# Two years of event history sits in one hot warehouse table

Canonical URL: <https://datadriven.io/problems/two-years-of-event-history-sits-in-one-hot-warehouse-table-67ba2051>

Domain: Pipeline Design · Difficulty: medium

## Problem

Two years of event history sits in one hot warehouse table. 95% of queries touch the last 30 days, but the team pays hot-storage prices for all of it. Design tiered storage that keeps recent data fast and old data cheap, still queryable.

## Related

- [All practice problems](https://datadriven.io/problems)
- [Mock interview mode](https://datadriven.io/interview/two-years-of-event-history-sits-in-one-hot-warehouse-table-67ba2051)
- [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.