Studies on High-Speed Transaction Machines Utilizing Hardware Concurrency Control Mechanisms

点击翻译按钮获取中文摘要

In the first year of this project, basic surveys on architectures and concurrency control mechanisms were initiated. In the next year, concurrency control for hotspot data were studied through simulations, and the hardware for the backup mechanism was designed. The final year was spent for implementation of the machine and publication of the results.The major results are summarized as follows.1) Theoretical studies were carried out on concurrency control mechanisms which can handle heterogeneous data and long term transactions under the serializability restricted with response time.2) A new method was designed for concurrency control in database systems handling hotspot data and non-hotspot data separately, which had not been studied before.3) A concurrency control mechanism for the parallel transaction model and its hardware implementation were studied. This research disclosed the problem of increased deadlocks in this architecture. A measure for this effect was proposed, and its hardware design was completed.4) A continuously backuped memory was designed. Since the backup cost for hotspot data is expensive, research and development was initiated for a simultaneous hardware backup mechanism which does not slow down system operations. A continuously backuped disk unit was also designed. These mechanisms were integrated in the design of the target system which requires low overhead for backup.5) A hardware logging system was designed. Since logging of database operations occupies nearly 50% of the total operation time of some systems, the hardware monitor for CPU buses is now under development.