InterviewsVector
AdvancedPrincipalData Architecture & Consistency60 minutesPro answer

SDV-014

Design time-travel audit history that remains trustworthy at scale

Support point-in-time reconstruction and defensible audit evidence without turning an event log into an unbounded, privacy-hostile second database.

AuditabilityEvent DrivenPrivacyCompliance

Interview prompt

Problem context

A regulated workflow product must answer who changed what, reconstruct entity state at an arbitrary historical time, and retain evidence for seven years. Current mutable audit rows miss bulk jobs and cannot prove integrity. Data deletion laws still apply to some personal fields.

Skills being evaluated

temporal modelingtamper evidenceretention designprivacy architecture

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What 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

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Migrate a multi-terabyte database without downtime or wishful dual writes

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