pgvector-lua

pgvector support for Lua

Supports pgmoon

Getting Started

Run:

luarocks install pgvector

And follow the instructions for your database library:

• pgmoon

Or check out some examples:

• Embeddings with OpenAI
• Binary embeddings with Cohere
• Hybrid search with Ollama (Reciprocal Rank Fusion)
• Sparse search with Text Embeddings Inference

pgmoon

Require the library

localpgvector=require("pgvector")

Enable the extension

pg:query("CREATE EXTENSION IF NOT EXISTS vector")

Create a table

pg:query("CREATE TABLE items (id bigserial PRIMARY KEY, embedding vector(3))")

Insert a vector

localembedding=pgvector.new({1, 1, 1})
pg:query("INSERT INTO items (embedding) VALUES ($1)", embedding)

Get the nearest neighbors

localembedding=pgvector.new({1, 1, 1})
localres=pg:query("SELECT * FROM items ORDER BY embedding <-> $1 LIMIT 5", embedding)
fori, rowinipairs(res) doprint(row["id"])
end

Add an approximate index

pg:query("CREATE INDEX ON items USING hnsw (embedding vector_l2_ops)")
-- orpg:query("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

Reference

Half Vectors

Create a half vector from a table

localvec=pgvector.halfvec({1, 2, 3})

Sparse Vectors

Create a sparse vector from a table of non-zero elements

localelements= {[1] =1, [3] =2, [5] =3}
localvec=pgvector.sparsevec(elements, 6)

Get the number of dimensions

vec["dim"]

Get the non-zero elements

vec["elements"]

History

View the changelog

Contributing

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-lua.git
cd pgvector-lua
createdb pgvector_lua_test
luarocks install pgmoon
luarocks install luasocket
lua test/pgvector.lua

To run an example:

createdb pgvector_example
luarocks install luasec
luarocks install lua-cjson
lua examples/openai/example.lua