Transaction Management in a Heterogeneous Database Environment

小行星9221301 异构数据库环境中的事务管理 今年是连续三年获奖的第一年。 多数据库系统（MDBS）由许多运行不同商业数据库管理系统（DBMS）的站点组成。MDBS的目标是集成DBMS，允许应用程序访问来自单个DBMS的数据，而不需要修改它们。多数据库系统中的自治用户组织通常在DBMS上投入了大量资金，并且可能不愿意修改或失去对DBMS的控制。因此，必须开发多数据库事务处理方法，允许高度的本地自治，但以一致和可靠的方式支持用户的数据。本研究探讨如何管理和保证数据的一致性驻留在异构数据库管理系统，同时坚持参与数据库管理系统的自治要求。本文提出的MDBS事务管理方案具有以下特点：（1）适应MDBS环境，现有的基于保持事务原子性和可串行性的数据库一致性保证技术;（2）采用替代的正确性准则，放宽了对可串行性和原子性的要求。 试点系统开发的串行化和宽松的串行化模型进行性能评估，以确定开发的计划允许高度的并发性。 研究结果将为开发一个完整的多数据库管理系统提供基本的事务管理机制。 ***

9221301 Silberschatz Transaction Management in a Heterogeneous Database Environment This is the first year of a three-year continuing award. A multidatabase system (MDBS) consists of a number of sites which run distinct commercial database management systems (DBMSs). The goal of an MDBS is to integrate the DBMSs, allowing applications to access data from, without requiring modifications to, the individual DBMSs. The autonomous user organizations in a multidatabase system generally have invested substantial capital in the DBMS and may, rightly, be unwilling to modify or lose control over their DBMSs. Therefore, it is imperative to develop multidatabase transaction processing methods that allow a high degree of local autonomy, but support users' data in a consistent and reliable manner. This research investigates how to manage and guarantee consistency of data residing in heterogeneous DBMSs, while adhering to the autonomy requirements of the participant DBMSs. The MDBS transaction management schemes developed in this research have the following characteristics: (1) adapt to MDBS environments, existing techniques for ensuring database consistency based on preserving transaction atomicity and serializability; (2) utilize alternate correctness criteria that relax the serializability and atomicity requirements. Pilot systems developed for both the serializability and the relaxed serializability models are used to conduct performance evaluation to ascertain that the developed schemes permit a high degree of concurrency. The results of the research will provide the basic transaction management mechanisms necessary for the development of a complete multidatabase management system. ***