Naive RAG

In this lesson, we explore the simplest form of Retrieval-Augmented Generation (RAG), known as Naive RAG. This method follows a straight-forward pipeline by converting inputs to vector embeddings, executing a similarity search, and using the retrieved context to generate responses.

Overview of the Workflow

The process begins by transforming a user's query into a vector embedding using a dedicated embedding model. This embedding is then compared against pre-processed documents stored in a vector store. Since language models have context window limitations, documents—such as PDFs converted to text—must be split into manageable chunks. It is essential to use the same embedding model for both the query and the documents to ensure consistency in vector space.

The typical workflow involves the following steps:

1. Transform the user's query into an embedding.
2. Divide documents into manageable chunks.
3. Create embeddings for each document chunk using the same model.
4. Perform a similarity search to retrieve the most relevant chunks.
5. Augment the query with the retrieved context and pass it to the generative model to produce a response.

Embedding Models

There are several embedding models available for use. Common options include Cohere Embed version 3 and OpenAI’s text embedding model. Numerous competitive open-source alternatives can also be found on platforms like Hugging Face.

Document Chunking Techniques

Effective chunking is vital for creating a robust RAG system. Various strategies include:

• Fixed-size chunking: Splits text into equally sized segments.
• Sentence-based chunking: Divides text at sentence boundaries.
• Semantic chunking: Groups together contextually related content.
• Sliding window chunking: Creates overlapping chunks to maintain contextual continuity.
• Hierarchical chunking: Organizes text in a multi-level structure according to content hierarchy.

Choosing the right chunking method depends on the data characteristics and often requires iterative evaluation to optimize performance.

Advantages of Naive RAG

Despite its simplicity, Naive RAG offers several benefits:

• Ease of implementation.
• Cost-effectiveness.
• Reduced hallucination due to grounding provided by the retrieved context.

Limitations of Naive RAG

However, Naive RAG also has significant limitations that should be considered:

• Tightly coupled system components hinder parallel processing.
• Sequential execution may result in increased latency.
• Scalability challenges and a limitation on retrieval quality could impact the overall response quality.

Conclusion

While Naive RAG provides a highly accessible and cost-effective solution for basic applications, its inherent limitations in scalability and performance indicate the need for more advanced strategies in larger or more complex scenarios. Future lessons will delve into these advanced techniques to overcome the constraints of the naive approach.