Apply 2 suggestion(s) to 2 file(s)

Co-authored-by: DANGER_GITLAB_API_TOKEN <project_278964_bot_445da1b60fc7336b6b6776383134d10f@noreply.gitlab.com>

config/feature_flags/gitlab_com_derisk/use_primary_and_secondary_stores_for_db_load_balancing.yml

+---
+name: use_primary_and_secondary_stores_for_db_load_balancing
+feature_issue_url: https://gitlab.com/gitlab-com/gl-infra/data-access/durability/team/-/issues/39
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/175822
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/509561
+milestone: '17.8'
+group: group::durability
+type: gitlab_com_derisk
+default_enabled: false

config/feature_flags/gitlab_com_derisk/use_primary_store_as_default_for_db_load_balancing.yml

+---
+name: use_primary_store_as_default_for_db_load_balancing
+feature_issue_url: https://gitlab.com/gitlab-com/gl-infra/data-access/durability/team/-/issues/39
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/175822
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/509562
+milestone: '17.8'
+group: group::durability
+type: gitlab_com_derisk
+default_enabled: false

lib/gitlab/redis.rb

@@ -10,6 +10,7 @@ module Redis
     ALL_CLASSES = [
       Gitlab::Redis::BufferedCounter,
       Gitlab::Redis::Cache,
+      Gitlab::Redis::ClusterDbLoadBalancing,
       Gitlab::Redis::DbLoadBalancing,
       Gitlab::Redis::FeatureFlag,
       *Gitlab::Redis::Queues.instances.values, # dynamically adds QueueShard* classes

lib/gitlab/redis/cluster_db_load_balancing.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Redis
+    class ClusterDbLoadBalancing < ::Gitlab::Redis::Wrapper
+      class << self
+        # The data we store on DbLoadBalancing used to be stored on SharedState.
+        def config_fallback
+          SharedState
+        end
+      end
+    end
+  end
+end

lib/gitlab/redis/db_load_balancing.rb

@@ -2,12 +2,16 @@
 
 module Gitlab
   module Redis
-    class DbLoadBalancing < ::Gitlab::Redis::Wrapper
+    class DbLoadBalancing < ::Gitlab::Redis::MultiStoreWrapper
       class << self
         # The data we store on DbLoadBalancing used to be stored on SharedState.
         def config_fallback
           SharedState
         end
+
+        def multistore
+          MultiStore.create_using_pool(ClusterDbLoadBalancing.pool, pool, store_name)
+        end
       end
     end
   end

spec/lib/gitlab/redis/cluster_db_load_balancing_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Redis::ClusterDbLoadBalancing, feature_category: :scalability do
+  include_examples "redis_new_instance_shared_examples", 'cluster_db_load_balancing', Gitlab::Redis::SharedState
+end

spec/lib/gitlab/redis/db_load_balancing_spec.rb

@@ -5,4 +5,10 @@
 RSpec.describe Gitlab::Redis::DbLoadBalancing, feature_category: :scalability do
   include_examples "redis_new_instance_shared_examples", 'db_load_balancing', Gitlab::Redis::SharedState
   include_examples "redis_shared_examples"
+  include_examples "multi_store_wrapper_shared_examples"
+
+  it 'migrates from self to ClusterDbLoadBalancing' do
+    expect(described_class.multistore.secondary_pool).to eq(described_class.pool)
+    expect(described_class.multistore.primary_pool).to eq(Gitlab::Redis::ClusterDbLoadBalancing.pool)
+  end
 end

spec/support/shared_examples/redis/multi_store_wrapper_shared_examples.rb

@@ -22,12 +22,6 @@
       end
     end
 
-    it 'borrows connection' do
-      described_class.with do |conn|
-        expect(Thread.current[conn.borrow_counter]).to eq(1)
-      end
-    end
-
     context 'when running on single-threaded runtime' do
       before do
         allow(Gitlab::Runtime).to receive(:multi_threaded?).and_return(false)