Database Support For A Three Level Store

传统上，dbms假定所有可访问的数据都驻留在磁盘上，少量数据占用主存缓存中的空间。未来的对象管理器将被要求管理非常大的对象库，其中时间关键型对象永久驻留在主内存中，其他对象驻留在磁盘中，其余的占用第三层内存。此外，可能存在三层以上的存储，其中一些可能存在于偏远的位置。这个项目研究了在单个软件系统中支持多级存储的DBMS的体系结构。该方法是将文件系统、查询优化和抽象数据类型的思想推广并应用于多个存储级别。此外，由于存储可能存在于多个计算机系统上，因此也必须应用分布式数据库的思想。本研究的意义在于解决了超大尺寸的问题。具体来说，新一代dbms正在展开，它将支持比关系dbms处理的业务数据处理应用程序更通用的应用程序。下一个前沿是克服这些新应用带来的巨大尺寸增长。

Traditionally, DBMSs have assumed that all accessible data resides on magnetic disk with small amounts of data occupying space in a main memory cache. Future object managers will be called on to manage very large object bases in which time critical objects resides permanently in main memory, other objects are disk resident, and the remainder occupy tertiary memory. Moreover, there may be more than three levels of storage present, and some of them may exist at remote locations.This project investigates the architecture of a DBMS that can support a multi-level store in a single software system. The approach is to generalize and apply ideas from file systems, query optimization, and abstract data types to multiple levels of storage. In addition, since storage may exist on multiple computer systems, ideas from distributed data bases must also be applied. The significance of this research is that the issue ofmassive size is addressed. Specifically, a new generation of DBMSs is unfolding that will support more general applications than the business data processing ones addressed by relational DBMSs. The next frontier is to overcome the dramatic size increase that these new applications entail.