# A product manager at a retail analytics company asks for a real-time inventory dashboard Canonical URL: Domain: Pipeline Design ยท Difficulty: medium ## Problem A product manager at a retail analytics company asks for a real-time inventory dashboard. The pipeline on the canvas already has the four roles but no slaFreshness labels, and no honest tier conversation has happened. The truth: storefront POS systems batch-export every 15 minutes, the warehouse mart refreshes hourly, and the Looker dashboard auto-refreshes every minute. Apply the five-tier vocabulary this section just taught and translate the real-time request into the concrete tier the chain can actually deliver. Tag each node with a slaFreshness value consistent with the slowest upstream hop: the POS source is < 15min (Tier 2), the ingest job and the warehouse mart cannot beat the 15-min POS rhythm but the warehouse refreshes hourly so it carries < 1h (Tier 3), and the Looker dashboard inherits the warehouse's tier (< 1h or < 2h). No node may carry a real-time or < 1min label, because the upstream cannot back it. ## Related - [All practice problems](https://datadriven.io/problems) - [Mock interview mode](https://datadriven.io/interview/a-product-manager-at-a-retail-analytics-company-asks-for-a-r-b19d94a5) - [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.