Main Memory Database Systems: An Overview

Abstract-Memory resident database systems (MMDB’s) store 2) Main memory is normally volatile, while disk storage is their data in main physical memory and provide very high-speed not. However, it is possible (at some cost) to construct access. Conventional database systems are optimized for the particular characteristics of disk storage mechanisms. Memory resident systems, on the other hand, use different optimizations to structure and organize data, as well as to make it reliable. nonvolatile main memory. 3) Disks have a high, fixed cost per access that does not depend on the amount of data that is retrieved during the This paper surveys the major memory residence optimizations access. For this reason, disks are block-oriented storage and briefly discusses some of the memory have been designed or implemented. resident systems that devices. Main memory is not block oriented. 4) The layout of data on a disk is much more critical than Index Terms- Access methods, application programming in-the layout of data in main memory, since sequential terface, commit processing, concurrency control, data clustering, data representation, main memory database system (MMDB), query processing, recovery. access to a disk is faster than random access. Sequential access is not as important in main memories. 5) Main memory is normally directly accessible by the processor(s), while disks are not. This may make data in I