An AI assistant is planned. Until it is genuinely useful we would rather point you at the page that actually answers your question.
Vector similarity search inside PostgreSQL, our default when Postgres is already in the system and embeddings need to sit beside relational data.
Start Your Projectpgvector is an open-source PostgreSQL extension that adds a vector column type and similarity operators. You store embeddings in an ordinary table and query them with SQL, using exact search or approximate indexes (HNSW or IVFFlat) for speed.
Its strength is that vectors are just another column. A query can combine similarity with ordinary filters and joins, inside one transaction, protected by the same backups, roles and row-level security as the rest of your data.
Suitability
And when it is not. Choosing the wrong tool costs more than any implementation detail.
In practice
Adding retrieval to an application without introducing a new datastore, keeping documents, embeddings and permissions in one place.
Combining similarity search with row-level security so a user can only retrieve what they are allowed to see.
Pairing PostgreSQL full-text search with vector similarity in one query for results that respect both exact terms and meaning.
Considerations
Practical notes from running this in production.
Approximate indexes trade recall for speed. Tune index parameters against a labelled sample of real queries instead of accepting defaults, and measure recall rather than assuming it.
Index builds and memory use grow with the collection. Plan instance memory for the index, and rebuild on a copy when you change parameters.
Filtered approximate search can return fewer results than requested when a filter is very selective. Test selective filters explicitly, since this is the most common surprise in production.
Vectors are large. Storage, backup size and replication cost grow with embedding dimension, so choose the embedding model with that cost in mind.
FAQ
By industry
Where we apply pgvector. Tiles marked "Guide" open a dedicated write-up; the rest open the industry page.
Related
Tell us what you are trying to build or fix. We will come back with scope, approach and an honest view on cost and timeline.