diff --git a/event_sink_clickhouse/settings/common.py b/event_sink_clickhouse/settings/common.py
index 73dae80..2ff6818 100644
--- a/event_sink_clickhouse/settings/common.py
+++ b/event_sink_clickhouse/settings/common.py
@@ -13,7 +13,7 @@ def plugin_settings(settings):
         # to avoid pulling in more dependencies to the platform than necessary.
         "url": "http://clickhouse:8123",
         "username": "ch_cms",
-        "password": "TYreGozgtDG3vkoWPUHVVM6q",
+        "password": "password",
         "database": "event_sink",
         "timeout_secs": 5,
     }
diff --git a/event_sink_clickhouse/sinks/base_sink.py b/event_sink_clickhouse/sinks/base_sink.py
index 94cf717..b66ad0c 100644
--- a/event_sink_clickhouse/sinks/base_sink.py
+++ b/event_sink_clickhouse/sinks/base_sink.py
@@ -288,13 +288,10 @@ def fetch_target_items(self, start_pk=None, ids=None, skip_ids=None, force_dump=
         skip_ids = (
             [str(item_id) for item_id in skip_ids] if skip_ids else []
         )
-        if batch_size:
-            paginator = Paginator(item_keys, batch_size)
-            for i in range(1, paginator.num_pages):
-                page = paginator.page(i)
-                yield from self.iter_target_items(page.object_list, skip_ids, force_dump)
-        else:
-            yield from self.iter_target_items(item_keys, skip_ids, force_dump)
+        paginator = Paginator(item_keys, batch_size)
+        for i in range(1, paginator.num_pages):
+            page = paginator.page(i)
+            yield from self.iter_target_items(page.object_list, skip_ids, force_dump)
 
     def iter_target_items(self, item_keys, skip_ids, force_dump):
         """
diff --git a/tests/test_base_sink.py b/tests/test_base_sink.py
index a215225..9c39158 100644
--- a/tests/test_base_sink.py
+++ b/tests/test_base_sink.py
@@ -25,6 +25,39 @@ class ChildSink(ModelBaseSink):  # pylint: disable=abstract-method
     serializer_class = Mock()
 
 
+@override_settings(
+    EVENT_SINK_CLICKHOUSE_BACKEND_CONFIG={
+        "url": "http://clickhouse:8123",
+        "username": "ch_cms",
+        "password": "password",
+        "database": "event_sink",
+        "timeout_secs": 5,
+    },
+    EVENT_SINK_CLICKHOUSE_MODEL_CONFIG={},
+)
+class TestBaseSink(TestCase):
+    """
+    Tests for the BaseSink.
+    """
+
+    def test_connection_overrides(self):
+        """
+        Test that connection_overrides() returns the correct data.
+        """
+        child_sink = ChildSink(connection_overrides={
+            "url": "http://dummy:8123",
+            "username": "dummy_username",
+            "password": "dummy_password",
+            "database": "dummy_database",
+            "timeout_secs": 0,
+        }, log=logging.getLogger())
+
+        self.assertEqual(child_sink.ch_url, "http://dummy:8123")
+        self.assertEqual(child_sink.ch_auth, ("dummy_username", "dummy_password"))
+        self.assertEqual(child_sink.ch_database, "dummy_database")
+        self.assertEqual(child_sink.ch_timeout_secs, 0)
+
+
 @override_settings(
     EVENT_SINK_CLICKHOUSE_BACKEND_CONFIG={
         # URL to a running ClickHouse server's HTTP interface. ex: https://foo.openedx.org:8443/ or
@@ -32,7 +65,7 @@ class ChildSink(ModelBaseSink):  # pylint: disable=abstract-method
         # to avoid pulling in more dependencies to the platform than necessary.
         "url": "http://clickhouse:8123",
         "username": "ch_cms",
-        "password": "TYreGozgtDG3vkoWPUHVVM6q",
+        "password": "password",
         "database": "event_sink",
         "timeout_secs": 5,
     },
@@ -243,3 +276,13 @@ def test_is_enabled(self):
         Test that is_enable() returns the correct data.
         """
         self.assertEqual(self.child_sink.is_enabled(), True)
+
+    def test_get_sink_by_model_name(self):
+        """
+        Test that get_sink_by_model_name() returns the correct data.
+        """
+        no_sink = ModelBaseSink.get_sink_by_model_name("non_existent_model")
+        child_sink = ModelBaseSink.get_sink_by_model_name("child_model")
+
+        self.assertIsNone(no_sink)
+        self.assertEqual(child_sink, ChildSink)