This document describes how to create and run vectorizers from Python.

Installation

First, install the pgai library:

pip install pgai

Then, you need to install the necessary database tables and functions. All database objects will be created in the ai schema. This is done by running the following Python code:

import pgai

pgai.install(DB_URL)

Creating vectorizers from python

To help you create vectorizers from python, pgai provides the CreateVectorizer helper class. This class makes it easy to generate the create_vectorizer SQL statement, by giving you a pythonic interface. It accepts all the options listed in the SQL API and exposes the to_sql method to generate a SQL query which you can then run through the SQL library of your choice:

from pgai.vectorizer import CreateVectorizer
from pgai.vectorizer.configuration import EmbeddingOpenaiConfig, ChunkingCharacterTextSplitterConfig, FormattingPythonTemplateConfig, LoadingColumnConfig, DestinationTableConfig

vectorizer_statement = CreateVectorizer(
    source="blog",
    name="blog_content_embedder",  # Optional custom name for easier reference
    destination=DestinationTableConfig(
        destination='blog_embeddings'
    ),
    loading=LoadingColumnConfig(column_name='content'),
    embedding=EmbeddingOpenaiConfig(
        model='text-embedding-3-small',
        dimensions=768
    ),
    chunking=ChunkingCharacterTextSplitterConfig(
        chunk_size=800,
        chunk_overlap=400,
        separator='.',
        is_separator_regex=False
    ),
    formatting=FormattingPythonTemplateConfig(template='$title - $chunk')
).to_sql()

Then, you can run this statement using the PostgreSQL library of your choice. For example, using the psycopg library:

import psycopg

with psycopg.connect(conn_string) as conn:
    with conn.cursor() as cursor:
        cursor.execute(vectorizer_statement)

Running the vectorizer worker

You can then run the vectorizer worker using the the CLI tool or the Worker class discussed in the vectorizer worker documentation.
Note that you will need to install pgai with the vectorizer-worker extra to run the worker yourself:

pip install pgai[vectorizer-worker]

Related integrations

• SQLAlchemy integration
• Alembic integration