Definition
A vector database is a purpose-built database system designed to store, index, and query high-dimensional vector embeddings at scale. Unlike traditional databases that search based on exact matches or keyword similarity, vector databases perform approximate nearest neighbor (ANN) search, finding the vectors most similar to a query vector across millions or billions of stored embeddings in milliseconds.
Vector databases use specialized indexing algorithms like HNSW (Hierarchical Navigable Small World) or IVF (Inverted File Index) to make similarity search fast and efficient. They also support metadata filtering, allowing queries that combine semantic similarity with traditional attribute-based filters, such as "find the most relevant support article published in the last 30 days."
Why It Matters for Product Managers
Vector databases are a critical infrastructure decision for any product building AI-powered search, recommendations, or RAG features. The choice of vector database affects query latency, cost, scalability, and the quality of similarity results, all of which directly impact the user experience. PMs need to understand the trade-offs between managed services like Pinecone and Weaviate versus self-hosted options like Milvus or pgvector.
From a product roadmap perspective, vector databases determine how quickly the team can iterate on AI features. A well-chosen vector database makes it easy to update embeddings, add new content sources, and experiment with different retrieval strategies. A poor choice creates ongoing operational burden and limits the team ability to improve AI feature quality over time.
How It Works in Practice
Common Pitfalls
Related Concepts
Vector databases store and index Embeddings to enable the fast similarity search that Retrieval-Augmented Generation (RAG) pipelines depend on. They serve as the retrieval layer between user queries and the Large Language Model (LLM) that generates the final response.