A Write-Optimized B-Tree Layer for NAND Flash Memory

For B-tree index structure which requires intensively fine-grained updates/modifications, directly implementing this index structure over flash memory could lead to a significant number of write operations. In this paper, a write-optimized B-tree layer is proposed called WOBF which works over FTL in the flash memory. It could not only reduce the number of write operations by buffering index units in the index buffer and handling them in a batch, but also eliminate the number of pages used to store the index units reflecting the modified node. The performance benefits are proven theoretically and validated empirically.