A payments processor must guarantee that refunds and charges are recorded exactly once, support auditors who run cross-customer analysis over several years, and process card authorizations in real time. Which architecture best meets these needs?
Show answer and explanation
Answer: A
A transactional relational database gives strong guarantees for authorizations and refunds in real time, while a separate analytical warehouse handles heavy multi-year queries without slowing payment processing. Splitting these workloads is the standard pattern for combining transactional integrity with analytics. A single document database struggles with ledger-style guarantees, object storage has no transactional writes, and graph databases are not built for this ledger workload.
Why the other options are wrong
- B. A single document database can serve reads quickly, but exactly-once ledger recording across many records is not its strength, and heavy multi-year analysis would contend with live payments.
- C. Object storage keeps files durably but offers no transactional updates across objects, and metadata indexes do not provide ledger consistency for authorizations.
- D. Graph databases excel at traversing relationships such as shared devices or fraud rings. They are not designed for ledger recording or multi-year aggregation of transactions.