**Strategy**: (1) Validate at source—schema registry, API validation; (2) Stream validation—Flink/Spark checks (nulls, types, ranges); (3) DLQ—quarantine invalid for triage; (4) Monitoring—alert on DLQ growth; (5) Reprocess from DLQ after fix. Don't block stream; use...
Pro-Move: 'Flink job with side-output for bad records. DLQ to S3; daily report. Reprocess job after schema fix. <0.01% to DLQ.'
This easy-level System Design/Architecture question appears frequently in data engineering interviews at companies like Goldman Sachs. While less common, it tests deeper understanding that distinguishes strong candidates. Mastering the underlying concepts (spark) 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.
Strategy: (1) Validate at source—schema registry, API validation; (2) Stream validation—Flink/Spark checks (nulls, types, ranges); (3) DLQ—quarantine invalid for triage; (4) Monitoring—alert on DLQ growth; (5) Reprocess from DLQ after fix. Don't block stream; use side-outputs; fail fast. Goldman: quality critical for trading.
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Analyze My Answer — FreeAccording to DataEngPrep.tech, this is one of the most frequently asked System Design/Architecture 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.