Enable routable_two_step_lookup permanently

Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/30120

app/models/concerns/routable.rb

@@ -33,16 +33,9 @@ module Routable
     #
     # Returns a single object, or nil.
     def find_by_full_path(path, follow_redirects: false)
-      routable_calls_counter.increment(method: 'find_by_full_path')
-
-      if Feature.enabled?(:routable_two_step_lookup)
-        # Case sensitive match first (it's cheaper and the usual case)
-        # If we didn't have an exact match, we perform a case insensitive search
-        found = includes(:route).find_by(routes: { path: path }) || where_full_path_in([path]).take
-      else
-        order_sql = Arel.sql("(CASE WHEN routes.path = #{connection.quote(path)} THEN 0 ELSE 1 END)")
-        found = where_full_path_in([path]).reorder(order_sql).take
-      end
+      # Case sensitive match first (it's cheaper and the usual case)
+      # If we didn't have an exact match, we perform a case insensitive search
+      found = includes(:route).find_by(routes: { path: path }) || where_full_path_in([path]).take
 
       return found if found
 
@@ -61,19 +54,12 @@ module Routable
     def where_full_path_in(paths)
       return none if paths.empty?
 
-      routable_calls_counter.increment(method: 'where_full_path_in')
-
       wheres = paths.map do |path|
         "(LOWER(routes.path) = LOWER(#{connection.quote(path)}))"
       end
 
       includes(:route).where(wheres.join(' OR ')).references(:routes)
     end
-
-    # Temporary instrumentation of method calls
-    def routable_calls_counter
-      @routable_calls_counter ||= Gitlab::Metrics.counter(:gitlab_routable_calls_total, 'Number of calls to Routable by method')
-    end
   end
 
   def full_name

ee/changelogs/unreleased/ab-routable-two-step-lookup-remove-feature-flag.yml

+---
+title: Two step Routable lookup
+merge_request: 16621
+author:
+type: performance

spec/models/concerns/routable_spec.rb

@@ -58,7 +58,7 @@ describe Group, 'Routable' do
     end
   end
 
-  shared_examples_for '.find_by_full_path' do
+  context '.find_by_full_path' do
     let!(:nested_group) { create(:group, parent: group) }
 
     context 'without any redirect routes' do
@@ -117,24 +117,6 @@ describe Group, 'Routable' do
     end
   end
 
-  describe '.find_by_full_path' do
-    context 'with routable_two_step_lookup feature' do
-      before do
-        stub_feature_flags(routable_two_step_lookup: true)
-      end
-
-      it_behaves_like '.find_by_full_path'
-    end
-
-    context 'without routable_two_step_lookup feature' do
-      before do
-        stub_feature_flags(routable_two_step_lookup: false)
-      end
-
-      it_behaves_like '.find_by_full_path'
-    end
-  end
-
   describe '.where_full_path_in' do
     context 'without any paths' do
       it 'returns an empty relation' do