Database Configuration¶

Flexible GraphRAG uses four database types for hybrid search. Each is selected by a picker env var and configured via a per-store JSON config.

Note: RDF Ontologies are supported for both Property Graph and RDF Graph databases.

Framework Backends¶

Each pipeline stage can independently run on LlamaIndex (default) or LangChain:

GRAPH_BACKEND=llamaindex        # llamaindex | langchain
VECTOR_BACKEND=llamaindex       # llamaindex | langchain
SEARCH_BACKEND=llamaindex       # llamaindex | langchain
CHUNKER_BACKEND=llamaindex      # llamaindex | langchain
KG_EXTRACTOR_BACKEND=llamaindex # llamaindex | langchain
RETRIEVAL_FUSION=llamaindex     # llamaindex | langchain

LangChain-only property graph stores (ArangoDB, Apache AGE, HugeGraph, SurrealDB, TigerGraph, Cosmos Gremlin) auto-select GRAPH_BACKEND=langchain. Spanner uses LlamaIndex only (llama-index-spanner; LangChain's langchain-google-spanner is incompatible with langchain-core>=1.0).

Per-Store Configuration¶

Use {TYPE}_*_DB_CONFIG for per-store settings:

# Property graph
PG_GRAPH_DB=neo4j
NEO4J_GRAPH_DB_CONFIG={"uri": "bolt://localhost:7687", "username": "neo4j", "password": "password"}

# Vector
VECTOR_DB=qdrant
QDRANT_VECTOR_DB_CONFIG={"host": "localhost", "port": 6333}

# Search
SEARCH_DB=elasticsearch
ELASTICSEARCH_SEARCH_DB_CONFIG={"hosts": ["http://localhost:9200"], "index_name": "hybrid_search"}

Detailed Configuration Pages¶

• Property Graph Databases — all 15 stores (8 both LI+LC, 1 LI-only, 6 LC-only), database and framework config, skip_graph
• RDF Graph Databases — Fuseki, GraphDB, Oxigraph, Neptune RDF; database and framework config, skip_graph
• Vector Databases — 10 stores, LI and LC backends, dimension compatibility
• Search Databases — BM25, Elasticsearch, OpenSearch; LI and LC backends
• LangChain Configuration — framework pickers, retriever toggles, synonym expansion, scope tags
• LangChain Architecture — full dual-framework architecture, retriever layers, source labels in results

Per-Store Setup Guides¶

Detailed setup instructions for cloud-hosted and less common stores:

PostgreSQL¶

• PostgreSQL Setup — pgvector store (port 5433) and incremental state DB; pgAdmin at port 5050