithm for fast restart; and 3) a multi-processor and multi-thread based transaction manager for fast execution. The new mechanisms have been implemented in WAKASHI and the performance comparison experiments with 2PL and DWDL have been done. The results show that the new method can outperform 2PL and DWDL under certain conditions. This is meaningful for choosing effective concurrency control mechanisms for improving transaction-processing performance in NOW environments.