How We Implemented ScyllaDB’s “Tablets” Data Distribution

ScyllaDB has introduced a new tablets architecture to enhance its data distribution capabilities, enabling dynamic scaling and improved performance. Tablets serve as the smallest replication unit in ScyllaDB, allowing for autonomous and flexible data balancing, which ensures even sharding and replication across the cluster to optimize performance. The implementation involves a tablets table that stores metadata and facilitates a shift from static to dynamic data distribution, with the synchronization of nodes managed via Raft. This architecture includes independent tablet units that allow for efficient data migration and a load balancer that manages tablet transitions to maintain optimal node utilization without human intervention. Additionally, new tablet-aware drivers have been developed to enhance performance and reduce latency, although they do not scan the tablets table directly to avoid inefficiencies. This new approach is designed to make ScyllaDB more elastic, with plans for further innovations in future versions.