Design a vector database / embedding retrieval service.
The service under every RAG stack and semantic search box. The signal is your ANN index choice and how you deal with the three things that quietly break it: metadata filtering, live updates, and scale.
Updated Sep 2026 · Grounded in real GenAI, LLM, and AI/ML engineering interview loops and written to a senior-engineer editorial bar.
The service under every RAG stack and semantic search box. The signal is your ANN index choice and how you deal with the three things that quietly break it: metadata filtering, live updates, and scale.
Lead with where the obvious approach breaks, because that is the judgment they are screening for — most candidates jump straight to the happy path and lose the room.
Then walk the failure back through the pipeline in order, naming the one metric the customer's exec sponsor actually cares about before you propose the fix.
