An Efficient Buffer Scheme for Flash-based Databases
Most embedded database systems are built on a two-level memory hierarchy, a RAM buffer on top of flash memory. Both kinds of memories have limited capacity, thus, how to efficiently utilize them is critical for embedded systems with resource restrictions. Different from magnetic hard disk, flash memory has speed asymmetry in reads and writes, i.e., random reads are over an order of magnitude faster than random writes. To improve the utilization on the memory resources and the query performance, the authors propose a novel buffer scheme called LRU-N - a Node-based LRU policy for the RAM buffer.