Revert move-recursive-ns-query-to-inner-join

This reverts commit ee1e606f, reversing
changes made to 6f95667d.

app/models/namespace.rb

@@ -261,13 +261,8 @@ class Namespace < ApplicationRecord
   # Includes projects from this namespace and projects from all subgroups
   # that belongs to this namespace
   def all_projects
-    return Project.where(namespace: self) if user?
-
-    if Feature.enabled?(:recursive_namespace_lookup_as_inner_join, self)
-      Project.joins("INNER JOIN (#{self_and_descendants.select(:id).to_sql}) namespaces ON namespaces.id=projects.namespace_id")
-    else
-      Project.where(namespace: self_and_descendants)
-    end
+    namespace = user? ? self : self_and_descendants
+    Project.where(namespace: namespace)
   end
 
   # Includes pipelines from this namespace and pipelines from all subgroups

changelogs/unreleased/revert-inner-join-cte-fix.yml

+---
+title: Remove the recursive_namespace_lookup_as_inner_join feature flag
+merge_request: 57131
+author:
+type: other

config/feature_flags/development/recursive_namespace_lookup_as_inner_join.yml

----
-name: recursive_namespace_lookup_as_inner_join
-introduced_by_url:
-rollout_issue_url:
-milestone: '13.10'
-type: development
-group: group::optimize
-default_enabled: false

ee/app/models/analytics/devops_adoption/segment.rb

@@ -13,12 +13,5 @@ class Analytics::DevopsAdoption::Segment < ApplicationRecord
 
   scope :ordered_by_name, -> { includes(:namespace).order('"namespaces"."name" ASC') }
   scope :for_namespaces, -> (namespaces) { where(namespace_id: namespaces) }
-  scope :for_parent, -> (namespace) {
-    if Feature.enabled?(:recursive_namespace_lookup_as_inner_join, namespace)
-      join_sql = namespace.self_and_descendants.to_sql
-      joins("INNER JOIN (#{join_sql}) namespaces ON namespaces.id=#{self.arel_table.name}.namespace_id")
-    else
-      for_namespaces(namespace.self_and_descendants)
-    end
-  }
+  scope :for_parent, -> (namespace) { for_namespaces(namespace.self_and_descendants) }
 end

ee/spec/models/analytics/devops_adoption/segment_spec.rb

@@ -52,10 +52,6 @@ RSpec.describe Analytics::DevopsAdoption::Segment, type: :model do
 
     subject(:segments) { described_class.for_parent(group) }
 
-    before do
-      stub_feature_flags(recursive_namespace_lookup_as_inner_join: true)
-    end
-
     it 'selects segments for given namespace only' do
       expect(segments).to match_array([segment1, segment2])
     end

spec/models/namespace_spec.rb

@@ -911,24 +911,10 @@ RSpec.describe Namespace do
       it { expect(namespace.all_projects.to_a).to match_array([project2, project1]) }
       it { expect(child.all_projects.to_a).to match_array([project2]) }
 
-      context 'when recursive_namespace_lookup_as_inner_join feature flag is on' do
-        before do
-          stub_feature_flags(recursive_namespace_lookup_as_inner_join: true)
-        end
-
-        it 'queries for the namespace and its descendants' do
-          expect(namespace.all_projects).to match_array([project1, project2])
-        end
-      end
+      it 'queries for the namespace and its descendants' do
+        expect(Project).to receive(:where).with(namespace: [namespace, child])
 
-      context 'when recursive_namespace_lookup_as_inner_join feature flag is off' do
-        before do
-          stub_feature_flags(recursive_namespace_lookup_as_inner_join: false)
-        end
-
-        it 'queries for the namespace and its descendants' do
-          expect(namespace.all_projects).to match_array([project1, project2])
-        end
+        namespace.all_projects
       end
     end