Throttle the number of UPDATEs triggered by touch

This throttles the number of UPDATE queries that can be triggered by
calling "touch" on a Note, Issue, or MergeRequest. For Note objects we
also take care of updating the associated "noteable" relation in a
smarter way than Rails does by default.

5 files changed, 30 insertions, 2 deletions

diff --git a/spec/models/concerns/issuable_spec.rb b/spec/models/concerns/issuable_spec.rb
index a53b59c4e08..9df26f06a11 100644
--- a/spec/models/concerns/issuable_spec.rb
+++ b/spec/models/concerns/issuable_spec.rb
@@ -171,7 +171,7 @@ describe Issuable do
 
     it "returns false when record has been updated" do
       allow(issue).to receive(:today?).and_return(true)
-      issue.touch
+      issue.update_attribute(:updated_at, 1.hour.ago)
       expect(issue.new?).to be_falsey
     end
   end
diff --git a/spec/models/issue_spec.rb b/spec/models/issue_spec.rb
index 5f901262598..0ea287d007a 100644
--- a/spec/models/issue_spec.rb
+++ b/spec/models/issue_spec.rb
@@ -765,4 +765,8 @@ describe Issue do
       expect(described_class.public_only).to eq([public_issue])
     end
   end
+
+  it_behaves_like 'throttled touch' do
+    subject { create(:issue, updated_at: 1.hour.ago) }
+  end
 end
diff --git a/spec/models/merge_request_spec.rb b/spec/models/merge_request_spec.rb
index e606fb027b5..71fbb82184c 100644
--- a/spec/models/merge_request_spec.rb
+++ b/spec/models/merge_request_spec.rb
@@ -1851,4 +1851,8 @@ describe MergeRequest do
         .to change { project.open_merge_requests_count }.from(1).to(0)
     end
   end
+
+  it_behaves_like 'throttled touch' do
+    subject { create(:merge_request, updated_at: 1.hour.ago) }
+  end
 end
diff --git a/spec/models/note_spec.rb b/spec/models/note_spec.rb
index 6e7e8c4c570..e1a0c55b6a6 100644
--- a/spec/models/note_spec.rb
+++ b/spec/models/note_spec.rb
@@ -5,7 +5,7 @@ describe Note do
 
   describe 'associations' do
     it { is_expected.to belong_to(:project) }
-    it { is_expected.to belong_to(:noteable).touch(true) }
+    it { is_expected.to belong_to(:noteable).touch(false) }
     it { is_expected.to belong_to(:author).class_name('User') }
 
     it { is_expected.to have_many(:todos).dependent(:destroy) }
diff --git a/spec/support/shared_examples/throttled_touch.rb b/spec/support/shared_examples/throttled_touch.rb
new file mode 100644
index 00000000000..4a25bb9b750
--- /dev/null
+++ b/spec/support/shared_examples/throttled_touch.rb
@@ -0,0 +1,20 @@
+shared_examples_for 'throttled touch' do
+  describe '#touch' do
+    it 'updates the updated_at timestamp' do
+      Timecop.freeze do
+        subject.touch
+        expect(subject.updated_at).to eq(Time.zone.now)
+      end
+    end
+
+    it 'updates the object at most once per minute' do
+      first_updated_at = Time.zone.now - (ThrottledTouch::TOUCH_INTERVAL * 2)
+      second_updated_at = Time.zone.now - (ThrottledTouch::TOUCH_INTERVAL * 1.5)
+
+      Timecop.freeze(first_updated_at) { subject.touch }
+      Timecop.freeze(second_updated_at) { subject.touch }
+
+      expect(subject.updated_at).to eq(first_updated_at)
+    end
+  end
+end