Real-Time Metrics Dashboards with SQL: Patterns That Actually Scale (opens in new tab)

You ship a SaaS app. A customer asks for a dashboard. "Just show us live numbers," they say. Easy. Three weeks later, your SELECT COUNT(*) FROM events WHERE created_at > now() - interval '24 hours' query is taking eight seconds, your database CPU is pegged, and every dashboard auto-refresh slows down the rest of the app. Sound familiar? Real-time metrics dashboards look trivial on the product roadmap and turn into a swamp the moment real data shows up. The good news: most of the hard parts ha...