基于ARC的闪存数据库缓冲区算法

Buffer Replacement Algorithm for Flash-Based Databases Based on ARC

闪存是一种纯电子设备,具备体积小、数据读取速度快、能耗低、抗震性强等优点,被用来部分替代机械硬盘从而提升存储系统的性能.但是,现有的缓冲区置换算法都是针对机械硬盘的物理特性进行设计和优化,因此有必要针对闪存的物理特性重新设计缓冲区置换算法.提出一种新的面向闪存数据库的缓冲区替换算法CF-ARC.算法设计了一种新的页替换机制,即在替换干净页或者脏页的时候考虑其访问频度的大小,优先将访问频度少的干净页替换出缓冲区,使得热页继续留在缓冲区提高命中率,从而获得更好的性能,通过对实验结果的对比分析发现CF-ARC在多数情况下具有比其它置换算法更高的性能.

Flash memory is a pure electronic equipment and has the advantages of smaller volume,faster reading speed,lower power consumption and strong vibration resistance,so it is used to partly replace the disk to improve the performance of storage system.But the existing design and optimization of buffer replacement algorithms are based on the physical characteristics of mechanical hard disk.Therefore,it is necessary to redesign a new buffer replacement algorithm which contrapose the physical characteristics of flash memory.This study presents a new buffer replacement algorithm named CF-ARC.A new type of page mechanism replacement is designed,which means the access frequency should be considered when the clean or dirty pages are replaced.The clean pages less visit should replace the buffer to improve the hit rate in hotspot and achieve a better performance.The experimental results show that CF-ARC has better performance than other buffer replacement algorithms in most cases.