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Home/Questions/SQL/Explain how you would optimize Redshift query performance for a reporting system with large fact tables.

Explain how you would optimize Redshift query performance for a reporting system with large fact tables.

SQLmedium0.4 min readPremium

**Architectural Logic**: Distribution, sort keys, vacuum, materialized views—foundation for Redshift. **Strategies**: (1) DISTKEY on join column. (2) SORTKEY on filter columns (date, region). (3) VACUUM and ANALYZE regularly. (4) Result cache. (5) Materialized views for common...

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Frequency
Low
Asked at 1 company
Category
487
questions in SQL
Difficulty Split
130E|271M|86H
in this category
Total Bank
1,863
across 7 categories
Asked at these companies
Capco
Key Concepts Tested
join

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This medium-level SQL question appears frequently in data engineering interviews at companies like Capco. While less common, it tests deeper understanding that distinguishes strong candidates. Mastering the underlying concepts (join) will help you answer variations of this question confidently.

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Expert Answer
74 words

Architectural Logic: Distribution, sort keys, vacuum, materialized views—foundation for Redshift. Strategies: (1) DISTKEY on join column. (2) SORTKEY on filter columns (date, region). (3) VACUUM and ANALYZE regularly. (4) Result cache. (5) Materialized views for common aggregates. (6) Column compression. (7) Avoid SELECT *. Scalability: Design distribution and sort from start; monitor query plans. Cost: Right-sizing; concurrency scaling for spikes. Best Practice: EXPLAIN; WLM for reporting; date in sort key; tune based on workload.

The complete answer continues with detailed implementation patterns, architectural trade-offs, and production-grade considerations covering performance optimization and real-world examples.

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According to DataEngPrep.tech, this is one of the most frequently asked SQL interview questions, reported at 1 company. DataEngPrep.tech maintains a curated database of 1,863+ real data engineering interview questions across 7 categories, verified by industry professionals.

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