Internals: How PostgreSQL 17's New B-Tree Index vs. MongoDB 8.0's WiredTiger Engine Improves Query Performance in 2026 The 2026 data landscape is defined by unprecedented scale: 80% of enterprises manage datasets exceeding 10PB, with query latency requirements tightening to sub-millisecond for OLTP workloads and sub-second for OLAP. Two technologies lead the charge in index-driven performance: PostgreSQL 17's re-engineered B-Tree indexes, and MongoDB 8.0's upgraded WiredTiger storage engine. This deep dive compares their internals, benchmarks, and real-world optimization strategies.…