Merge branch '328519-fix-timeouts-when-paginating-issues-in-admin-panel' into 'master'

Improve pagination of users in admin panel

See merge request gitlab-org/gitlab!59884

app/controllers/admin/users_controller.rb

@@ -10,12 +10,15 @@ class Admin::UsersController < Admin::ApplicationController
 
   feature_category :users
 
+  PAGINATION_WITH_COUNT_LIMIT = 1000
+
   def index
     @users = User.filter_items(params[:filter]).order_name_asc
     @users = @users.search_with_secondary_emails(params[:search_query]) if params[:search_query].present?
     @users = users_with_included_associations(@users)
     @users = @users.sort_by_attribute(@sort = params[:sort])
     @users = @users.page(params[:page])
+    @users = @users.without_count if paginate_without_count?
 
     @cohorts = load_cohorts
 
@@ -228,6 +231,12 @@ class Admin::UsersController < Admin::ApplicationController
 
   protected
 
+  def paginate_without_count?
+    counts = Gitlab::Database::Count.approximate_counts([User])
+
+    counts[User] > PAGINATION_WITH_COUNT_LIMIT
+  end
+
   def users_with_included_associations(users)
     users.includes(:authorized_projects) # rubocop: disable CodeReuse/ActiveRecord
   end

app/views/admin/users/_users.html.haml

@@ -83,6 +83,6 @@
 
     = render partial: 'admin/users/user', collection: @users
 
-= paginate @users, theme: "gitlab"
+= paginate_collection @users
 
 = render partial: 'admin/users/modals'

changelogs/unreleased/328519-fix-timeouts-when-paginating-issues-in-admin-panel.yml

+---
+title: Improve pagination of users in the admin panel
+merge_request: 59884
+author:
+type: performance

spec/controllers/admin/users_controller_spec.rb

@@ -34,6 +34,29 @@ RSpec.describe Admin::UsersController do
       let(:target_id) { 'i_analytics_cohorts' }
       let(:request_params) { { tab: 'cohorts' } }
     end
+
+    context 'pagination' do
+      context 'when number of users is over the pagination limit' do
+        before do
+          stub_const('Admin::UsersController::PAGINATION_WITH_COUNT_LIMIT', 5)
+          allow(Gitlab::Database::Count).to receive(:approximate_counts).with([User]).and_return({ User => 6 })
+        end
+
+        it 'marks the relation for pagination without counts' do
+          get :index
+
+          expect(assigns(:users)).to be_a(Kaminari::PaginatableWithoutCount)
+        end
+      end
+
+      context 'when number of users is below the pagination limit' do
+        it 'marks the relation for pagination with counts' do
+          get :index
+
+          expect(assigns(:users)).not_to be_a(Kaminari::PaginatableWithoutCount)
+        end
+      end
+    end
   end
 
   describe 'GET :id' do