Microsoft Data Engineer Interview Questions

I would explain the business goal, the data sources, the transformations, and the validation steps I added. A strong answer shows that I understand reliability, observability, and how the pipeline supports real decisions rather than just moving data around.

I would split the pipeline into ingestion, validation, transformation, and serving stages so each part can be monitored and scaled independently. I would also design for idempotency, backfills, and failure recovery so reruns do not corrupt downstream data.

I would define a stable deduplication key and apply it consistently before aggregation or loading. If the source is at-least-once, duplicates are expected, so the pipeline should remove them explicitly rather than relying on luck.

I would identify whether the delay comes from source ingestion, transformation, shuffle, or sink writes. Then I would inspect recent volume changes, resource pressure, skew, and upstream dependency changes to find the bottleneck instead of guessing.

I would partition the data by a stable time or business key and make transformations deterministic so a historical window can be recomputed safely. Incremental loads handle freshness, while backfills let me repair or rebuild a time range without breaking current outputs.