Remove legacy finder for projects updated recently

This commit removes the legacy queries for projects updated
recently since  we made Foreign Data Wrapper (FDW) a hard
requirement for Geo on GitLab 12.0.

ee/app/finders/geo/legacy_project_updated_recently_finder.rb

-# frozen_string_literal: true
-
-# Finder for retrieving projects updated recently that
-# belong to a specific shard using cross-database joins.
-#
-# Basic usage:
-#
-#     Geo::LegacyProjectUpdatedRecentlyFinder
-#       .new(current_node: Gitlab::Geo.current_node, shard_name: 'default', batch_size: 1000)
-#       .execute
-module Geo
-  class LegacyProjectUpdatedRecentlyFinder < RegistryFinder
-    def initialize(current_node: nil, shard_name:, batch_size:)
-      super(current_node: current_node)
-      @shard_name = shard_name
-      @batch_size = batch_size
-    end
-
-    # rubocop:disable CodeReuse/ActiveRecord
-    def execute
-      registries = find_registries_to_resync
-      return Project.none if registries.empty?
-
-      id_and_last_sync_values = registries.map do |id, last_repository_synced_at|
-        "(#{id}, #{quote_value(last_repository_synced_at)})"
-      end
-
-      projects = current_node.projects.within_shards(shard_name)
-
-      joined_relation = projects.joins(<<~SQL)
-        INNER JOIN
-        (VALUES #{id_and_last_sync_values.join(',')})
-        project_registry(id, last_repository_synced_at)
-        ON #{Project.table_name}.id = project_registry.id
-      SQL
-
-      joined_relation
-        .limit(batch_size)
-    end
-    # rubocop:enable CodeReuse/ActiveRecord
-
-    private
-
-    attr_reader :batch_size, :shard_name
-
-    # rubocop:disable CodeReuse/ActiveRecord
-    def find_registries_to_resync
-      Geo::ProjectRegistry
-        .dirty
-        .retry_due
-        .pluck(:project_id, :last_repository_synced_at)
-    end
-    # rubocop:enable CodeReuse/ActiveRecord
-  end
-end

ee/app/finders/geo/project_registry_finder.rb

@@ -79,21 +79,13 @@ module Geo
     end
 
     def find_projects_updated_recently(shard_name:, batch_size:)
-      finder_klass_for_projects_updated_recently
+      Geo::ProjectUpdatedRecentlyFinder
         .new(current_node: current_node, shard_name: shard_name, batch_size: batch_size)
         .execute
     end
 
     private
 
-    def finder_klass_for_projects_updated_recently
-      if use_legacy_queries_for_selective_sync?
-        Geo::LegacyProjectUpdatedRecentlyFinder
-      else
-        Geo::ProjectUpdatedRecentlyFinder
-      end
-    end
-
     def registries_for_synced_projects(type)
       Geo::ProjectRegistrySyncedFinder
         .new(current_node: current_node, type: type)

ee/spec/finders/geo/legacy_project_updated_recently_finder_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-
-describe Geo::LegacyProjectUpdatedRecentlyFinder, :geo do
-  describe '#execute' do
-    let(:node) { create(:geo_node) }
-    let(:group_1) { create(:group) }
-    let(:group_2) { create(:group) }
-    let(:nested_group_1) { create(:group, parent: group_1) }
-    let!(:project_1) { create(:project, group: group_1) }
-    let!(:project_2) { create(:project, group: nested_group_1) }
-    let!(:project_3) { create(:project, group: group_2) }
-    let!(:project_4) { create(:project, group: group_1) }
-
-    before do
-      project_4.update_column(:repository_storage, 'foo')
-
-      create(:geo_project_registry, :synced, :repository_dirty, project: project_1)
-      create(:geo_project_registry, :synced, :repository_dirty, project: project_2)
-      create(:geo_project_registry, :synced, project: project_3)
-      create(:geo_project_registry, :synced, :wiki_dirty, project: project_4)
-    end
-
-    subject { described_class.new(current_node: node, shard_name: 'default', batch_size: 100) }
-
-    context 'without selective sync' do
-      it 'returns projects with a dirty entry on the tracking database' do
-        expect(subject.execute).to match_ids(project_1, project_2)
-      end
-    end
-
-    context 'with selective sync by namespace' do
-      it 'returns projects that belong to the namespaces with a dirty entry on the tracking database' do
-        node.update!(selective_sync_type: 'namespaces', namespaces: [group_1])
-
-        expect(subject.execute).to match_ids(project_1, project_2)
-      end
-    end
-
-    context 'with selective sync by shard' do
-      before do
-        node.update!(selective_sync_type: 'shards', selective_sync_shards: ['foo'])
-      end
-
-      it 'does not return registries when selected shards to sync does not include the shard_name' do
-        subject = described_class.new(current_node: node, shard_name: 'default', batch_size: 100)
-
-        expect(subject.execute).to be_empty
-      end
-
-      it 'returns projects that belong to the shards with a dirty entry on the tracking database' do
-        project_5 = create(:project, group: group_1)
-        project_5.update_column(:repository_storage, 'foo')
-        create(:geo_project_registry, :synced, project: project_5)
-
-        subject = described_class.new(current_node: node, shard_name: 'foo', batch_size: 100)
-
-        expect(subject.execute).to match_ids(project_4)
-      end
-    end
-  end
-end

ee/spec/finders/geo/project_registry_finder_spec.rb

 require 'spec_helper'
 
 describe Geo::ProjectRegistryFinder, :geo do
-  using RSpec::Parameterized::TableSyntax
-
   include ::EE::GeoHelpers
 
   # Using let() instead of set() because set() does not work properly
@@ -380,35 +378,6 @@ describe Geo::ProjectRegistryFinder, :geo do
     end
   end
 
-  shared_examples 'delegates to the proper finder' do |legacy_finder_klass, finder_klass, method, args|
-    where(:selective_sync, :fdw_enabled, :fdw_for_selective_sync, :finder) do
-      false | false | false | legacy_finder_klass
-      false | false | true  | legacy_finder_klass
-      false | true  | true  | finder_klass
-      false | true  | false | finder_klass
-      true  | false | false | legacy_finder_klass
-      true  | false | true  | legacy_finder_klass
-      true  | true  | true  | finder_klass
-      true  | true  | false | legacy_finder_klass
-    end
-
-    with_them do
-      before do
-        stub_fdw(fdw_enabled)
-        stub_feature_flags(use_fdw_queries_for_selective_sync: fdw_for_selective_sync)
-        stub_selective_sync(secondary, selective_sync)
-      end
-
-      it 'delegates to the proper finder' do
-        expect_next_instance_of(finder) do |finder|
-          expect(finder).to receive(:execute).once
-        end
-
-        subject.public_send(method, *args)
-      end
-    end
-  end
-
   context 'FDW', :geo_fdw do
     context 'with use_fdw_queries_for_selective_sync disabled' do
       before do
@@ -438,10 +407,13 @@ describe Geo::ProjectRegistryFinder, :geo do
   end
 
   describe '#find_projects_updated_recently', :geo_fdw do
-    include_examples 'delegates to the proper finder',
-      Geo::LegacyProjectUpdatedRecentlyFinder,
-      Geo::ProjectUpdatedRecentlyFinder,
-      :find_projects_updated_recently, [shard_name: 'default', batch_size: 100]
+    it 'delegates to the proper finder' do
+      expect_next_instance_of(Geo::ProjectUpdatedRecentlyFinder) do |finder|
+        expect(finder).to receive(:execute).once
+      end
+
+      subject.find_projects_updated_recently(shard_name: 'default', batch_size: 100)
+    end
   end
 
   describe '#find_failed_project_registries', :geo_fdw do