Redesigning a Tangled Graph

Concepts covered: paArchitectureRedesign

The synthesis exercise is a real-shaped problem. A mid-size company has accumulated 80 production DAGs over four years. The data team has grown from three engineers to twelve. The new tech lead has been asked to make the system operable. The exercise walks through the diagnosis and the redesign, using every concept from the lesson and the prior tiers. The Symptoms Diagnosis: What Each Symptom Reveals Redesign Step 1: Establish the Layered Shape The first move is to introduce a shared raw layer and a shared curated layer if they do not already exist in clean form. Audit every existing DAG. Each one becomes a candidate for relocation: the parts that read sources move into a shared raw landing layer, the parts that produce business-ready tables move into a shared curated layer, and the parts

About This Interactive Section

This section is part of the What a Data Pipeline Is: Advanced lesson on DataDriven, a free data engineering interview prep platform. Each section includes explanations, worked examples, and hands-on code challenges that execute in real time. SQL queries run against a live PostgreSQL database. Python runs in a sandboxed Docker container. Data modeling problems validate against interactive schema canvases. All content is framed around what data engineering interviewers actually test at companies like Meta, Google, Amazon, Netflix, Stripe, and Databricks.

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DataDriven combines four interview rounds (SQL, Python, Data Modeling, Pipeline Architecture) with adaptive difficulty and spaced repetition. Easy problems get harder as you improve. Weak concepts resurface until you master them. Your readiness score tracks progress across every topic interviewers test. Every lesson section ends with problems you solve by writing and running real code, not by picking multiple-choice answers.