Journaling of journal is (almost) free

• DOI: 10.5555/2591305.2591333
• Publication Date: 2014-02-17
• Authors: Kai Shen; Stan Park; Meng Zhu

Lightweight databases and key-value stores manage the consistency reliability of their own data, often through rollback-recovery journaling or write-ahead logging. They further rely on file system to protect structure metadata. Such journal appears violate classic end-to-end argument for optimal database design. In practice, we observe a significant cost (up 73% slowdown) by adding Ext4 SQLite Google Nexus 7 tablet running Ubuntu Linux installation. The is up 58% conventional machine with an Intel 311 SSD.In this paper, argue that such largely due implementation limitations existing system. We apply two simple techniques--ensuring single I/O operation synchronous commit path, adaptively allowing each have custom mode (in particular, whether data in addition metadata). Compared without journaling, our enhanced improves performance incurs minor (