Abstract

Storage management is important to the performance of DBMS. This paper gives a comprehensive overview of storage management in relational DBMS. The storage management is divided into three levels (logical, physical in-memory, and physical on-disk) and discussed separately. The logical level caches logical units (tuples or index values) of the DBMS based on the logical information to improve buffer pool usage efficiency. The physical in-memory level caches physical pages directly in the buffer pool to reduce disk accesses. Many algorithms have been designed for the general buffer or for the buffer pool of DBMS. Complex algorithms can achieve better performance than simple LRU or CLOCK algorithms. However, the overhead is high and the advantage diminishes when the buffer is big. The physical on-disk level borrows many techniques from file systems and storage systems. Because of the excellent potential write performance of log-structured organization, the Log-structured File System and related topics are discussed. Each level has its advantage and limitation for further improving performance. To achieve better performance of storage management systems of DBMS, all these three levels should be considered. 1

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