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Embedding & Indexing

Embedding models and vector indexing for RAG: choosing embeddings, HNSW vs IVF, dimensionality, and index optimization.

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Embedding & Indexing

Where the pipeline turns text into math. The biggest misconception: a vector database does not store your documents — it stores vectors and metadata, and the text lives elsewhere. Get this data layer right and search stays fast and cheap.

THE CENTRAL IDEA

Embedding maps each chunk to a point in high-dimensional space where meaning becomes distance — similar text lands nearby. Indexing then makes finding those neighbors fast: at millions of vectors you cannot compare against every one, so an approximate-nearest-neighbor (ANN) index like HNSW trades a sliver of recall for orders-of-magnitude speed. Two rules keep you out of trouble: embed queries and documents with the same model, and store the text separately from the vectors.

Vector Storage Architecture — Where Everything Lives

The biggest misconception about vector databases: they do NOT store your documents. They store vectors (arrays of floats) and metadata. The actual text lives elsewhere. Understanding this architecture is critical for production systems.

What Goes Where

Two stores — vectors here, text there

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