4.3. Optimize Performance

💡 First Principle: Performance optimization balances resource consumption against query latency—like tuning an engine for either fuel efficiency or speed. The goal is achieving acceptable performance at minimum cost, not maximum performance at any cost.

What breaks without optimization? A Delta table that received millions of small writes from streaming ingestion. Queries that once took 10 seconds now take 5 minutes because Spark must open thousands of small files. Without regular optimization, performance degrades until the system becomes unusable.