A freshness SLA is a promise about how up to date a dataset will be. Example: "fct_orders is no more than 2 hours behind source by 9am local on weekdays."
SLA: max delay 2 hours source max time: 07:00 warehouse max time: 10:30 -> BREACH
How platforms enforce it
- Track
max(event_time)or load timestamps - Alert when age exceeds threshold
- Page owners when executive dashboards break SLA
- Separate warn vs critical thresholds
Design note
SLAs should match business need. Fraud alerting may need minutes; monthly finance close may tolerate a day.
Interview tip: Define SLA as a measurable freshness target, then mention monitoring max(loaded_at) and owner escalation.