After testing your connection, you can review the status of your specified endpoints to verify that they have been successfully sampled by the driver. Reviewing the status of your endpoints allows you to immediately identify any data omitted from the model and the potential causes. To review your endpoint status, query the INFORMATION_SCHEMA.SYSTEM_SAMPLING_STATUS system table. For example: 
SELECT * FROM INFORMATION_SCHEMA.SYSTEM_SAMPLING_STATUS
The driver generates the INFORMATION_SCHEMA.SYSTEM_SAMPLING_STATUS table after connecting to and sampling the endpoints specified in your Model. The table contains the following information:
  • ENDPOINT_NAME: The name of the endpoint as defined in the Model file.
  • MESSAGE: The HTTP response message.
  • SAMPLE_URI: The endpoint that was used for the connection.
  • SUCCESS: Indicates whether the endpoint was successfully sampled.
  • HTTP_STATUS: The HTTP response status code.
  • PRIMARY_KEY_CANDIDATES: A ranked list of potential primary key candidates that starts with the best-rated candidate.
Note that, in certain situations, you might need to set the Sampling Failure Tolerance option to -1 (SamplingFailureTolerance=-1) to receive the status for all your endpoints. For example, if the number of endpoints in your model that are unreachable exceeds the sampling failure tolerance set by Sampling Failure Tolerance, the driver will fail the connection and stop attempting to sample the remaining endpoints specified in your Model file. In that scenario, you will need to reconfigure Sampling Failure Tolerance to audit your complete set of endpoints.