The vector engine showdown nobody was telling the truth about

At OpenSearchCon Europe 2026, Fernando Rejon Barrera presented a study comparing Lucene’s HNSW, Faiss, and jVector under realistic production workloads rather than isolated benchmarks. The research revealed that performance gaps stem from internal factors like memory management and concurrency handling rather than just raw speed. Ultimately, the findings suggest there is no single winning engine, as selection should be based on specific system complexities and actual query patterns.