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Vector Search
Nearest-neighbor retrieval over embedding vectors — semantic search that matches meaning, not just words.
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Vector search retrieves documents by the closeness of their embedding vectors to the query’s vector. Because the vectors encode meaning, a question about ‘how do I reset my password’ can retrieve a document that says ‘change your credentials’ without either sharing keywords. Module 2 implements it three ways in the course: minsearch (an in-memory approach), sqlitesearch, and PGVector for Postgres.
The module also teaches the operational layer: indexing the whole knowledge base, querying efficiently, and combining scores. It is the retrieval engine for the RAG pipeline — and, via the hybrid-search module, half of an even stronger combined retriever.