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Quiz

2777 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 areas2777 Architecture Fundamentals81 Distributed Systems101 Data Architecture90 Cloud Architecture87 Networking86 API & Integration Architecture87 Reliability & Resilience99 Observability92 Performance & Capacity Engineering90 Security Architecture95 Cost Architecture & FinOps92 Business Architecture93 Architecture Communication91 Enterprise Architecture100 Legacy Modernization92 AI-Era Architecture96 Software Architecture & Engineering93 Architecture Patterns84 Architecture Decision-Making91 The Architect's Meta-Skills92 Delivery & Release Engineering93 Platform Engineering & Developer Experience92 Testing & Quality Architecture102 Data Platform Architecture98 Streaming & Real-Time Data93 Data Governance & Semantics91 Frontend & Experience Architecture91 Edge, Mobile & IoT88 Regulatory & Data Protection Architecture99 Assurance, Audit & Model Risk98
Difficulty Any beginner intermediate advanced

98 questions in Data Platform Architecture.

  1. Data Vault Modelling advanced

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

    2 min answer data-vaultauditabilityintegrationcomplexity
  2. 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
  3. Data Virtualisation intermediate

    A federation layer serves 60 analysts across four sources: the lakehouse, a Postgres replica, a managed warehouse and a SaaS REST connector. At 11:40 the REST connector's upstream begins answering in 40 seconds rather than 200 ms. Nothing errors and nothing is down. Walk through what happens to the other analysts over the next ten minutes.

    3 min answer federationhead-of-line blockingbulkheadsconcurrency
  4. Data Virtualisation intermediate

    A group holds customer data in separate EU and US entities, and the rows may not be copied across the border. The board wants one revenue dashboard. The team puts a federation layer over both regions and queries in place rather than consolidating. What has that bought, when does the bill arrive, and how do they keep the option to reverse it?

    2 min answer federationresidencypushdowncross-region
  5. Data Virtualisation intermediate

    A platform proposes querying operational databases directly rather than copying data. When does that work?

    2 min answer virtualisationfederationcouplingload
  6. 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
  7. Dimensional Modelling intermediate Multiple choice

    A BI team replaces a 9-table star schema with a single denormalised table of 240 columns because dashboards were slow and analysts kept joining at the wrong grain. Six months later the table is 4 TB across roughly 3 billion rows, the nightly build takes 5 hours, and correcting one product's category requires a full rebuild. Which property did the flattening actually trade away?

    3 min answer one big tabledenormalisationscdrebuild cost
  8. 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
  9. Dimensional Modelling beginner Multiple choice

    An order-lines fact table holds 40 million rows per day for three years across 18 columns and is partitioned by order date. In Parquet it averages roughly 36 bytes per row compressed and columns are of similar width. A dashboard query reads three columns over the last 90 days. Roughly how many bytes does it scan?

    2 min answer estimationcolumnarpartition-pruningstar-schema
  10. Dimensional Modelling intermediate

    When is dimensional modelling still the right approach, and what does it cost?

    2 min answer dimensional-modellingstar-schemausabilityperformance
  11. 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
  12. File Formats & Compaction intermediate

    A lakehouse team raises its compaction target file size from 128 MB to 1 GB and switches the write codec from Snappy to Zstandard. Query cost falls. What did they give up, and when does that bill arrive?

    2 min answer datadogcompactionparquetzstd