Latency regression detection is a change point detection problem

For latency optimization efforts — where every 5–10 ms improvement matters — it’s important not to give those gains back to regressions. Detecting such regressions, however, is harder than it seems. Latency distributions are typically long-tailed and volatile, making it difficult to notice when something like an additional SQL round-trip quietly adds 3 ms to request latency. A natural approach is…