Move code behind feature flag

Puts the changes under the use_insert_all_in_internal_id feature flag

app/models/internal_id.rb

@@ -223,19 +223,33 @@ class InternalId < ApplicationRecord
     # If another process was faster in doing this, we'll end up with that record
     # when we do the lookup after the insert.
     def create_record
-      scope[:project].save! if scope[:project] && !scope[:project].persisted?
-      scope[:namespace].save! if scope[:namespace] && !scope[:namespace].persisted?
+      if Feature.enabled?(:use_insert_all_in_internal_id, default_enabled: :yaml)
+        scope[:project].save! if scope[:project] && !scope[:project].persisted?
+        scope[:namespace].save! if scope[:namespace] && !scope[:namespace].persisted?
 
-      attributes = {
-        project_id: scope[:project]&.id || scope[:project_id],
-        namespace_id: scope[:namespace]&.id || scope[:namespace_id],
-        usage: usage_value,
-        last_value: initial_value(subject, scope)
-      }
+        attributes = {
+          project_id: scope[:project]&.id || scope[:project_id],
+          namespace_id: scope[:namespace]&.id || scope[:namespace_id],
+          usage: usage_value,
+          last_value: initial_value(subject, scope)
+        }
 
-      InternalId.insert_all([attributes])
+        InternalId.insert_all([attributes])
 
-      lookup
+        lookup
+      else
+        begin
+          subject.transaction(requires_new: true) do
+            InternalId.create!(
+              **scope,
+              usage: usage_value,
+              last_value: initial_value(subject, scope)
+            )
+          end
+        rescue ActiveRecord::RecordNotUnique
+          lookup
+        end
+      end
     end
   end
 
@@ -330,21 +344,32 @@ class InternalId < ApplicationRecord
     end
 
     def create_record!(subject, scope, usage, value)
-      scope[:project].save! if scope[:project] && !scope[:project].persisted?
-      scope[:namespace].save! if scope[:namespace] && !scope[:namespace].persisted?
+      if Feature.enabled?(:use_insert_all_in_internal_id, default_enabled: :yaml)
+        scope[:project].save! if scope[:project] && !scope[:project].persisted?
+        scope[:namespace].save! if scope[:namespace] && !scope[:namespace].persisted?
 
-      attributes = {
-        project_id: scope[:project]&.id || scope[:project_id],
-        namespace_id: scope[:namespace]&.id || scope[:namespace_id],
-        usage: usage_value,
-        last_value: value
-      }
+        attributes = {
+          project_id: scope[:project]&.id || scope[:project_id],
+          namespace_id: scope[:namespace]&.id || scope[:namespace_id],
+          usage: usage_value,
+          last_value: value
+        }
 
-      result = InternalId.insert_all([attributes])
+        result = InternalId.insert_all([attributes])
 
-      raise RecordAlreadyExists if result.empty?
+        raise RecordAlreadyExists if result.empty?
 
-      value
+        value
+      else
+        begin
+          subject.transaction(requires_new: true) do
+            internal_id = InternalId.create!(**scope, usage: usage, last_value: value)
+            internal_id.last_value
+          end
+        rescue ActiveRecord::RecordNotUnique
+          raise RecordAlreadyExists
+        end
+      end
     end
 
     def arel_table

config/feature_flags/development/use_insert_all_in_internal_id.yml

+---
+name: use_insert_all_in_internal_id
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/68617
+rollout_issue_url: 
+milestone: '14.3'
+type: development
+group: group::project management
+default_enabled: false

spec/models/internal_id_spec.rb

@@ -238,20 +238,48 @@ RSpec.describe InternalId do
     end
   end
 
-  context 'when the feature flag is disabled' do
+  context 'when the explicit locking feature flag is disabled' do
     before do
       stub_feature_flags(generate_iids_without_explicit_locking: false)
     end
 
-    it_behaves_like 'a monotonically increasing id generator'
+    context 'when the insert all feature flag is enabled' do
+      before do
+        stub_feature_flags(use_insert_all_in_internal_id: true)
+      end
+
+      it_behaves_like 'a monotonically increasing id generator'
+    end
+
+    context 'when the insert all feature flag is disabled' do
+      before do
+        stub_feature_flags(use_insert_all_in_internal_id: false)
+      end
+
+      it_behaves_like 'a monotonically increasing id generator'
+    end
   end
 
-  context 'when the feature flag is enabled' do
+  context 'when the explicit locking feature flag is enabled' do
     before do
       stub_feature_flags(generate_iids_without_explicit_locking: true)
     end
 
-    it_behaves_like 'a monotonically increasing id generator'
+    context 'when the insert all feature flag is enabled' do
+      before do
+        stub_feature_flags(use_insert_all_in_internal_id: true)
+      end
+
+      it_behaves_like 'a monotonically increasing id generator'
+    end
+
+    context 'when the insert all feature flag is disabled' do
+      before do
+        stub_feature_flags(use_insert_all_in_internal_id: false)
+      end
+
+      it_behaves_like 'a monotonically increasing id generator'
+    end
   end
 
   describe '#increment_and_save!' do