Code RoomCheckout latency spikes
HardPrep Room Coding #2618

Checkout latency spikes

On-callCode quality & reviewSenior–Staff~35 min

A non-critical 'related recommendations' enrichment dependency degraded to ~10s response times (it's slow, not down). Within minutes your primary checkout API — which only calls recommendations as an optional sidebar enrichment — saw its own p99 climb to 10s, threads pile up, and it starts failing health checks and getting killed/restarted, taking down checkout entirely. The recommendations call has no explicit timeout and is made inline in the request path. How do you triage and mitigate?

What a strong answer looks like

Stop the bleeding first (mitigate), then form hypotheses from real signals. Separate root cause from symptom, communicate status as you go, and close with what prevents a repeat.

0:00 of about 35 min
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.