Dev.to
6/25/2026

Vibe-Memory Part 3: pgvector Performance Optimization - How I Cut Query Time From 800ms to 15ms
Short summary
Developer optimized pgvector performance in a personal AI memory assistant using three techniques: switching from IVFFlat to HNSW indexing (5x faster), reducing embedding dimensions from 1536 to 512 (2x faster), and running VACUUM ANALYZE. Combined improvements cut query times from 800ms to 50ms.
- •IVFFlat to HNSW index switch reduced query time from 800ms to 150ms
- •Reducing embeddings from 1536 to 512 dimensions cut time to 70ms with minimal quality loss
- •VACUUM ANALYZE maintenance made performance consistent, gaining another 20ms improvement
Generated with AI, which can make mistakes.
Is this a good recommendation for you?



