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GraphRAG — Knowledge-Graph Retrieval

docs/content/Sources/GraphRAG.mdx

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import { Callout } from 'nextra/components' import Image from 'next/image'

GraphRAG

GraphRAG augments classic vector retrieval with a knowledge graph. During ingestion DocsGPT uses an LLM to extract entities and the relationships between them from a source's chunks, and stores them as a graph alongside the vectors. At query time, a graph retriever uses Personalized PageRank (PPR) to walk that graph from the entities mentioned in your question, surfacing connected context that pure similarity search can miss — useful for multi-hop questions and queries that span related concepts.

<Callout type="warning" emoji="⚠️"> GraphRAG is **flag-gated** and currently **pgvector-only**. It is available only when both `GRAPHRAG_ENABLED=true` **and** `VECTOR_STORE=pgvector`. On any other vector store the enable action is rejected. </Callout>

Requirements

  • A PostgreSQL database with the pgvector extension (VECTOR_STORE=pgvector). See PostgreSQL for User Data.
  • GRAPHRAG_ENABLED=true in your environment.
  • An LLM configured for extraction (GraphRAG reuses your instance default model unless you override it).
env
GRAPHRAG_ENABLED=true
VECTOR_STORE=pgvector

The graph tables live in the same pgvector database as your embeddings and are sized to the embedding dimension. If you change embedding models you must re-ingest and re-extract (see Embeddings).

How it works

  1. Choose GraphRAG for the source — either at upload time, or by enabling it on an existing source (see below). This sets the source's config to graphrag mode.
  2. Extraction runs over the source's chunks. For each chunk, the LLM extracts entities and relations, which are written into per-source graph tables. Extraction is durable and resumable via a checkpoint, so it survives restarts and re-runs from scratch each time you re-enable it.
  3. Query. Questions against the source are routed to the graph retriever, which runs Personalized PageRank from the query's entities to gather related context.
<Callout type="info" emoji="ℹ️"> If a source has no graph yet (extraction still running or failed), the graph retriever **falls back to classic vector retrieval** for that source — answers keep working, they just don't use the graph until it is ready. </Callout>

Enabling GraphRAG

When you upload a new document, open Advanced settings and set Retriever to GraphRAG (the same dropdown also offers Hybrid). The source is created in graphrag mode and extraction is enqueued as part of ingestion — no extra step.

<Image src="/graph-rag-settings-before-upload.png" alt="Upload dialog advanced settings showing the Retriever dropdown with Classic, Hybrid, and GraphRAG options" width={661} height={945} />

These are the same per-source retrieval settings you can change later — choosing the retriever up front just avoids a re-ingest.

On an existing source

To turn an already-ingested source into a GraphRAG source, use the Enable GraphRAG action on the source (it shows a status badge while extraction runs), or call the API:

bash
curl -X POST https://your-docsgpt/api/sources/<source_id>/graphrag/enable \
  -H "Authorization: Bearer <token>"

The response returns a task_id for the extraction job:

json
{ "success": true, "task_id": "..." }

Notes:

  • Requires write access to the source (owner or team editor).
  • Returns 400 if GraphRAG isn't available on the workspace (wrong vector store or flag off).
  • Re-running the action rebuilds the graph from scratch rather than no-opping against an existing one.
  • You cannot switch a source to graphrag through the config PATCH endpoint — use the upload-time selector or this dedicated endpoint.

Configuration

Instance-wide settings (see App Configuration):

SettingDefaultDescription
GRAPHRAG_ENABLEDfalseMaster switch for the feature.
GRAPHRAG_EXTRACTION_MODELnullModel used for extraction. null reuses the instance default model.
GRAPHRAG_MAX_CHUNKS_FOR_EXTRACTION2000Hard cap on how many chunks are extracted per source (cost control).

Per-source extraction knobs live under the source config's graph object and override the instance defaults:

FieldDefaultDescription
extraction_modelnullOverride the extraction model for this source.
max_chunksnullOverride the chunk cap; null falls back to GRAPHRAG_MAX_CHUNKS_FOR_EXTRACTION.
gleanings0Extra extraction passes per chunk to catch entities missed on the first pass. Off by default (each pass costs additional LLM calls).
<Callout type="warning" emoji="⚠️"> Graph extraction makes an LLM call per chunk (more if `gleanings > 0`), so it has a real token cost. The cost is attributed to token usage under a `graph_extraction` tag, and the `max_chunks` cap bounds it. </Callout>

Visualizing the graph

GraphRAG sources expose a graph view in the UI — an interactive network of the extracted entities and relationships. It is backed by two read endpoints:

text
GET /api/sources/<source_id>/graph                    # bounded {nodes, edges} overview
GET /api/sources/<source_id>/graph/node/<node_id>     # one node and its neighbors

The overview is bounded to a default node limit to keep large graphs responsive.