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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. CDC Pipeline Design intermediate

    You are sizing the Kafka topic behind a CDC pipeline. The source Postgres takes about 12 million row changes a day across 40 tables, the average row is about 1.2 KB, the connector emits before and after images plus metadata, and the platform team wants 7 days of retention so a failed consumer can be rebuilt without a new snapshot. Roughly how much broker storage, and which assumption dominates the error?

    3 min answer cdckafkacapacity planningretention
  2. Data Platform Architecture advanced

    A mobility platform's data team is overwhelmed by requests and every new dataset requires their involvement. What is the structural problem?

    2 min answer data-platformself-serviceownershipbottleneck
  3. Data Platform Architecture advanced

    You are the first data platform engineer at a 200-person company. The CFO's board pack is assembled in a spreadsheet from three CSV exports, the product team queries a read replica directly, and two teams have started separate warehouse trials. Your manager asks what you will do in the first quarter. Walk me through how you would answer.

    2 min answer interviewplatformprioritisationstakeholders
  4. Data Platform Tenancy advanced

    A data platform serves many internal teams with very different data volumes and sensitivity. How should tenancy be structured?

    2 min answer data-tenancyisolationaccess-controlcost
  5. Data Platform Tenancy advanced

    A departing tenant's contract requires deletion within 30 days. Their rows sit in a shared 40 TB events table in an open table format - partitioned by event_date with tenant_id as one column of 60, snapshot retention 90 days, compaction weekly. An engineer runs a DELETE for that tenant_id. What happens next, and what is the 30-day clock actually measuring?

    3 min answer datadogtenancydeletionretention
  6. 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
  7. 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
  8. 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
  9. 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
  10. 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
  11. 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
  12. 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