This page shows you how to create a vectorizer in a self-hosted Postgres instance, then use the pgai vectorizer worker to create embeddings from data in your database. To finish off we show how simple it is to do a semantic search query on the embedded data in one query!
The local developer environment is a docker configuration you use to develop and test pgai, vectorizers and vectorizer worker locally. It includes a:
- Postgres deployment image with the TimescaleDB and pgai extensions installed
- pgai vectorizer worker image
On your local machine:
-
Create the Docker configuration for a local developer environment
Add the following docker configuration to
<timescale-folder>/docker-compose.yml
:name: pgai services: db: image: timescale/timescaledb-ha:pg16 environment: POSTGRES_PASSWORD: postgres OPENAI_API_KEY: <your-api-key> ports: - "5432:5432" volumes: - ./data:/var/lib/postgresql/data vectorizer-worker: image: timescale/pgai-vectorizer-worker:0.1.0 environment: PGAI_VECTORIZER_WORKER_DB_URL: postgres://postgres:postgres@db:5432/postgres OPENAI_API_KEY: <your-api-key>
-
Tune the developer image for your AI provider
Replace the instances of
OPENAI_API_KEY
with a key from your AI provider. -
Start the database
docker compose up -d db
To create and run a vectorizer, then query the auto-generated embeddings created by the vectorizer:
-
Connection to the database in your local developer environment
- Docker:
docker exec -it pgai-db-1 psql -U postgres
- psql:
psql postgres://postgres:postgres@localhost:5432/postgres
- Docker:
-
Enable pgai on your database
CREATE EXTENSION IF NOT EXISTS ai CASCADE;
-
Create the
blog
table with the following schemaCREATE TABLE blog ( id SERIAL PRIMARY KEY, title TEXT, authors TEXT, contents TEXT, metadata JSONB );
-
Insert some data into
blog
INSERT INTO blog (title, authors, contents, metadata) VALUES ('Getting Started with PostgreSQL', 'John Doe', 'PostgreSQL is a powerful, open source object-relational database system...', '{"tags": ["database", "postgresql", "beginner"], "read_time": 5, "published_date": "2024-03-15"}'), ('10 Tips for Effective Blogging', 'Jane Smith, Mike Johnson', 'Blogging can be a great way to share your thoughts and expertise...', '{"tags": ["blogging", "writing", "tips"], "read_time": 8, "published_date": "2024-03-20"}'), ('The Future of Artificial Intelligence', 'Dr. Alan Turing', 'As we look towards the future, artificial intelligence continues to evolve...', '{"tags": ["AI", "technology", "future"], "read_time": 12, "published_date": "2024-04-01"}'), ('Healthy Eating Habits for Busy Professionals', 'Samantha Lee', 'Maintaining a healthy diet can be challenging for busy professionals...', '{"tags": ["health", "nutrition", "lifestyle"], "read_time": 6, "published_date": "2024-04-05"}'), ('Introduction to Cloud Computing', 'Chris Anderson', 'Cloud computing has revolutionized the way businesses operate...', '{"tags": ["cloud", "technology", "business"], "read_time": 10, "published_date": "2024-04-10"}');
-
Create a vectorizer for
blog
SELECT ai.create_vectorizer( 'blog'::regclass, destination => 'blog_contents_embeddings', embedding => ai.embedding_openai('text-embedding-3-small', 768), chunking => ai.chunking_recursive_character_text_splitter('contents') );
-
Run the vectorizer worker
When you install pgai on Timescale Cloud, vectorizers are run automatically using TimescaleDB scheduling. For self-hosted, you run a pgai vectorizer worker so the vectorizer can process the data in
blog
.In a new terminal, start the vectorizer worker:
docker compose up -d vectorizer-worker
-
Check the vectorizer worker logs
docker compose logs -f vectorizer-worker
You see the vectorizer worker pick up the table and process it.
vectorizer-worker-1 | 2024-10-23 12:56:36 [info ] running vectorizer vectorizer_id=1
-
See the embeddings in action
Run the following search query to retrieve the embeddings:
SELECT chunk, embedding <=> ai.openai_embed('text-embedding-3-small', 'good food', dimensions=>768) as distance FROM blog_contents_embeddings ORDER BY distance;
The results look like:
chunk | distance |
---|---|
Maintaining a healthy diet can be challenging for busy professionals... | 0.6720892190933228 |
Blogging can be a great way to share your thoughts and expertise... | 0.7744888961315155 |
PostgreSQL is a powerful, open source object-relational database system... | 0.815629243850708 |
Cloud computing has revolutionized the way businesses operate... | 0.8913049921393394 |
As we look towards the future, artificial intelligence continues to evolve... | 0.9215681301612775 |
That's it, you're done. You now have a table in Postgres that pgai vectorizer automatically creates and syncs embeddings for. You can use this vectorizer for semantic search, RAG or any other AI app you can think of! If you have any questions, reach out to us on Discord.