spec/lib/gitlab/database/count_spec.rb


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require 'spec_helper'

describe Gitlab::Database::Count do
  before do
    create_list(:project, 3)
    create(:identity)
  end

  let(:models) { [Project, Identity] }

  describe '.approximate_counts' do
    context 'with MySQL' do
      context 'when reltuples have not been updated' do
        it 'counts all models the normal way' do
          expect(Gitlab::Database).to receive(:postgresql?).and_return(false)

          expect(Project).to receive(:count).and_call_original
          expect(Identity).to receive(:count).and_call_original

          expect(described_class.approximate_counts(models)).to eq({ Project => 3, Identity => 1 })
        end
      end
    end

    context 'with PostgreSQL', :postgresql do
      let(:reltuples_strategy) { double('reltuples_strategy', count: {}) }

      before do
        allow(Gitlab::Database::Count::ReltuplesCountStrategy).to receive(:new).with(models).and_return(reltuples_strategy)
      end

      describe 'when reltuples have not been updated' do
        it 'counts all models the normal way' do
          expect(Project).to receive(:count).and_call_original
          expect(Identity).to receive(:count).and_call_original
          expect(described_class.approximate_counts(models)).to eq({ Project => 3, Identity => 1 })
        end
      end

      describe 'no permission' do
        it 'falls back to standard query' do
          allow(ActiveRecord::Base).to receive(:transaction).and_raise(PG::InsufficientPrivilege)

          expect(Project).to receive(:count).and_call_original
          expect(Identity).to receive(:count).and_call_original
          expect(described_class.approximate_counts(models)).to eq({ Project => 3, Identity => 1 })
        end
      end

      describe 'when some reltuples have been updated' do
        it 'counts projects in the fast way' do
          expect(reltuples_strategy).to receive(:count).and_return({ Project => 3 })

          expect(Project).not_to receive(:count).and_call_original
          expect(Identity).to receive(:count).and_call_original
          expect(described_class.approximate_counts(models)).to eq({ Project => 3, Identity => 1 })
        end
      end

      # TODO: This covers two parts: reltuple strategy itself and the fallback
      # TODO: Add spec that covers strategy details for reltuple strategy
      describe 'when all reltuples have been updated' do
        #before do
          #ActiveRecord::Base.connection.execute('ANALYZE projects')
          #ActiveRecord::Base.connection.execute('ANALYZE identities')
        #end

        it 'counts models with the standard way' do
          allow(reltuples_strategy).to receive(:count).and_return({ Project => 3, Identity => 1 })
          expect(Project).not_to receive(:count)
          expect(Identity).not_to receive(:count)

          expect(described_class.approximate_counts(models)).to eq({ Project => 3, Identity => 1 })
        end
      end

      describe Gitlab::Database::Count::ExactCountStrategy do
        subject { described_class.new(models).count }

        it 'counts all models' do
          models.each { |model| expect(model).to receive(:count).and_call_original }

          expect(subject).to eq({ Project => 3, Identity => 1 })
        end
      end
    end
  end
end