HDC: An adaptive buffer replacement algorithm for NAND flash memory-based databases

This paper proposes an adaptive buffer replacement algorithm for NAND flash memory-based databases, which is called HDC. HDC introduces an efficient replacing index for selecting pages to be evicted. This replacing index considers two factors: the hot degree of each page and the cost of writing the victim page back to NAND flash memory. It can adaptively change the weight of each factor according to the cost ratio of NAND flash memory. HDC also introduces an efficient partial update scheme, which only writes the dirty data within the dirty victim page back to NAND flash memory for further reducing the number of write operations and writes the dirty data to the free block with the lowest erase count for improving the wear-leveling degree of NAND flash memory. We conduct trace-driven simulations on two kinds of NAND flash memories the cost ratios of which are 118:1 and 2:1. The experimental results show that HDC outperforms the state-of-the-art algorithms on both these kinds of NAND flash memories.