Quiz

2667 questions of the kind that actually get asked — in interviews, in architecture review boards, and by the person who has to run the thing at 3 AM. Every answer states the trade-off rather than the slogan, and says when the obvious choice is the wrong one.

All areas2667 Architecture Fundamentals81 Distributed Systems101 Data Architecture90 Cloud Architecture87 Networking86 API & Integration Architecture78 Reliability & Resilience88 Observability81 Performance & Capacity Engineering90 Security Architecture95 Cost Architecture & FinOps92 Business Architecture93 Architecture Communication91 Enterprise Architecture91 Legacy Modernization92 AI-Era Architecture86 Software Architecture & Engineering84 Architecture Patterns84 Architecture Decision-Making91 The Architect's Meta-Skills92 Delivery & Release Engineering93 Platform Engineering & Developer Experience92 Testing & Quality Architecture90 Data Platform Architecture88 Streaming & Real-Time Data93 Data Governance & Semantics81 Frontend & Experience Architecture91 Edge, Mobile & IoT88 Regulatory & Data Protection Architecture90 Assurance, Audit & Model Risk88

Difficulty Any beginner intermediate advanced

60 questions in Data Architecture.

Quiz

Four services want four different databases: Postgres, MongoDB, Cassandra and Neo4j. What do you say?

Your search index and your database disagree — some products appear in search that were deleted, and some new ones never appear. How do you make this reliable?

A query that ran in 50ms for two years now takes 90 seconds. Nothing was deployed and the data volume grew normally. What happened?

In a multi-tenant platform where every tenant's data shares the same physical tables and tenants differ in size by orders of magnitude, why do query plans that are optimal for one tenant become pathological for another - and what is the fix?

An issue-tracking product lets every customer define custom fields, workflows and screens. Which data model should the platform use for custom fields?

Users report seeing stale data intermittently. Replication lag is normally under a second but spikes to minutes twice a day. How do you handle it?

A live-streaming platform must compute real-time viewer counts, chat rate and moderation signals during events where concurrent viewers spike tenfold within minutes. What streaming architecture handles this, and what happens if the stream processor falls behind?

A streaming aggregation reports lower totals than the batch job it replaced. Both read the same source. What is likely happening?

A streaming aggregation stops emitting results. The job is healthy, consuming messages and using CPU. What is the most likely cause?

A fashion marketplace lets sellers update inventory while customers are checking out. How should reservations, optimistic concurrency, expiry, retries and failed payments interact to prevent overselling?

A financial application runs at read-committed isolation. Two concurrent transactions each read an account balance, check it is sufficient, and debit it. Both succeed and the account goes negative. What happened, and which fixes are correct?

A rule requires at least one engineer on call. Two engineers simultaneously remove themselves; both transactions check the rule, both pass, both commit. Nobody is on call. Name the anomaly and three fixes.