Inside ScyllaDB’s Continuous Optimizations for Reducing P99 Latency

ScyllaDB's engineering team has been actively working to reduce latency spikes during administrative operations by implementing continuous monitoring and rigorous testing strategies. The team measures operational latency across three workload scenarios—write, read, and mixed—under various conditions such as repairs, node additions, and decommissions, using a detailed methodology that includes preloading data and establishing a baseline latency. Advanced metrics like High Dynamic Range (HDR) Histograms are employed to capture comprehensive latency data, allowing the team to identify performance bottlenecks and make precise optimizations. Recent tests have shown significant improvements, with latencies remaining in the single-digit range, thanks to the introduction of new features in ScyllaDB 6.0, such as tablets for faster cluster resizing and immediate node joining. These ongoing efforts not only enhance the database's performance but also reflect the team's commitment to delivering high-quality solutions that meet user needs.