[Bug]: Invalid namespace prefixes for PSQL

[JoramMillenaar]

Do you need to file an issue?

• I have searched the existing issues and this bug is not already filed.
• I believe this is a legitimate bug, not just a question or feature request.

Describe the bug

When you use lightrag with PSQL and AGE and pass a namespace prefix that starts with a number, the PSQL queries will fail and raise the following error. It seems that PSQL and AGE put restrictions on identifiers.

    raise PGGraphQueryException(
lightrag.kg.postgres_impl.PGGraphQueryException: {'message': "Error executing graph query: SELECT * FROM cypher('67c880chunk_entity_relation', $$\n                        MATCH (n:Entity)\n                        OPTIONAL MATCH (n)-[r]->(m:Entity)\n                        RETURN n, r, m\n                        LIMIT 1000\n                      $$) AS (n agtype, r agtype, m agtype)", 'wrapped': "SELECT * FROM cypher('67c880chunk_entity_relation', $$\n                        MATCH (n:Entity)\n                        OPTIONAL MATCH (n)-[r]->(m:Entity)\n                        RETURN n, r, m\n                        LIMIT 1000\n                      $$) AS (n agtype, r agtype, m agtype)", 'detail': 'graph name is invalid'}
^[[B^[[A^[[B^CINFO: Shutting down

Steps to reproduce

• Start a lightrag server using PSQL and age for all storage
  lightrag-server --namespace-prefix 67c880
• Call any endpoint or simply go to the webui and it will throw an error.

Expected Behavior

Perhaps an error should be thrown at initialization time, or some prefix should be added to the namespace-prefix (which is done for other identifiers, like the document ID being prefixed with 'doc-')

LightRAG Config Used

LLM_BINDING=openai
LLM_BINDING_HOST=https://api.openai.com/v1
LLM_MODEL=gpt-4o-mini
EMBEDDING_BINDING=openai
EMBEDDING_MODEL=text-embedding-3-small
EMBEDDING_DIM=1536

POSTGRES_USER=user
POSTGRES_DB=postgres
POSTGRES_PASSWORD=password
POSTGRES_DATABASE=postgres

LIGHTRAG_GRAPH_STORAGE=PGGraphStorage
LIGHTRAG_KV_STORAGE=PGKVStorage
LIGHTRAG_VECTOR_STORAGE=PGVectorStorage
LIGHTRAG_DOC_STATUS_STORAGE=PGDocStatusStorage

Logs and screenshots

No response

Additional Information

• LightRAG Version:
• Operating System:
• Python Version:
• Related Issues:

[danielaskdd]

WORKSPACE is introduce since v1.14.0, pls use workspace instead of namespace.