Introduction
In the previous blog, we explored how Retrieval-Augmented Generation (RAG) can augment the capabilities of GPT models. This post takes it a step further by demonstrating how to build a system that creates and stores embeddings from a document set using LangChain and Pgvector, allowing us to feed these embeddings to OpenAI's GPT for enhanced and contextually relevant responses.
1. The Role of Embeddings in RAG Systems
Embeddings represent text data in a dense numerical format, which helps models capture the semantic meaning of the text. By storing these embeddings in a database like Pgvector, we can efficiently retrieve the most relevant pieces of information and feed them into a model, like GPT, to enhance its ability to answer queries.
2. Installation and Setup
Before diving into the code, let’s go over the installation steps to set up the environment with LangChain, Pgvector, and OpenAI.
Step 1: Install the Required Libraries
You’ll need the following Python libraries to get started:
- langchain: A framework to work with LLMs and build AI applications.
- pgvector: A Postgres extension that supports vector embeddings storage and similarity search.
- psycopg2-binary: A PostgreSQL adapter for Python to handle database interactions.
Step 2: Set up Pgvector in PostgreSQL
To store embeddings in Pgvector, your PostgreSQL instance needs the Pgvector extension installed. Here's how to install and configure it:
- Install Pgvector (if not already installed):
Step 3: Set Up OpenAI API Access
You’ll need an OpenAI API key to generate embeddings and interact with GPT models.
- Go to OpenAI API to sign up or log in.
- Get your API key and store it in an environment variable:
With these installations in place, you’re ready to move on to loading, embedding, and querying your documents.
3. Loading the Document Data
Splitting the documents into smaller chunks ensures that each chunk can be embedded individually, improving retrieval accuracy.
4. Creating and Storing Embeddings
Once we have our text data, we can generate embeddings using LangChain and store them in Pgvector.
5. Querying the Database for Relevant Data
Now that the embeddings are stored, we can retrieve the most relevant documents based on a query.
6. Generating a Response with OpenAI
With the relevant context retrieved, we now use OpenAI’s GPT model to generate a response.
Conclusion
In this guide, we’ve shown how to set up LangChain with Pgvector to create and store document embeddings, query them for relevant context, and use the context to generate a response using OpenAI’s GPT model. This approach provides a powerful system for generating accurate, contextually informed answers.