refactor: rely on connector default for _respect_server_retry_after_header

The connector already defaults this parameter to False, so the
setdefault in credentials.py was redundant. Users opt in via
connection_parameters directly. Also fix the parameter name (was
renamed during connector PR review) and tighten upper bound to <4.1.6.

Co-authored-by: Isaac

Author: sd-db

CHANGELOG.md

@@ -11,6 +11,10 @@
 - Fix column order mismatch in microbatch and replace_where incremental strategies by using INSERT BY NAME syntax ([#1338](https://github.com/databricks/dbt-databricks/issues/1338))
 - Fix `dbt run --empty` failing with inline `ref()` / `source()` aliases ([dbt-labs/dbt-adapters#660](https://github.com/dbt-labs/dbt-adapters/issues/660))
 
+### Under the Hood
+
+- Bump `databricks-sql-connector` upper bound to `<4.1.6`, enabling users to opt into `_respect_server_retry_after_header` (available in connector 4.1.5) for server-directed retry behavior via `connection_parameters` ([#1363](https://github.com/databricks/dbt-databricks/pull/1363))
+
 ## dbt-databricks 1.11.6 (Mar 10, 2026)
 
 ### Features

dbt/adapters/databricks/credentials.py

@@ -73,7 +73,6 @@ def __pre_deserialize__(cls, data: dict[Any, Any]) -> dict[Any, Any]:
         data.setdefault("connection_parameters", {})
         data["connection_parameters"].setdefault("_retry_stop_after_attempts_count", 30)
         data["connection_parameters"].setdefault("_retry_delay_max", 60)
-        data["connection_parameters"].setdefault("_retry_server_directed_only", False)
         return data
 
     def __post_init__(self) -> None:

pyproject.toml

@@ -24,7 +24,7 @@ classifiers = [
 dependencies = [
     "click>=8.2.0, <9.0.0",
     "databricks-sdk>=0.68.0, <0.78.0",
-    "databricks-sql-connector[pyarrow]>=4.1.5, <4.2.0",
+    "databricks-sql-connector[pyarrow]>=4.1.1, <4.1.6",
     "dbt-adapters>=1.22.0, <1.23.0",
     "dbt-common>=1.37.0, <1.38.0",
     "dbt-core>=1.11.2, <1.11.7",

tests/unit/test_adapter.py

@@ -242,7 +242,6 @@ def _connect_func(
         expected_http_headers=None,
         expected_no_token=None,
         expected_client_creds=None,
-        expected_retry_params=None,
     ):
         def connect(
             server_hostname,
@@ -281,9 +280,6 @@ def connect(
                 assert http_headers is None
             else:
                 assert http_headers == expected_http_headers
-            if expected_retry_params is not None:
-                for key, value in expected_retry_params.items():
-                    assert kwargs.get(key) == value
             return Mock()
 
         return connect
@@ -359,40 +355,6 @@ def _test_databricks_sql_connector_http_header_connection(self, http_headers, co
             assert connection.credentials.token == "dapiXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"
             assert connection.credentials.schema == "analytics"
 
-    def test_databricks_sql_connector_default_retry_params(self):
-        """Verify default retry parameters are passed through to dbsql.connect().
-
-        Ensures _retry_stop_after_attempts_count, _retry_delay_max, and
-        _retry_server_directed_only defaults from __pre_deserialize__ reach
-        the connector.
-        """
-        self._test_databricks_sql_connector_connection(
-            self._connect_func(
-                expected_retry_params={
-                    "_retry_stop_after_attempts_count": 30,
-                    "_retry_delay_max": 60,
-                    "_retry_server_directed_only": False,
-                }
-            )
-        )
-
-    def test_databricks_sql_connector_retry_server_directed_only_opt_in(self):
-        """Verify user can opt in to _retry_server_directed_only via connection_parameters.
-
-        When a user sets _retry_server_directed_only: true in their profile,
-        the connector should only retry requests when the server includes a
-        Retry-After header, preventing duplicate writes from blind retries.
-        """
-        config = self._get_config(connection_parameters={"_retry_server_directed_only": True})
-        adapter = DatabricksAdapter(config, get_context("spawn"))
-
-        connect = self._connect_func(expected_retry_params={"_retry_server_directed_only": True})
-        with patch("dbt.adapters.databricks.handle.dbsql.connect", new=connect):
-            connection = adapter.acquire_connection("dummy")
-            connection.handle  # trigger lazy-load
-
-            assert connection.state == "open"
-
     @patch("dbt.adapters.databricks.api_client.DatabricksApiClient")
     def test_list_relations_without_caching__no_relations(self, _):
         with patch.object(DatabricksAdapter, "get_relations_without_caching") as mocked:
@@ -1396,39 +1358,18 @@ class TestDatabricksCredentialsPreDeserialize:
     """Tests for DatabricksCredentials.__pre_deserialize__ retry defaults."""
 
     def test_pre_deserialize__default_retry_params(self):
-        """Verify all retry defaults are set when connection_parameters is empty."""
+        """Verify retry defaults are set when connection_parameters is empty."""
         data = {"connection_parameters": {}}
         result = DatabricksCredentials.__pre_deserialize__(data)
         assert result["connection_parameters"]["_retry_stop_after_attempts_count"] == 30
         assert result["connection_parameters"]["_retry_delay_max"] == 60
-        assert result["connection_parameters"]["_retry_server_directed_only"] is False
 
     def test_pre_deserialize__missing_connection_parameters(self):
         """Verify retry defaults are set even when connection_parameters key is absent."""
-        data = {}
+        data: dict[Any, Any] = {}
         result = DatabricksCredentials.__pre_deserialize__(data)
         assert result["connection_parameters"]["_retry_stop_after_attempts_count"] == 30
         assert result["connection_parameters"]["_retry_delay_max"] == 60
-        assert result["connection_parameters"]["_retry_server_directed_only"] is False
-
-    def test_pre_deserialize__user_override_retry_server_directed_only(self):
-        """Verify user-provided _retry_server_directed_only is not overridden by default."""
-        data = {"connection_parameters": {"_retry_server_directed_only": True}}
-        result = DatabricksCredentials.__pre_deserialize__(data)
-        assert result["connection_parameters"]["_retry_server_directed_only"] is True
-
-    def test_pre_deserialize__user_override_preserves_other_defaults(self):
-        """Verify overriding one retry param does not affect the others."""
-        data = {
-            "connection_parameters": {
-                "_retry_stop_after_attempts_count": 5,
-                "_retry_server_directed_only": True,
-            }
-        }
-        result = DatabricksCredentials.__pre_deserialize__(data)
-        assert result["connection_parameters"]["_retry_stop_after_attempts_count"] == 5
-        assert result["connection_parameters"]["_retry_delay_max"] == 60
-        assert result["connection_parameters"]["_retry_server_directed_only"] is True
 
     def test_pre_deserialize__custom_params_preserve_retry_defaults(self):
         """Verify unrelated connection_parameters don't interfere with retry defaults."""
@@ -1437,4 +1378,3 @@ def test_pre_deserialize__custom_params_preserve_retry_defaults(self):
         assert result["connection_parameters"]["custom_param"] == "value"
         assert result["connection_parameters"]["_retry_stop_after_attempts_count"] == 30
         assert result["connection_parameters"]["_retry_delay_max"] == 60
-        assert result["connection_parameters"]["_retry_server_directed_only"] is False