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Data Lake and Warehouse Architecture Questions

Designing scalable data platforms for analytical and reporting workloads including data lakes, data warehouses, and lakehouse architectures. Key topics include storage formats and layout including columnar file formats such as Parquet and table formats such as Iceberg and Delta Lake, partitioning and compaction strategies, metadata management and cataloging, schema evolution and transactional guarantees for analytical data, and cost and performance trade offs. Cover ingestion patterns for batch and streaming data including change data capture, data transformation approaches and compute engines for analytical queries, partition pruning and predicate pushdown, query optimization and materialized views, data modeling for analytical workloads, retention and tiering, security and access control, data governance and lineage, and integration with business intelligence and real time analytics. Also discuss operational concerns such as monitoring, vacuuming and compaction jobs, metadata scaling, and strategies for minimizing query latency while controlling storage cost.

HardTechnical
59 practiced
Explain how vectorized query execution and columnar caches (e.g., runtime vectorized processing on Parquet column chunks) reduce CPU and IO for analytical queries. Discuss how these engine-level optimizations influence decisions on file size, row-group size, column ordering, and compression choices for datasets powering BI dashboards.
MediumTechnical
67 practiced
Explain Change Data Capture (CDC) approaches relevant to BI: log-based CDC, trigger-based CDC, and file-based incremental pulls. Describe how CDC integrates into a lakehouse for upserts and SCD handling (types 1/2/3), and the implications for downstream dashboards' consistency and deduplication. Mention example technologies (Debezium, Maxwell, cloud-native CDC) and where you'd place merge logic (stream processor vs ELT engine).
MediumTechnical
110 practiced
Describe a retention and tiering strategy for analytics data where recent 90 days must be fast-queryable and older data can be cheaper but still queryable for monthly reports. Include partitioning, lifecycle rules (e.g., S3 storage classes), compaction, and how to design queries or views to transparently access tiered data while keeping storage costs low.
MediumTechnical
69 practiced
Materialized views can speed up BI queries but add maintenance cost. Explain when to use materialized views vs scheduled aggregate tables vs on-the-fly aggregation. Discuss freshness guarantees, incremental maintenance, storage cost, query routing, and failure modes across systems like Snowflake, BigQuery, and Databricks.
HardTechnical
79 practiced
A user requests deletion of their personal data (GDPR). Describe the end-to-end approach to delete or anonymize that user's traces across raw event files, materialized aggregates, nightly summaries, and backups. Highlight technical challenges (e.g., immutable files, SCD-2 dimension history, backups) and verification steps to prove compliance.

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