Online retail: preparing for campaigns and traffic peaks.
A scenario for retailers whose campaigns rely on catalog, search, checkout and payments.
Business context
A campaign concentrates visits, searches and orders into a short window. Serving the homepage is only one concern: catalog, delivery calculation and payment depend on several services.
Risks we assess
Unbounded queries, simultaneous cache invalidation, PHP workers exhausting memory, delayed queues and payment retries that duplicate operations. We also examine behavior when an external integration slows down.
Intervention plan
Establish a baseline from current traffic and resources. Identify critical routes and measure latency, errors and saturation. Tune queries, indexes, worker limits, cache and timeouts. Run a bounded load test in an authorized environment and rehearse rollback before the campaign.
Deliverables
Checkout dependency map; bottleneck report; prioritized changes with owners; load-test report; campaign checklist and a runbook for external-service degradation.
How we validate
Compare p95/p99 latency and critical-route errors under the same workload before and after changes. Agree the test volume and verify order integrity. Capacity is validated per environment; this scenario does not claim sales figures or achieved improvements.