計算 p50、p95 和 p99 API 延遲

SELECT
  route_template,
  COUNT(*) AS requests,
  approx_percentile_cont(latency_ms, 0.50) AS p50_ms,
  approx_percentile_cont(latency_ms, 0.95) AS p95_ms,
  approx_percentile_cont(latency_ms, 0.99) AS p99_ms
FROM api_requests
WHERE timestamp_utc >= now() - INTERVAL '24 hours'
  AND status_code < 500
GROUP BY route_template
HAVING COUNT(*) >= 50
ORDER BY p95_ms DESC
LIMIT 10;