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Search Databases

Flexible GraphRAG supports three full-text search options for the hybrid search pipeline. Set SEARCH_DB to select the store and SEARCH_BACKEND to choose the framework (llamaindex or langchain).

BM25 (Built-in)

Local in-memory BM25 full-text search with TF-IDF ranking. No external server required.

  • Best for: Local development, simple deployments
SEARCH_DB=bm25
BM25_SEARCH_DB_CONFIG={"persist_dir": "./bm25_index"}

Elasticsearch

Enterprise search engine with advanced analyzers, faceted search, and real-time analytics.

  • Dashboard: Kibana at http://localhost:5601
  • Docker: Uncomment includes/elasticsearch-dev.yaml in docker-compose.yaml
SEARCH_DB=elasticsearch
ELASTICSEARCH_SEARCH_DB_CONFIG={"hosts": ["http://localhost:9200"], "index_name": "hybrid_search"}

OpenSearch

AWS-led open-source fork with native hybrid scoring (vector + BM25) and k-NN algorithms.

  • Dashboard: OpenSearch Dashboards at http://localhost:5602
  • Docker: Uncomment includes/opensearch.yaml in docker-compose.yaml (and includes/opensearch-dashboards.yaml for the web UI — it is a separate include)
SEARCH_DB=opensearch
OPENSEARCH_SEARCH_DB_CONFIG={"hosts": ["http://localhost:9201"], "index_name": "hybrid_search"}

For optimal hybrid search with OpenSearch, OpenSearch needs the hybrid search pipeline (hybrid-search-pipeline). includes/opensearch.yaml creates it on every start (a one-off opensearch-init container that PUTs docker/config/opensearch-hybrid-search-pipeline.json). For an OpenSearch you run yourself, create it with:

python scripts/create_opensearch_pipeline.py

Sharing the engine with Alfresco

Alfresco Community 26.2 dropped Solr and indexes into Elasticsearch or OpenSearch too. By default includes/alfresco-elasticsearch.yaml gives it a dedicated engine on port 9202 (or includes/alfresco-opensearch.yaml on 9203), but you can point it at the one configured above instead: drop both includes and set ALFRESCO_SEARCH_HOST=elasticsearch (or =opensearch) in docker/.env. Alfresco writes its own alfresco index, so it coexists with hybrid_search, and your existing Kibana / OpenSearch Dashboards covers both. The includes/elasticsearch-dev.yaml (8.17.10) and includes/opensearch.yaml (2.19.6) pins match the versions ACS 26.2 is tested against, so no version change is needed.

Disabling Full-Text Search

SEARCH_DB=none