HyBuffer: A Distributed Hybrid Shared Buffer for Multi-master Databases

Distributed shared buffer (DSB) is a well-known solution to support multi-master database systems. DSB involves controlling access to shared data among different nodes through lock-based cache coherence protocols. However, existing DSB implementations resolve conflicts at the page level, lacking the flexibility required by modern cloud database systems. In this paper, we present HyBuffer which integrates both rows and pages within the DSB framework. It enables multiple masters to independently modify different rows on the same page, thereby enhancing concurrency and performance without altering the disk-based storage structure. Optimized hybrid row and page buffers offer concurrent access to multiple versions in memory while facilitating the asynchronous consolidation of modified rows into their remote page owners. The optimized log subsystem in HyBuffer enables efficient detection of log flushing dependencies among masters, ensuring fast transaction committing. Experiments demonstrate that HyBuffer achieves better scalability and performance compared to existing approaches.