Reviewed by Aditya Kumar · Last reviewed 2026-03-24
BigQuery Cache stores query results for repeat queries. If you run the same query (or one that matches cached byte ranges) within 24 hours, BQ returns cached results without scanning data—no charge for bytes scanned. Caching applies to table metadata and query results. Best...
This easy-level SQL question appears frequently in data engineering interviews at companies like EY. While less common, it tests deeper understanding that distinguishes strong candidates. Mastering the underlying concepts (bigquery) will help you answer variations of this question confidently.
Start by clearly defining the core concept being asked about. Interviewers want to see that you understand the fundamentals before diving into implementation details. Structure your answer with a definition, then explain the practical application with a concise example.
BigQuery Cache stores query results for repeat queries. If you run the same query (or one that matches cached byte ranges) within 24 hours, BQ returns cached results without scanning data—no charge for bytes scanned. Caching applies to table metadata and query results. Best practice: Use consistent query patterns (same filters, no randomness) to hit cache. Parameterized queries can cache when parameters match. For dashboards, design queries to be cache-friendly. Note: DML changes invalidate relevant cache. Use cache for development and repeated reports. Why it matters: Design choices compound at scale—wrong approach can cause 100× overhead. Scalability trade-offs: Profile before optimizing; validate on sample then full. Cost implications: Suboptimal choices multiply at billion-row scale.
Red Flag: Generic textbook answers. Pro-Move: 'At scale we measured X, implemented Y, achieved Z%—validated and iterated.'
Some links below are affiliate links. If you buy through them we may earn a small commission at no extra cost to you — it helps keep DataEngPrep free.
According to DataEngPrep.tech, this is one of the most frequently asked SQL interview questions, reported at 1 company. DataEngPrep.tech maintains an editor-reviewed database of 1,863 data engineering interview questions across 7 categories.