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Shazan Ansar
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Engineering, Personal project

Near real-time lakehouse

A medallion lakehouse with schema enforcement and quality gates, built so analytics and ML read from fresh, trustworthy tables.

Role
Designed and built
Stack
Python, SQL, PySpark, Delta Lake, Airflow, S3
  1. Raw ingestion (bronze)
  2. Clean and dedupe (silver)
  3. Quality gate
  4. Business and feature tables (gold)
Layers
Bronze, silver, gold
Promotion rule
Quality gate

Problem

Analytics and ML both depend on data that is fresh and correct. Pipelines that silently pass bad records, or that break when a schema changes, erode trust in every dashboard and model downstream.

Architecture

  • Bronze: raw ingestion with the incoming schema captured as-is.
  • Silver: cleaned, standardised, and deduplicated records.
  • Gold: business-ready tables and feature-ready tables for models.

Engineering decisions

  • Schema evolution rules so new columns don't break downstream jobs.
  • Late-arriving data handled explicitly rather than dropped.
  • Quality gates (null, uniqueness, and range checks) that must pass before data is promoted to the next layer.
  • Partitioning chosen for the dominant query patterns.

Outcome

Fresher tables for analytics, fewer downstream pipeline failures, and feature tables that shorten ML experiment set-up.

What I'd improve

  • Data contracts with producers instead of defensive checks alone.
  • Lineage tracking so a bad gold row can be traced to its source.
Next projectRAG analytics assistant