Optimizes issues_using_zoom_quick_actions query

By using batch count

app/models/zoom_meeting.rb

@@ -23,4 +23,10 @@ class ZoomMeeting < ApplicationRecord
   def self.canonical_meeting_url(issue)
     canonical_meeting(issue)&.url
   end
+
+  def self.distinct_count_by(column = nil, fallback = -1)
+    distinct.count(column)
+  rescue ActiveRecord::StatementInvalid
+    fallback
+  end
 end

lib/gitlab/usage_data.rb

@@ -85,7 +85,7 @@ module Gitlab
             issues: count(Issue),
             issues_created_from_gitlab_error_tracking_ui: count(SentryIssue),
             issues_with_associated_zoom_link: count(ZoomMeeting.added_to_issue),
-            issues_using_zoom_quick_actions: count(ZoomMeeting.select(:issue_id).distinct, batch: false),
+            issues_using_zoom_quick_actions: distinct_count(ZoomMeeting, :issue_id),
             issues_with_embedded_grafana_charts_approx: ::Gitlab::GrafanaEmbedUsageData.issue_count,
             incident_issues: count(::Issue.authored(::User.alert_bot)),
             keys: count(Key),

spec/models/zoom_meeting_spec.rb

@@ -151,4 +151,51 @@ describe ZoomMeeting do
       it_behaves_like 'can remove meetings'
     end
   end
+
+  describe '.distinct_count_by' do
+    let(:issue_1) { create(:issue) }
+    let(:issue_2) { create(:issue) }
+
+    context 'two meetings for the same issue' do
+      before do
+        create(:zoom_meeting, issue: issue_1)
+        create(:zoom_meeting, :removed_from_issue, issue: issue_1)
+      end
+
+      it 'returns a count of 1' do
+        expect(described_class.distinct_count_by(:issue_id)).to eq(1)
+      end
+
+      context 'when given no colum to count' do
+        it 'counts by :id and returns a count of 2' do
+          expect(described_class.distinct_count_by).to eq(2)
+        end
+      end
+    end
+
+    context 'one meeting for each issue' do
+      it 'returns a count of 2' do
+        create(:zoom_meeting, issue: issue_1)
+        create(:zoom_meeting, issue: issue_2)
+
+        expect(described_class.distinct_count_by(:issue_id)).to eq(2)
+      end
+    end
+
+    context 'the count query times out' do
+      before do
+        allow_next_instance_of(ActiveRecord::Relation) do |instance|
+          allow(instance).to receive(:count).and_raise(ActiveRecord::StatementInvalid.new(''))
+        end
+      end
+
+      it 'does not raise an error' do
+        expect { described_class.distinct_count_by(:issue_id) }.not_to raise_error
+      end
+
+      it 'returns -1' do
+        expect(described_class.distinct_count_by(:issue_id)).to eq(-1)
+      end
+    end
+  end
 end