Triage
- If product pages and checkout are both slow on web, while checkout's own handling time and payments are normal, the time is spent in web or on the host.
- Intermittent slowness on a fraction of requests with no change in error rate is often host contention (CPU steal, a noisy neighbour, swap) or the network. Check host metrics and whether other services on the host show the same pattern.
- A web release that went out long before the slowness started is unlikely to be the cause. Correlation in time, and slow code in the changed paths, are both needed.
Mitigation
There is no safe one-click fix for host-level slowness. Gather more data, and escalate to the platform team if it lasts more than 15 minutes.