Does not refresh snippet statistics on read-only instance

SnippetStatistics#refresh! may be run on a Geo secondary

app/models/snippet_statistics.rb

@@ -34,6 +34,8 @@ class SnippetStatistics < ApplicationRecord
   end
 
   def refresh!
+    return if Gitlab::Database.read_only?
+
     update_commit_count
     update_repository_size
     update_file_count

spec/models/snippet_statistics_spec.rb

@@ -75,15 +75,28 @@ RSpec.describe SnippetStatistics do
   end
 
   describe '#refresh!' do
-    subject { statistics.refresh! }
-
     it 'retrieves and saves statistic data from repository' do
       expect(statistics).to receive(:update_commit_count)
       expect(statistics).to receive(:update_file_count)
       expect(statistics).to receive(:update_repository_size)
       expect(statistics).to receive(:save!)
 
-      subject
+      statistics.refresh!
+    end
+
+    context 'when the database is read-only' do
+      it 'does nothing' do
+        allow(Gitlab::Database).to receive(:read_only?) { true }
+
+        expect(statistics).not_to receive(:update_commit_count)
+        expect(statistics).not_to receive(:update_file_count)
+        expect(statistics).not_to receive(:update_repository_size)
+        expect(statistics).not_to receive(:save!)
+        expect(Namespaces::ScheduleAggregationWorker)
+          .not_to receive(:perform_async)
+
+        statistics.refresh!
+      end
     end
   end