pgvector support for Haskell

Supports postgresql-simple

Add this line to your application’s .cabal file under build-depends:

pgvector >= 0.1 && < 0.2

And follow the instructions for your database library:

• postgresql-simple

Import the library

import Pgvector

Enable the extension

execute_ conn "CREATE EXTENSION IF NOT EXISTS vector"

Create a table

execute_ conn "CREATE TABLE items (embedding vector(3))"

Insert a vector

execute conn
    "INSERT INTO items (embedding) VALUES (?)"
    [Vector [1, 1, 1]]

Get the nearest neighbors

let q = "SELECT embedding FROM items ORDER BY embedding <-> ? LIMIT 5"
forEach conn q [Vector [1, 1, 1]] $ \(Only embedding) ->
    putStrLn $ show (embedding :: Vector)

Add an approximate index

execute_ conn "CREATE INDEX ON items USING hnsw (embedding vector_l2_ops)"
-- or
execute_ conn "CREATE INDEX ON items USING ivfflat (embedding vector_l2_ops) WITH (lists = 100)"

Use vector_ip_ops for inner product and vector_cosine_ops for cosine distance

See a full example

View the changelog

Everyone is encouraged to help improve this project. Here are a few ways you can help:

• Report bugs
• Fix bugs and submit pull requests
• Write, clarify, or fix documentation
• Suggest or add new features

To get started with development:

git clone https://github.com/pgvector/pgvector-haskell.git
cd pgvector-haskell
createdb pgvector_haskell_test
cabal test