Database-Level Caching with Materialized Views and Summary Tables: The Art of Precomputed Truth

Let me rewind to a Tuesday afternoon I’d rather forget. We had a Rails monolith that had grown fat and happy over five years. The dashboard—a beautiful, chart-filled monster—was running a 12-second query every time the CEO clicked “refresh.” Twelve seconds of GROUP BY , COUNT(DISTINCT) , and LEFT JOIN hell across a million-row events table. The CEO didn’t yell. He just stared at the spinning cursor and said, “This used to be fast.” That silence was worse. I’d already tried everything. Redis cach