A Non-Blocking Locking Method and Performance Evaluation on Network of Workstations

A network of workstation (NOW) can act as a single and scalablepowerful computer by building a parallel and distributed computingplatform on top of it. WAKASHI is such a platform system that supportspersistent object management and makes full use of resources of NOWfor high performance transaction processing. One of the maindifficulties to overcome is the bottleneck caused by concurrencycontrol mechanism. Therefore, a non-blocking locking method is designed,by adopting several novel techniques to make it outperform the othertypical 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 forfast restart; and 3) a multi-processor and multi-thread basedtransaction manager for fast execution. The new mechanisms have beenimplemented in WAKASHI and the performance comparison experiments with2PL and DWDL have been done. The results show that the new method canoutperform 2PL and DWDL under certain conditions. This is meaningfulfor choosing effective concurrency control mechanisms for improvingtransaction processing performance in NOW environments.