The original headline is: "Filtered Vector Search: Where Every Benchmark Quietly Lies to You"

Short summary

Vector database benchmarks hide their biggest lie: they don't filter. In production, adding a WHERE clause can triple latency and tank recall because the approximate-nearest-neighbor graph assumes all nodes are reachable. Post-filtering breaks on tight filters; pre-filtering breaks on large subsets; the solution combines both strategically across the selectivity spectrum.

• •Vector search benchmarks exclude WHERE clauses, masking real production latency and recall problems
• •Post-filtering works for loose filters but fails when most data is excluded; pre-filtering has opposite failure modes
• •Optimal approach varies by filter selectivity—a hybrid third method covers the middle ground where most queries live

Generated with AI, which can make mistakes.