PostgreSQL Conference Germany 2026

B-trees are the default index type in PostgreSQL and the workhorse behind many query speedups—but developers often use them with only a limited understanding of how they actually work or how to apply them effectively. This talk demystifies B-trees by building them from the ground up and exploring their design, structure, and even a naming history along the way. By emphasizing first principles, we’ll uncover why B-trees perform so well across a wide range of queries and workloads.

With that foundation in place, we’ll turn to real-world usage patterns and common pitfalls: missing or redundant B-tree indexes, the subtleties of multi-column indexes, and handling of NULLs. From there, we’ll dig into PostgreSQL-specific behavior—from CREATE INDEX CONCURRENTLY to tracking index usage, identifying bloat, and safely deciding when to drop an index. Finally, we’ll explore the limitations of B-trees and when to consider alternative index types, like those for multidimensional or vector data. This talk is geared toward application developers who want to build faster, more efficient systems, gain a deeper understanding of this fundamental data structure, and avoid the silent costs of misused indexing.