Does getDefinition support DirectLake semantic models?

[jaryszek]

Hi,

I'm using the Fabric REST API to retrieve a semantic model definition:

POST /v1/workspaces/{workspaceId}/semanticModels/{semanticModelId}/getDefinition

This works for Import models, but I'm unsure about DirectLake semantic models.

Does getDefinition fully support DirectLake models?
Has anyone successfully retrieved the definition (TMDL) for a DirectLake semantic model using this API?

Thanks!

[jaryszek]

thank you, 

I tested it and got null as an answer (202). So it means that DirectLAke over OneLake is not working with this rest api. Any alternatives?

Best,
Jacek

[v-tejrama]

Hi @jaryszek ,

Receiving a 202 response from the getDefinition API does not mean that DirectLake semantic models are unsupported. In the Fabric REST API, this endpoint works as a long-running operation. A 202 Accepted response indicates that the request has been received and processing has started, but the definition is not yet ready, so the response body may be empty at this point.

The usual process is to use the operation details provided in the response headers, like the operation ID or location, and then check the operation status endpoint. Once the operation completes, you can retrieve the result, which will include the semantic model definition in TMDL format. This process is the same for Import, DirectQuery, or DirectLake storage modes.

The official documentation for the Fabric REST API Get Semantic Model Definition and the general guidance on long-running operations confirm that a 202 response means processing is underway and clients should poll the operation endpoint for the result.

Therefore, DirectLake over OneLake is not blocked by the API. The important step is to follow the long-running operation pattern after receiving the 202 response, rather than expecting the definition immediately. By doing this, you can retrieve the TMDL for the semantic model.

Thank you.

[AmosHersch]

@jaryszek If you got 202 (Accepted) it doesn't mean it is not working. See here how to get the result of a long running operation in Fabric APIs
Long running operations - Microsoft Fabric REST APIs | Microsoft Learn