Disabled SCH in MultiDBClient underlying clients (#3938)

* Disabled SCH in MultiDBClient underlying clients

* Fixed comment format

* Codestyle fixes

* Codestyle fixes

* Allow user to override maint_notifications_config

* Codestyle fixes

---------

Co-authored-by: petyaslavova <petya.slavova@redis.com>

Author: vladvildanov

redis/multidb/client.py

@@ -8,6 +8,7 @@
 from redis.backoff import NoBackoff
 from redis.client import PubSubWorkerThread
 from redis.commands import CoreCommands, RedisModuleCommands
+from redis.maint_notifications import MaintNotificationsConfig
 from redis.multidb.circuit import CircuitBreaker
 from redis.multidb.circuit import State as CBState
 from redis.multidb.command_executor import DefaultCommandExecutor
@@ -149,7 +150,14 @@ def add_database(self, config: DatabaseConfig, skip_unhealthy: bool = True):
         """
         # The retry object is not used in the lower level clients, so we can safely remove it.
         # We rely on command_retry in terms of global retries.
-        config.client_kwargs.update({"retry": Retry(retries=0, backoff=NoBackoff())})
+        config.client_kwargs["retry"] = Retry(retries=0, backoff=NoBackoff())
+
+        # Maintenance notifications are disabled by default in underlying clients,
+        # but user can override this by providing their own config.
+        if "maint_notifications_config" not in config.client_kwargs:
+            config.client_kwargs["maint_notifications_config"] = (
+                MaintNotificationsConfig(enabled=False)
+            )
 
         if config.from_url:
             client = self._config.client_class.from_url(

redis/multidb/config.py

@@ -9,6 +9,7 @@
 from redis.backoff import ExponentialWithJitterBackoff, NoBackoff
 from redis.data_structure import WeightedList
 from redis.event import EventDispatcher, EventDispatcherInterface
+from redis.maint_notifications import MaintNotificationsConfig
 from redis.multidb.circuit import (
     DEFAULT_GRACE_PERIOD,
     CircuitBreaker,
@@ -164,10 +165,17 @@ def databases(self) -> Databases:
         for database_config in self.databases_config:
             # The retry object is not used in the lower level clients, so we can safely remove it.
             # We rely on command_retry in terms of global retries.
-            database_config.client_kwargs.update(
-                {"retry": Retry(retries=0, backoff=NoBackoff())}
+            database_config.client_kwargs["retry"] = Retry(
+                retries=0, backoff=NoBackoff()
             )
 
+            # Maintenance notifications are disabled by default in underlying clients,
+            # but user can override this by providing their own config.
+            if "maint_notifications_config" not in database_config.client_kwargs:
+                database_config.client_kwargs["maint_notifications_config"] = (
+                    MaintNotificationsConfig(enabled=False)
+                )
+
             if database_config.from_url:
                 client = self.client_class.from_url(
                     database_config.from_url, **database_config.client_kwargs

tests/test_multidb/test_config.py

@@ -3,6 +3,7 @@
 import pytest
 
 from redis.connection import ConnectionPool
+from redis.maint_notifications import MaintNotificationsConfig
 from redis.multidb.circuit import (
     PBCircuitBreakerAdapter,
     CircuitBreaker,
@@ -134,6 +135,66 @@ def test_overridden_config(self):
         assert config.failover_strategy == mock_failover_strategy
         assert config.auto_fallback_interval == auto_fallback_interval
 
+    def test_underlying_clients_have_disabled_retry_and_maint_notifications(self):
+        """
+        Test that underlying clients have retry disabled (0 retries)
+        and maintenance notifications disabled.
+        """
+        db_configs = [
+            DatabaseConfig(
+                client_kwargs={"host": "host1", "port": "port1"},
+                weight=1.0,
+            ),
+            DatabaseConfig(
+                client_kwargs={"host": "host2", "port": "port2"},
+                weight=0.9,
+            ),
+        ]
+
+        config = MultiDbConfig(databases_config=db_configs)
+        databases = config.databases()
+
+        assert len(databases) == 2
+
+        for db, weight in databases:
+            # Verify retry is disabled (0 retries)
+            retry = db.client.get_retry()
+            assert retry is not None
+            assert retry.get_retries() == 0
+
+            # Verify maint_notifications_config is disabled
+            # When maint_notifications_config.enabled is False, the pool handler is None
+            pool = db.client.connection_pool
+            assert pool._maint_notifications_pool_handler is None
+
+    def test_user_provided_maint_notifications_config_is_respected(self):
+        """
+        Test that user-provided maint_notifications_config is not overwritten.
+        """
+        user_maint_config = MaintNotificationsConfig(enabled=True)
+        db_configs = [
+            DatabaseConfig(
+                client_kwargs={
+                    "host": "host1",
+                    "port": "port1",
+                    "protocol": 3,  # Required for maint notifications
+                    "maint_notifications_config": user_maint_config,
+                },
+                weight=1.0,
+            ),
+        ]
+
+        config = MultiDbConfig(databases_config=db_configs)
+        databases = config.databases()
+
+        assert len(databases) == 1
+
+        db, weight = databases[0]
+        # Verify user-provided maint_notifications_config is respected
+        pool = db.client.connection_pool
+        assert pool._maint_notifications_pool_handler is not None
+        assert pool._maint_notifications_pool_handler.config.enabled is True
+
 
 @pytest.mark.onlynoncluster
 class TestDatabaseConfig: