{"record":{"id":"f239a4171a755208","repo":"mlflow/mlflow","slug":"createlocation-response-did-not-include-uc-table-p","errorCode":null,"errorMessage":"CreateLocation response did not include uc_table_prefix.","messagePattern":"CreateLocation response did not include uc_table_prefix\\.","errorType":"exception","errorClass":"MlflowException","httpStatus":null,"severity":"error","filePath":"mlflow/store/tracking/databricks_rest_store.py","lineNumber":249,"sourceCode":"    def create_or_get_trace_location(\n        self,\n        location: UnityCatalogEntity,\n        sql_warehouse_id: str | None = None,\n    ) -> UnityCatalogEntity:\n        request_proto = CreateLocation(\n            uc_table_prefix=uc_table_prefix_location_to_proto(location),\n            sql_warehouse_id=self._resolve_sql_warehouse_id(sql_warehouse_id),\n        )\n        req_body = message_to_json(request_proto)\n        response_proto = self._call_endpoint(\n            CreateLocation,\n            req_body,\n            endpoint=_V5_TRACE_LOCATION_ENDPOINT,\n            response_proto=CreateLocation.Response(),\n        )\n        if response_proto.HasField(\"uc_table_prefix\"):\n            return uc_table_prefix_location_from_proto(response_proto.uc_table_prefix)\n        raise MlflowException(\"CreateLocation response did not include uc_table_prefix.\")\n\n    def link_trace_location(\n        self,\n        experiment_id: str,\n        location: UnityCatalogEntity,\n    ) -> None:\n        request_proto = LinkTraceLocation(\n            experiment_id=experiment_id,\n            uc_table_prefix=uc_table_prefix_location_to_proto(location),\n        )\n        req_body = message_to_json(request_proto)\n        self._call_endpoint(\n            LinkTraceLocation,\n            req_body,\n            endpoint=f\"/api/5.0/mlflow/experiments/{experiment_id}/trace-location:link\",\n            response_proto=LinkTraceLocation.Response(),\n        )\n        _logger.debug(f\"Linked experiment {experiment_id} to trace location: {location}\")","sourceCodeStart":231,"sourceCodeEnd":267,"githubUrl":"https://github.com/mlflow/mlflow/blob/6a27f2decc0b76eb1b54af31849784addb357dbc/mlflow/store/tracking/databricks_rest_store.py#L231-L267","documentation":"create_or_get_trace_location POSTs to the v5 CreateLocation endpoint and expects CreateLocation.Response to contain uc_table_prefix. When the returned proto lacks that field the store cannot construct the UnityCatalogEntity location and raises this MlflowException, meaning provisioning did not return the expected UC table prefix.","triggerScenarios":"Calling create_or_get_trace_location (or _create_or_get_trace_location) where the server's CreateLocation.Response arrives without uc_table_prefix set — e.g. warehouse not resolved/running, server doesn't support UC table prefixes for traces, or the create silently degraded.","commonSituations":"First-time provisioning of UC-backed tracing on a workspace with an older API; missing MLFLOW_TRACING_SQL_WAREHOUSE_ID causing a degraded create path; server/client MLflow version skew.","solutions":["Set MLFLOW_TRACING_SQL_WAREHOUSE_ID and ensure the warehouse is running before creating the location.","Upgrade/align MLflow client and server versions that both support uc_table_prefix in CreateLocation responses.","Check the created location in the Databricks workspace (Unity Catalog) to see whether the table was actually provisioned, then retry or clean up."],"exampleFix":null,"handlingStrategy":"try-catch","validationCode":null,"typeGuard":null,"tryCatchPattern":"try:\n    loc = store.create_or_get_trace_location(location, sql_warehouse_id)\nexcept MlflowException as e:\n    if \"did not include uc_table_prefix\" in str(e):\n        # retry after ensuring warehouse is running / versions aligned\n        ensure_warehouse_running(sql_warehouse_id)\n        loc = store.create_or_get_trace_location(location, sql_warehouse_id)","preventionTips":["Ensure the SQL warehouse exists and is running before provisioning.","Set MLFLOW_TRACING_SQL_WAREHOUSE_ID up front.","Align client/server MLflow versions before adopting v5 trace-location APIs."],"tags":["databricks","unity-catalog","traces","response-parsing","version-mismatch"],"backgroundTag":"unexpected-server-response","analyzedSha":"6a27f2decc0b76eb1b54af31849784addb357dbc","analyzedAt":"2026-08-29T20:54:51.419Z","schemaVersion":2},"datasetVersion":"2026-08-29T22:17:34.462Z"}