Yet Another Write-Optimized DBMS Layer for Flash-based Solid State Storage

摘要

Flash-based Solid State Storage (flashSSS) has write-oriented problems such as low write throughput, and limited lifetime. Especially, flashSSDs have a characteristic vulnerable to random-writes, due to its control logic utilizing parallelism between the flash memory chips. In this paper, we present a write-optimized layer of DBMSs to address the write-oriented problems of flashSSS in on-line transaction processing environments. The layer consists of a write-optimized buffer, a corresponding log space, and an in-memory mapping table, closely associated with a novel logging scheme called Incremental Logging (ICL). The ICL scheme enables DBMSs to reduce page-writes at the least expense of additional page-reads, while replacing random-writes into sequential-writes. Through experiments, our approach demonstrated up-to an order of magnitude performance enhancement in I/O processing time compared to the original DBMS, increasing the longevity of flashSSS by approximately a factor of two.