How do you handle a "Delete" request in your vector database if a user wants their data removed (Right to be Forgotten)?

Why is "fixed-length" chunking often insufficient? How would you handle a document where a single sentence contains a critical fact but spans a chunk boundary?

How do you build a ground-truth dataset to evaluate if your RAG system is actually improving over time?

When would you choose between Cosine Similarity, Inner Product, and Euclidean Distance (L2) for your vector search?