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2707 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 areas2707 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 Architecture96 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 Architecture98 Streaming & Real-Time Data93 Data Governance & Semantics91 Frontend & Experience Architecture91 Edge, Mobile & IoT88 Regulatory & Data Protection Architecture90 Assurance, Audit & Model Risk98
Difficulty Any beginner intermediate advanced

51 questions in Data Platform Architecture.

  1. Data Platform Tenancy advanced

    A product-analytics platform serves many customers' data on shared infrastructure. What isolation is required at the storage and query layers?

    2 min answer posthogtenancyisolationquotas
  2. Data Platform Tenancy advanced

    Pinterest described in 2015 how every object it stores carries a 64-bit identifier with the shard number packed into the high bits, so any object routes to its database without a lookup. Your analytics platform holds 40 TB of event tables for 900 internal tenants keyed by a random UUID, and an engineer proposes adopting the same trick for the warehouse. What does packing the tenant into the key actually buy on the analytical side, and where would copying Pinterest be a mistake?

    3 min answer pinteresttenancykey designpartitioning
  3. Data Platform Tenancy advanced

    Your multi-tenant analytics platform stores all tenants in shared tables with a `tenant_id` column. What is the risk and how do you close it?

    2 min answer tenancysecurityisolation
  4. Data Vault Modelling advanced

    A bank implemented Data Vault for auditability. Analysts say it is unusable and are extracting to spreadsheets. What went wrong?

    2 min answer modellingconsumptiongovernance
  5. Data Vault Modelling advanced

    A team proposes Data Vault for a customer domain. The source is one table of 40 columns, of which 6 are business or foreign keys and 34 are descriptive attributes changing at three clearly different rates. Before agreeing, estimate how many physical tables the vault produces, how many joins a plain "current customer with address and account status" query needs, and how many rows five years of history holds for 8 million customers. Which assumption dominates the error?

    3 min answer data vaultestimationsatellitesjoin depth
  6. Data Vault Modelling advanced

    An interviewer says - a regulator can ask us what any published report said on any date in the past two years and why it said that. Our platform already has a Data Vault. Where do you take this?

    3 min answer data-vaultreproducibilitybitemporalaudit
  7. Data Vault Modelling advanced

    Review this estate. Postgres and three SaaS sources land raw in bronze. A Data Vault of hubs, links and satellites is built in silver. Star schemas are built in gold. Six departmental extracts are then copied into departmental warehouses. Freshness is 40 minutes, the team is six people, and there are 42 dashboards. What would you remove, what would you change, and what would you leave alone?

    2 min answer data-vaultlayeringover-engineeringreview
  8. Data Vault Modelling advanced

    What problem does data vault modelling solve, and when is its complexity justified?

    2 min answer data-vaultauditabilityintegrationcomplexity
  9. Data Virtualisation advanced

    A BI tool queries the operational read replica directly through a federation layer, avoiding a copy. At 09:03 replica lag starts climbing. By 09:12 checkout p99 has tripled. By 09:30 the replica is 40 minutes behind and support is reporting stale order status. What failed, and which design decision allowed it?

    3 min answer federationreplicaspushdownlag
  10. Data Virtualisation advanced

    A vendor proposes replacing your ingestion pipelines with data virtualisation — query everything in place, no copies. Assess it.

    1 min answer federationarchitectureevaluation
  11. Dimensional Modelling advanced

    An interviewer says — design the data model behind a subscription business's revenue reporting. Finance restates prior periods when a contract is amended and the board pack must be reproducible months later. Where do you take this?

    3 min answer bitemporalrestatementgrainfinance
  12. File Formats & Compaction advanced

    A lakehouse table takes 400 GB a day from a streaming job that commits every 60 seconds across 24 partitions. Daily compaction rewrites yesterday's data and a weekly job re-sorts the last 30 days. Roughly how much compute does that maintenance need, what share of the bill is it, and which assumption dominates the error?

    3 min answer compactionmaintenanceplanning-numberscost