# An operational SLA states 'fresh by 6am'; a quality SLA states 'correct row counts and null rates by Canonical URL: Domain: Pipeline Design ยท Difficulty: medium ## Problem An operational SLA states 'fresh by 6am'; a quality SLA states 'correct row counts and null rates by 6am.' The two are independent: a pipeline can meet 6am with a 30 percent row-count drop, or have flawless data and miss 6am. Status pages that report a single number describe operational SLA exclusively, leaving consumers unable to distinguish 'late but correct' from 'on time but wrong.' Split the SLAs by adding two separate monitoring paths off the curated table, one whose name states the operational SLA target and the orchestrator metric it reads, and one whose name states the quality SLA target and the gates it depends on. Each path routes to its own paging destination. ## Related - [All practice problems](https://datadriven.io/problems) - [Mock interview mode](https://datadriven.io/interview/an-operational-sla-states-fresh-by-6am-a-quality-sla-stat-25746aff) - [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.