Includes logic to persist namespace statistics

- Add two new ActiveRecord models:
  - RootNamespaceStoragestatistics will persist root namespace statistics
  - NamespaceAggregationSchedule will save information when a new update
to the namespace statistics needs to be scheduled
- Inject into UpdateProjectStatistics concern a new callback that will
call an async job to insert a new row onto NamespaceAggregationSchedule
table
- When a new row is inserted a new job is scheduled. This job will
update call an specific service to update the statistics and after that
it will delete thee aggregated scheduled row
- The RefresherServices makes heavy use of arel to build composable
queries to update Namespace::RootStorageStatistics attributes.
- Add an extra worker to traverse pending rows on
NAmespace::AggregationSchedule table and schedule a worker for each one
of this rows.
- Add an extra worker to traverse pending rows on
NAmespace::AggregationSchedule table and schedule a worker for each one
of this rows

1 files changed, 87 insertions, 3 deletions

diff --git a/spec/support/shared_examples/models/update_project_statistics_shared_examples.rb b/spec/support/shared_examples/models/update_project_statistics_shared_examples.rb
index 1b09c3dd636..aad63982e7a 100644
--- a/spec/support/shared_examples/models/update_project_statistics_shared_examples.rb
+++ b/spec/support/shared_examples/models/update_project_statistics_shared_examples.rb
@@ -25,16 +25,36 @@ shared_examples_for 'UpdateProjectStatistics' do
         .to change { reload_stat }
         .by(delta)
     end
+
+    it 'schedules a namespace statistics worker' do
+      expect(Namespaces::ScheduleAggregationWorker)
+        .to receive(:perform_async).once
+
+      subject.save!
+    end
+
+    context 'when feature flag is disabled for the namespace' do
+      it 'does not schedules a namespace statistics worker' do
+        namespace = subject.project.root_ancestor
+
+        stub_feature_flags(update_statistics_namespace: false, namespace: namespace)
+
+        expect(Namespaces::ScheduleAggregationWorker)
+          .not_to receive(:perform_async)
+
+        subject.save!
+      end
+    end
   end
 
   context 'when updating' do
+    let(:delta) { 42 }
+
     before do
       subject.save!
     end
 
     it 'updates project statistics' do
-      delta = 42
-
       expect(ProjectStatistics)
         .to receive(:increment_statistic)
         .and_call_original
@@ -45,6 +65,42 @@ shared_examples_for 'UpdateProjectStatistics' do
         .to change { reload_stat }
         .by(delta)
     end
+
+    it 'schedules a namespace statistics worker' do
+      expect(Namespaces::ScheduleAggregationWorker)
+        .to receive(:perform_async).once
+
+      subject.write_attribute(statistic_attribute, read_attribute + delta)
+      subject.save!
+    end
+
+    it 'avoids N + 1 queries' do
+      subject.write_attribute(statistic_attribute, read_attribute + delta)
+
+      control_count = ActiveRecord::QueryRecorder.new do
+        subject.save!
+      end
+
+      subject.write_attribute(statistic_attribute, read_attribute + delta)
+
+      expect do
+        subject.save!
+      end.not_to exceed_query_limit(control_count)
+    end
+
+    context 'when the feature flag is disabled for the namespace' do
+      it 'does not schedule a namespace statistics worker' do
+        namespace = subject.project.root_ancestor
+
+        stub_feature_flags(update_statistics_namespace: false, namespace: namespace)
+
+        expect(Namespaces::ScheduleAggregationWorker)
+          .not_to receive(:perform_async)
+
+        subject.write_attribute(statistic_attribute, read_attribute + delta)
+        subject.save!
+      end
+    end
   end
 
   context 'when destroying' do
@@ -59,11 +115,18 @@ shared_examples_for 'UpdateProjectStatistics' do
         .to receive(:increment_statistic)
         .and_call_original
 
-      expect { subject.destroy }
+      expect { subject.destroy! }
         .to change { reload_stat }
         .by(delta)
     end
 
+    it 'schedules a namespace statistics worker' do
+      expect(Namespaces::ScheduleAggregationWorker)
+        .to receive(:perform_async).once
+
+      subject.destroy!
+    end
+
     context 'when it is destroyed from the project level' do
       it 'does not update the project statistics' do
         expect(ProjectStatistics)
@@ -72,6 +135,27 @@ shared_examples_for 'UpdateProjectStatistics' do
         project.update(pending_delete: true)
         project.destroy!
       end
+
+      it 'does not schedule a namespace statistics worker' do
+        expect(Namespaces::ScheduleAggregationWorker)
+          .not_to receive(:perform_async)
+
+        project.update(pending_delete: true)
+        project.destroy!
+      end
+    end
+
+    context 'when feature flag is disabled for the namespace' do
+      it 'does not schedule a namespace statistics worker' do
+        namespace = subject.project.root_ancestor
+
+        stub_feature_flags(update_statistics_namespace: false, namespace: namespace)
+
+        expect(Namespaces::ScheduleAggregationWorker)
+          .not_to receive(:perform_async)
+
+        subject.destroy!
+      end
     end
   end
 end