Reviewed by Aditya Kumar · Last reviewed 2026-03-24
**Common issues**: (1) **Pagination**—APIs return partial results; need loop. Use Until activity with Copy/REST call; pass nextToken in request. (2) **Rate limiting**—429 responses. Use retry policy with exponential backoff. (3) **Auth**—OAuth tokens expire. Use Web activity to...
This easy-level Cloud/Tools question appears frequently in data engineering interviews at companies like Virtusa. While less common, it tests deeper understanding that distinguishes strong candidates.
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.
Common issues: (1) Pagination—APIs return partial results; need loop. Use Until activity with Copy/REST call; pass nextToken in request. (2) Rate limiting—429 responses. Use retry policy with exponential backoff. (3) Auth—OAuth tokens expire. Use Web activity to get token; pass to Copy. (4) Large responses—timeout or memory. Enable pagination; write to staging. (5) Schema drift—columns change. Use schema-less sink or dynamic mapping. Resolution patterns: Until loop for pagination; retry with backoff; parameterize auth in linked service. For token refresh, use Web activity + Set variable. Scalability: High request volume can hit API limits—batch or use bulk endpoints. Cost: REST Copy uses IR; many small calls = more IR time. Best practice: Document API behavior; handle 429/401 in retry; validate response shape.
Pro-Move: 'We built a pagination pattern with Until + variable for nextToken—reusable across 10 REST sources; reduced custom code 80%.' Red Flag: No retry policy or assuming APIs don't paginate—production APIs always do.
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According to DataEngPrep.tech, this is one of the most frequently asked Cloud/Tools interview questions, reported at 1 company. DataEngPrep.tech maintains an editor-reviewed database of 1,863 data engineering interview questions across 7 categories.