Exploiting Multi-Block Atomic Write in SQLite Transaction

Abstract

This work is dedicated to resolve the journaling overhead of widely used DBMS, SQLite. Database journaling and EXT4 filesystem journaling cause enormous write operations because of the frequent fdatasync() call and Journaling of Journal anomaly between SQLite and EXT4 filesystem. While Write-Ahead-Logging reduces the number of fdatasync() call and write volume, JOJ and database journaling overhead is still remained. In this work, we develop a new SQLite journal mode, MAW mode. We exploit the F2FS filesystem and its Multi-block Atomic Write feature to write updated database pages atomically. MAW mode completely eliminated database journaling and keeps database consistency from unexpected system failure. MAW mode only writes the actually updated database pages, thereby generates smaller write volume. We implement MAW mode at SQLite with most recent version of F2FS. With MAW mode, database insert transaction performance is increased by 487% and write volume is decreased by 67% than stock SQLite PERSIST mode in EXT4 filesystem.