Combining Semantic Search and Full-Text Search in PostgreSQL (With Cohere, Pgvector, and Pgai)

This article discusses how to combine full-text search and semantic search in PostgreSQL using Cohere, Pgvector, and Pgai. Full-text search finds precise matches for keywords in a query, while semantic search understands the meaning of words and their relationships through vectors. Hybrid search combines the precision of keyword search with the contextual understanding of vector search, ensuring results are both precise and contextually relevant. The implementation involves using Cohere's embedding model and reranker, as well as leveraging Pgvector for efficient semantic searches on data and Pgai for AI-powered queries within PostgreSQL.