Cianplan

Level 5: AI / LLM systems · L5.2 RAG & vector databases

HNSW and index trade-offs

Compare HNSW, IVF-PQ and DiskANN on recall, latency and memory.

12 min · Pro

What you take away

  • An approximate index trades recall for latency and memory; recall@k is a dial you set, not a defect.

And 3 more inside the class, in Pro.

How the class is laid out

  1. The problem
  2. The dial is recall
  3. Filtering is where it breaks
  4. Check your understanding