Merge branch '328497-disable-lb-query-cache-in-non-request-contexts' into 'master'

Disable query cache when outside Rails executor

See merge request gitlab-org/gitlab!73814

lib/gitlab/database/load_balancing/load_balancer.rb

@@ -266,7 +266,10 @@ module Gitlab
         private
 
         def ensure_caching!
-          host.enable_query_cache! unless host.query_cache_enabled
+          return unless Rails.application.executor.active?
+          return if host.query_cache_enabled
+
+          host.enable_query_cache!
         end
 
         def request_cache

spec/lib/gitlab/database/load_balancing/load_balancer_spec.rb

@@ -89,6 +89,7 @@ RSpec.describe Gitlab::Database::LoadBalancing::LoadBalancer, :request_store do
       host = double(:host)
 
       allow(lb).to receive(:host).and_return(host)
+      allow(Rails.application.executor).to receive(:active?).and_return(true)
       allow(host).to receive(:query_cache_enabled).and_return(false)
       allow(host).to receive(:connection).and_return(connection)
 
@@ -97,6 +98,20 @@ RSpec.describe Gitlab::Database::LoadBalancing::LoadBalancer, :request_store do
       lb.read { 10 }
     end
 
+    it 'does not enable query cache when outside Rails executor context' do
+      connection = double(:connection)
+      host = double(:host)
+
+      allow(lb).to receive(:host).and_return(host)
+      allow(Rails.application.executor).to receive(:active?).and_return(false)
+      allow(host).to receive(:query_cache_enabled).and_return(false)
+      allow(host).to receive(:connection).and_return(connection)
+
+      expect(host).not_to receive(:enable_query_cache!)
+
+      lb.read { 10 }
+    end
+
     it 'marks hosts that are offline' do
       allow(lb).to receive(:connection_error?).and_return(true)