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  • Writer's pictureSwapnish Khanolkar

Graph RAG vs Vector RAG: Demystifying Retrieval Augmented Generation

Retrieval-Augmented Generation (RAG) is a technique that empowers Large Language Models (LLMs) by providing them with relevant information alongside a user query. This "information retrieval" step enhances the LLMs ability to generate accurate and comprehensive responses. Here's how RAG queries work:

  1. User Query: The user asks a question or provides a prompt.

  2. Retrieval: The system searches for relevant information from a database based on the query's intent.expand_more

  3. Augmentation: The retrieved information is presented to the LLM alongside the user query.expand_more

  4. Generation: The LLM leverages both the query and retrieved information to generate a response.expand_more

There are two main approaches to information retrieval within RAG: Let's compare Graph RAG vs Vector RAG and delve deeper into each:

Vector RAG

Imagine a vast library where books are organized based on their thematic connections. Vector RAG employs vector databases. These databases represent information (like documents or entities) as numerical vectors in a high-dimensional space. Documents with similar meanings or topics will have vectors closer together in this space. During retrieval, Vector RAG searches the database for documents with vectors closest to the user query, essentially finding the most thematically relevant information.


  • User Query: "What are the causes of the French Revolution?"

  • Retrieved Information (Vector Search): Documents discussing historical events leading up to the French Revolution, documents on social and economic conditions in 18th century France.

  • Generated Response: The LLM, using the retrieved documents, might explain the various political, social, and economic factors that contributed to the French Revolution.

Graph RAG

Think of a detailed map where locations and their connections are clearly defined. Graph RAG utilizes knowledge graphs. These are structured databases that represent entities (like people, places, or events) and the relationships between them. During retrieval, Graph RAG traverses the knowledge graph based on the user query, identifying entities and relationships relevant to the user's intent. This approach provides a deeper understanding of the context and connections within the retrieved information.


  • User Query: "Who wrote the Lord of the Rings trilogy?"

  • Retrieved Information (Graph Traversal): Entity for J.R.R. Tolkien with a relationship of "author" to another entity representing the "Lord of the Rings" trilogy.

  • Generated Response: The LLM, using the knowledge graph, would identify J.R.R. Tolkien as the author of the Lord of the Rings trilogy.

Graph RAG vs Vector RAG: A Showdown

The key difference between Graph RAG and Vector RAG boils down to how they represent and retrieve information for the LLM.

  • Vector RAG:  Think of it as finding similar books in a library. It uses vector databases where information is stored as numerical codes. These codes capture the meaning and themes of the information. During retrieval, Vector RAG searches for information (documents, entities) with codes closest to the user query, essentially finding the most thematically relevant information.

  • Graph RAG: Imagine navigating a detailed map to find connected locations. It uses knowledge graphs which map entities (like people, places, events) and their relationships. When processing a query, Graph RAG explores the knowledge graph, identifying entities and connections relevant to the user's intent. This approach provides a deeper understanding of the context and relationships within the information.

Thematic relevance vs. Context and Relationships:

  • Thematic relevance focuses on how similar topics are. Imagine two documents, one about the French Revolution and another about the American Revolution. Both discuss revolutions, making them thematically relevant to a query about "revolutions."

  • Context and Relationships delve deeper. Here, we consider not just the topics but also the connections between them. The knowledge graph in Graph RAG might show that the American Revolution was inspired by the French Revolution, providing a richer understanding of the context.

Information vs. Entities:

  • Information is a broader term encompassing any kind of knowledge retrieved. In Vector RAG, retrieved information could be entire documents or summaries.

  • Entities are specific objects or concepts within the information. In Graph RAG, the retrieved information focuses on identifying entities (like the French Revolution) and the relationships between them (e.g., historical event with causes).

Choosing the Right RAG Approach

The choice between Vector RAG and Graph RAG depends on your specific needs. Vector RAG excels at finding thematically relevant information in large datasets, ideal for tasks like document search or product recommendations. Graph RAG shines when you require a deeper understanding of context and relationships, making it valuable for question answering tasks or knowledge base completion. Additionally, some systems even combine both approaches for a hybrid solution, leveraging the strengths of each.

Ultimately, both Vector RAG and Graph RAG represent exciting advancements in leveraging LLMs. By providing them with relevant information, we unlock their true potential to deliver informative and insightful responses.

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