# Logistics company Canonical URL: Domain: Pipeline Design ยท Difficulty: medium ## Problem Logistics company. 400 nightly pipelines accumulated over four years. Finance asks for a corrected Q1 revenue figure after a billing-system migration; the audit found duplicates in three of the last 90 partitions of two facts and a customer dimension. 10-Q files in two weeks. Apply the section's five-step synthesis so the affected facts and dimension all land on the right idempotency pattern, the orchestrator drives a 60-day backfill, and the dimension MERGE has a uniqueness check. ## Related - [All practice problems](https://datadriven.io/problems) - [Mock interview mode](https://datadriven.io/interview/logistics-company-400-nightly-pipelines-accumulated-over-fo-d720e655) - [System Design Interview Questions](https://datadriven.io/data-engineering-system-design) - [Data Engineering Interview Prep Guide](https://datadriven.io/data-engineer-interview-prep) - [Daily Challenge](https://datadriven.io/daily) --- Source: DataDriven (https://datadriven.io). 100% free data engineering interview prep. Live code execution against Postgres 16, Python 3.11, and Spark sandboxes. No paywall, no premium tier, no signup gate.