SW-WAL: Leveraging Address Remapping of SSDs to Achieve Single-Write Write-Ahead Logging
Qiulin Wua, You Zhoub, Fei Wuc, Ke Wangd, Hao Lve, Jiguang Wanf and Changsheng Xieg
Wuhan National Laboratory for Optoelectronics, Key Laboratory of Information Storage System Engineering Research Center of Data Storage Systems and Technology, Ministry of Education of China School of Computer Science & Technology, Huazhong University of Science & Technology
aqiulin wu@hust.edu.cn
bzhouyou2@hust.edu.cn
cwufei@hust.edu.cn
dwangke25@hust.edu.cn
elvhao@hust.edu.cn
fjgwan@hust.edu.cn
gcs xie@hust.edu.cn
ABSTRACT
Write-ahead logging (WAL) has been widely used to provide transactional atomicity in databases, such as SQLite and MySQL/InnoDB. However, the WAL introduces duplicate writes, where changes are recorded in the WAL file and then written to the database file, called checkpointing writes. On the other hand, NAND flash-based SSDs, which have an inherent indirection software layer, called flash translation layer (FTL), become commonplace in modern storage systems. Innovative SSD designs have been proposed to eliminate the WAL overheads by exploiting the FTL, such as providing an atomic write interface or utilizing its address remapping. However, these designs introduce significant performance overheads of maintaining and persisting extra transactional information to guarantee the transactional atomicity or mapping consistency.
