Dynamic in-page logging for flash-aware B-tree index

Abstract

This paper presents Dynamic IPL B+-tree (d-IPL in short) as a B+-tree index variant for flash-based storage systems. The d-IPL B+-tree adopts a dynamic In-Page Logging (IPL) scheme in order to address a few new problems that are caused by the unique characteristics of B+-tree indexes The d-IPL B+-tree avoids the frequent log overflow problem by allocating a log area in a flash block dynamically. It also addresses elegantly the problem of page evaporation, imposed by the contemporary NAND flash chips, by introducing ghost nodes within the context of the dynamic IPL scheme. This simple but elegant design of the d-IPL B+-tree improves the performance significantly. For a random insertion workload, the d-IPL B+-tree index outperformed a B+-tree with a plain IPL scheme by more than a factor of two in terms of page write and block erase operations. Copyright 2009 ACM.