Does not update repository statistics on a read-only instance

GitGarbageCollectWorker may be run on a Geo secondary

app/workers/git_garbage_collect_worker.rb

@@ -37,10 +37,7 @@ class GitGarbageCollectWorker # rubocop:disable Scalability/IdempotentWorker
     # Refresh the branch cache in case garbage collection caused a ref lookup to fail
     flush_ref_caches(project) if task == :gc
 
-    if task != :pack_refs
-      project.repository.expire_statistics_caches
-      Projects::UpdateStatisticsService.new(project, nil, statistics: [:repository_size, :lfs_objects_size]).execute
-    end
+    update_repository_statistics(project) if task != :pack_refs
 
     # In case pack files are deleted, release libgit2 cache and open file
     # descriptors ASAP instead of waiting for Ruby garbage collection
@@ -106,6 +103,13 @@ class GitGarbageCollectWorker # rubocop:disable Scalability/IdempotentWorker
     project.repository.has_visible_content?
   end
 
+  def update_repository_statistics(project)
+    project.repository.expire_statistics_caches
+    return if Gitlab::Database.read_only? # GitGarbageCollectWorker may be run on a Geo secondary
+
+    Projects::UpdateStatisticsService.new(project, nil, statistics: [:repository_size, :lfs_objects_size]).execute
+  end
+
   def bitmaps_enabled?
     Gitlab::CurrentSettings.housekeeping_bitmaps_enabled
   end

spec/workers/git_garbage_collect_worker_spec.rb

@@ -25,12 +25,18 @@ RSpec.describe GitGarbageCollectWorker do
   end
 
   shared_examples 'it updates the project statistics' do
-    specify do
-      expect_any_instance_of(Projects::UpdateStatisticsService).to receive(:execute).and_call_original
-      expect(Projects::UpdateStatisticsService)
-        .to receive(:new)
-        .with(project, nil, statistics: [:repository_size, :lfs_objects_size])
-        .and_call_original
+    it 'updates the project statistics' do
+      expect_next_instance_of(Projects::UpdateStatisticsService, project, nil, statistics: [:repository_size, :lfs_objects_size]) do |service|
+        expect(service).to receive(:execute).and_call_original
+      end
+
+      subject.perform(*params)
+    end
+
+    it 'does nothing if the database is read-only' do
+      allow(Gitlab::Database).to receive(:read_only?) { true }
+
+      expect_any_instance_of(Projects::UpdateStatisticsService).not_to receive(:execute)
 
       subject.perform(*params)
     end
@@ -141,7 +147,8 @@ RSpec.describe GitGarbageCollectWorker do
             end
 
             it 'does nothing if the database is read-only' do
-              expect(Gitlab::Database).to receive(:read_only?) { true }
+              allow(Gitlab::Database).to receive(:read_only?) { true }
+
               expect_any_instance_of(Gitlab::Cleanup::OrphanLfsFileReferences).not_to receive(:run!)
 
               subject.perform(*params)