Revisiting Page Migration for Main-Memory Database Systems

Modern hardware architectures, e.g., NUMA servers, chiplet processors, tiered and disaggregated memory systems have significantly improved the performance of Main-Memory Databases, and are poised to deliver further improvements in the future. However, realizing this potential depends on the database system's ability to efficiently migrate pages among different NUMA nodes, and/or memory chips as the workload evolves. Modern main memory databases offload the migration procedure to the operating system without accounting for the workload and its migration characteristics. In this paper, we propose a custom system call move_pages2 as an alternate to Linux's own move_pages system call. In contrast to the original move_pages, move_pages2 allows partial migration and exposes two configuration knobs, enabling a Main-Memory Database tailor the migration process to its specific requirements. Experiments on a main-memory B$^+$-Tree for a YCSB-like workload show that the proposed move_pages2 custom system call improves the B$^+$-Tree query throughput by up to 2.3$\times$, and migrates up to 2.6$\times$ more memory pages, outperforming the native Linux system call.