Vector Databases for Memory

Master how AI agents use vector databases to store, search, and retrieve embeddings for semantic memory

Beyond Keyword Search

Traditional databases excel at exact matchingβ€”finding records where a field equals a specific value. But AI agents need semantic search: finding information based onmeaning, not just keywords.

Vector databases solve this by storing data as embeddings (numerical representations of meaning) and enabling similarity search. Instead of "WHERE name = 'iPhone'", agents ask "FIND SIMILAR TO this concept."

This is the infrastructure powering semantic memory, RAG (Retrieval-Augmented Generation), and intelligent memory systems.

Interactive: Traditional vs Vector Search

Toggle between search methods to see how they handle the query: "iPhone"

πŸ”

Traditional Keyword Search

Exact string matching: finds "iPhone" only where it appears literally.

Query: WHERE text LIKE '%iPhone%'
Apple iPhone 15
Exact keyword: "iPhone"
iPhone repair services
Exact keyword: "iPhone"
Limitation: Misses "smartphone", "mobile device", "Apple phone" β€” conceptually related but different words.

🎯 Why Agents Need Vector DBs

  • β€’Semantic Memory: Store and recall knowledge by meaning, not keywords
  • β€’RAG Systems: Retrieve relevant context for LLM queries
  • β€’Long-Term Memory: Store unlimited conversations with semantic recall
  • β€’Pattern Matching: Find similar past situations to inform decisions

πŸ—οΈ Core Components

  • β€’Embeddings: Numerical representations of text/data (vectors)
  • β€’Similarity Metrics: Cosine, dot product, Euclidean distance
  • β€’Indexes: HNSW, IVF, FAISS for fast nearest neighbor search
  • β€’Metadata Filtering: Combine semantic search with attribute filters

βš™οΈ How Vector Databases Work

1
Encode: Convert text/data into embeddings using a model (e.g., OpenAI, Cohere, sentence-transformers)
"iPhone review" β†’ [0.23, -0.45, 0.12, ..., 0.67] (1536 dimensions)
2
Store: Save embeddings with metadata in vector database (Pinecone, Weaviate, Qdrant, Chroma)
Each record: vector + metadata (original text, tags, timestamps, etc.)
3
Query: Encode query text, search for nearest neighbor vectors
Returns top K most similar items ranked by distance/similarity score
4
Use: Agent retrieves relevant context and uses it to inform responses
"User asked about smartphones β†’ retrieve iPhone, Android docs β†’ augment LLM context"