ANN

Introduction The explosion of unstructured data—images, video, audio, text, and sensor streams—has forced modern search engines to move beyond traditional keyword matching. Multimodal search refers to the capability of retrieving relevant items across different media types using a single query that may itself be multimodal (e.g., an image plus a short text caption). At the heart of this capability lies vector similarity search: every item is embedded into a high‑dimensional vector space where semantic similarity translates to geometric proximity. While single‑node approximate nearest neighbor (ANN) libraries such as Faiss, Annoy, or Milvus can handle millions of vectors, real‑world deployments often need to serve billions of vectors, guarantee low latency under heavy load, and support hybrid queries that combine vector similarity with traditional filters (date ranges, categories, user permissions, etc.). ...