Intuit CS Foundation: Database Pagination Techniques

You’ll be asked to compare and implement pagination strategies across relational and NoSQL databases, focusing on efficiency and real-world scalability.

Core content: You should explain how traditional MySQL pagination using LIMIT/OFFSET works, why OFFSET can be inefficient on large tables, and how window functions like ROW_NUMBER() or keyset (seek) pagination avoid scanning many rows. For DynamoDB, show how query/scan pagination uses LastEvaluatedKey and ExclusiveStartKey, and why cursor-like pagination is the scalable choice for high-throughput workloads.

Flow / stages in an interview: Typically you’ll first describe simple LIMIT/OFFSET behavior and complexity (O(n) skip cost), then propose optimizations (index-anchored keyset pagination, ROW_NUMBER() for stable offsets). Next, map the same requirements to DynamoDB — choose query vs scan, present how to return and consume LastEvaluatedKey, and discuss consistent ordering and partition-key design. Interviewers often ask you to write example SQL and pseudo-code for consuming DynamoDB pages.

Skill signals: Demonstrate practical SQL knowledge (indexes, ORDER BY, window functions), understanding of query planning and complexity, familiarity with NoSQL pagination APIs (DynamoDB LastEvaluatedKey / ExclusiveStartKey), and the ability to reason about trade-offs (latency, memory, consistency, UX of cursors). Prepare concise examples and be ready to discuss pagination with filters, joins, and evolving schemas.