What is Vector Database?
A vector database stores numerical embeddings of text, images, or audio and lets you retrieve semantically similar items by similarity search.
Definition
A vector database is the storage layer of RAG. It stores embeddings — numerical vector representations of text, images, or audio — and provides efficient similarity search (typically cosine or Euclidean distance). When a user asks a question, you embed the query and find the most similar stored vectors. In 2026 the production options are: pgvector (free, runs in your existing Postgres, our default for <1M docs), Pinecone (managed, serverless, great at scale), Weaviate (open-source, feature-rich), and Qdrant (Rust-native, fast).
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