Production Support and Incident Response

1. Detection — something is noticed as broken, either by monitoring (Module 39's stuck-transaction query is a real example) or a user report.
2. Triage — assessing severity: how many users are affected, is data at risk, does this need to be fixed immediately or can it wait?
3. Resolution — actually fixing the issue, often using Lesson 4's production-debugging techniques, then deploying the fix (Module 40, Lesson 5's release discipline).
4. Follow-up — a brief written summary of what happened and why, so the same issue is less likely to recur.

# Incident Summary: Payment Processing Delays

**What happened:** Between 14:00-14:45, ProcessPaymentJob failed
for ~40 orders due to the payment gateway's API timing out.

**Impact:** 40 orders stuck at "Ready for Payment" status; no
charges were incorrectly processed (Module 39's decline/error
distinction correctly classified these as retryable errors).

**Resolution:** The gateway's outage resolved itself; Module 39's
automatic retry logic (up to 3 attempts) successfully processed
all 40 orders without manual intervention once the gateway
recovered.

**Follow-up:** No code change needed — this incident is a real-
world confirmation that Module 39's retry design worked exactly as
intended.

This mirrors Module 39's own project structure directly — the retry logic built and tested there is exactly what turned a real gateway outage into a non-event requiring no manual fix at all.

Incident response draws on nearly everything this module and Module 33 have covered: Lesson 4's production debugging, Lesson 5's rollback readiness, and — as the example above shows — genuinely well-designed features (like Module 39's retry logic) can turn what would otherwise be a serious incident into a routine, self-healing event. Professional engineering practice isn't only about writing correct code — it's building systems resilient enough that things going wrong doesn't automatically mean a crisis.