Add workspace param for lightrag with PG storage

[jasperchen01]

Description

Add workspace param for lightrag with PG storage

Related Issues

#1573

Changes Made

1. Add workspace param in class StorageNameSpace(ABC)
2. Change milvus_impl.py to support the workspace collections
3. Change postgres_impl.py to support the workspace query
4. Change lightrag/lightrag.py to pass the workspace value when init the lightrag

Checklist

• Changes tested locally
• Code reviewed
• Documentation updated (if necessary)
• Unit tests added (if applicable)

Additional Notes

[Add any additional notes or context for the reviewer(s).]

[danielaskdd]

The PGGraphStorage class itself does not directly support data isolation through workspaces. The graph data from different workspaces will be stored in the same Apache AGE graph, which can cause LightRAG RAG to malfunction.

[danielaskdd]

In the current workflow, it seems that the workspace can only be set during the initialization of the LightRAG object. If you need to switch workspaces later, you have to create a new LightRAG object. Is my understanding correct? If so, is there a better way to switch workspaces?

[jasperchen01]

The PGGraphStorage class itself does not directly support data isolation through workspaces. The graph data from different workspaces will be stored in the same Apache AGE graph, which can cause LightRAG RAG to malfunction.

Yeah, you're correct, PGGraphStorage doesn't support the workspace, I'll check that again.

[jasperchen01]

In the current workflow, it seems that the workspace can only be set during the initialization of the LightRAG object. If you need to switch workspaces later, you have to create a new LightRAG object. Is my understanding correct? If so, is there a better way to switch workspaces?

Yes, it can not to dynamically switch workspace for my changes. I think if we wanna the ability to dynamically switch workspaces , we need to modify all insert/query interfaces to add a workspace parameter