Edge Case Handling and Debugging Questions

Covers the systematic identification, analysis, and mitigation of edge cases and failures across code and user flows. Topics include methodically enumerating boundary conditions and unusual inputs such as empty inputs, single elements, large inputs, duplicates, negative numbers, integer overflow, circular structures, and null values; writing defensive code with input validation, null checks, and guard clauses; designing and handling error states including network timeouts, permission denials, and form validation failures; creating clear actionable error messages and informative empty states for users; methodical debugging techniques to trace logic errors, reproduce failing cases, and fix root causes; and testing strategies to validate robustness before submission. Also includes communicating edge case reasoning to interviewers and demonstrating a structured troubleshooting process.

MediumTechnical

0 practiced

Design a test harness that lets you inject faults into your daily ETL: simulate network latency, permission denials, disk full, and downstream quota errors. Describe orchestration, fault injection mechanisms, assertions for expected behavior (retries, graceful degradation), safety guards, and how to integrate into CI/CD.

EasyTechnical

0 practiced

How do you document known edge cases, validation rules, and assumptions for data pipelines so downstream consumers understand expected behavior? Describe repository organization, schema docs, sample bad-good datasets, automated tests that keep docs current, and how to expose this in a data catalog.

EasyTechnical

0 practiced

Design examples of clear, actionable error messages and empty-state screens/messages for a data warehouse ingestion UI and a REST API. Provide templates for transient errors (network timeout), permanent errors (permission denied), and empty-data states (no results). Also explain what to include in logs for engineers vs what to display to end users.

MediumTechnical

0 practiced

Implement a retry strategy for database writes used by your ETL job. Provide pseudocode that demonstrates exponential backoff with jitter, a max retry limit, and integration with idempotent upsert logic (e.g., using a unique key or upsert statement). Discuss when to abort and how to surface failures.

MediumTechnical

0 practiced

Design and describe a high-throughput deduplication approach for a streaming event pipeline using Bloom filters. Outline how you would size the Bloom filter, manage false positives, rotate or persist filter state across windows/partitions, and what consequences false positives would have for downstream analytics.

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