Interview prompt
Problem context
A customer dashboard is served from denormalized views built by streaming events. A schema change requires rebuilding billions of rows while updates continue. Mixing old and new logic produces totals that do not reconcile, and a full downtime window is unacceptable.
Skills being evaluated
snapshot-stream joinsderived-data correctnessversioned publicationvalidation
The full reasoning guide is part of Pro
The scenario and evaluation focus above remain public. Pro unlocks the structured answer, trade-off analysis, follow-up probes, common weak answers, rubric, related reasoning, and any architecture diagram.
Sign in to continueWhat the full guide covers
Clarify the decision
Establish scale assumptions
Functional and non-functional requirements
High-level architecture
Data model and flow
Consistency and transaction boundaries
Failure modes and recovery
Security and privacy
Observability and SLOs
Capacity and cost
Alternatives and trade-offs
Evolution and migration
What Staff and Principal candidates should emphasize