diff --git a/backend/apps/db/db.py b/backend/apps/db/db.py
index 9ca87129..4237809f 100644
--- a/backend/apps/db/db.py
+++ b/backend/apps/db/db.py
@@ -216,7 +216,7 @@ def get_driver_connection(ds: CoreDatasource | AssistantOutDsSchema, db_config:
         if not use_pool:
             conn = pymysql.connect(user=conf.username, passwd=conf.password, host=conf.host,
                                    port=conf.port, db=conf.database, connect_timeout=conf.timeout,
-                                   read_timeout=conf.timeout, **conn_conf,
+                                   read_timeout=conf.timeout,
                                    **args)
         else:
             conn = PooledDB(
diff --git a/backend/tests/test_doris_starrocks_connection.py b/backend/tests/test_doris_starrocks_connection.py
new file mode 100644
index 00000000..6c416a5f
--- /dev/null
+++ b/backend/tests/test_doris_starrocks_connection.py
@@ -0,0 +1,135 @@
+"""Regression coverage for Doris/StarRocks connection parameter forwarding."""
+
+import ast
+import json
+from pathlib import Path
+from types import SimpleNamespace
+from unittest.mock import Mock
+
+import pytest
+
+from apps.datasource.models.datasource import DatasourceConf
+
+SOURCE = Path(__file__).parents[1] / "apps" / "db" / "db.py"
+
+
+@pytest.fixture
+def driver_connection():
+    """Load production functions without importing unrelated database drivers."""
+    nodes = ast.parse(SOURCE.read_text(encoding="utf-8")).body
+    selected = [
+        node
+        for node in nodes
+        if isinstance(node, ast.FunctionDef)
+        and node.name in {"get_extra_config", "get_driver_connection"}
+    ]
+    connect = Mock()
+    pool = Mock()
+    driver = SimpleNamespace(connect=connect)
+    namespace = {
+        "CoreDatasource": SimpleNamespace,
+        "AssistantOutDsSchema": SimpleNamespace,
+        "DatasourceConf": DatasourceConf,
+        "json": json,
+        "aes_decrypt": lambda value: value,
+        "equals_ignore_case": lambda value, *options: (
+            value.lower() in [option.lower() for option in options]
+        ),
+        "pymysql": driver,
+        "PooledDB": pool,
+    }
+    exec(
+        compile(ast.Module(body=selected, type_ignores=[]), str(SOURCE), "exec"),
+        namespace,
+    )
+    return namespace["get_driver_connection"], connect, pool, driver
+
+
+def _datasource(datasource_type, ssl, extra_jdbc):
+    return SimpleNamespace(
+        type=datasource_type,
+        configuration=json.dumps(
+            {
+                "username": "test-user",
+                "password": "test-password",
+                "host": "test-host",
+                "port": 9030,
+                "database": "test-db",
+                "timeout": 30,
+                "ssl": ssl,
+                "poolSize": 8,
+                "extraJdbc": extra_jdbc,
+            }
+        ),
+    )
+
+
+def _connection_options(ssl):
+    options = {
+        "user": "test-user",
+        "passwd": "test-password",
+        "host": "test-host",
+        "port": 9030,
+        "db": "test-db",
+        "connect_timeout": 30,
+        "read_timeout": 30,
+    }
+    if ssl:
+        options["ssl"] = {"ssl_mode": "REQUIRE"}
+    return options
+
+
+@pytest.mark.parametrize("datasource_type", ["doris", "starrocks"])
+@pytest.mark.parametrize("ssl", [False, True])
+@pytest.mark.parametrize(
+    ("extra_jdbc", "db_config", "expected_extra"),
+    [
+        ("", {}, {}),
+        ("charset=utf8mb4", {}, {"charset": "utf8mb4"}),
+        (
+            "charset=latin1",
+            {"charset": "utf8mb4", "autocommit": True},
+            {"charset": "utf8mb4", "autocommit": True},
+        ),
+    ],
+    ids=["defaults", "extra-parameter", "config-override"],
+)
+def test_direct_connection_forwards_merged_parameters(
+    driver_connection, datasource_type, ssl, extra_jdbc, db_config, expected_extra
+):
+    get_connection, connect, pool, _ = driver_connection
+    datasource = _datasource(datasource_type, ssl, extra_jdbc)
+
+    connection = get_connection(datasource, db_config)
+
+    assert connection is connect.return_value
+    connect.assert_called_once_with(**(_connection_options(ssl) | expected_extra))
+    pool.assert_not_called()
+
+
+@pytest.mark.parametrize("datasource_type", ["doris", "starrocks"])
+@pytest.mark.parametrize("ssl", [False, True])
+def test_pooled_connection_preserves_parameters(
+    driver_connection, datasource_type, ssl
+):
+    get_connection, connect, pool, driver = driver_connection
+    datasource = _datasource(datasource_type, ssl, "charset=latin1")
+
+    connection = get_connection(
+        datasource, {"charset": "utf8mb4", "autocommit": True}, use_pool=True
+    )
+
+    assert connection is pool.return_value
+    pool.assert_called_once_with(
+        creator=driver,
+        **_connection_options(ssl),
+        charset="utf8mb4",
+        autocommit=True,
+        maxconnections=8,
+        mincached=5,
+        maxcached=10,
+        blocking=True,
+        maxusage=100,
+        ping=1,
+    )
+    connect.assert_not_called()