Using map to retrieve the element ids because of some issues with mysql

app/services/projects/batch_count_service.rb

+# Service class for getting and caching the number of elements of several projects
+# Warning: do not user this service with a really large set of projects
+# because the service use maps to retrieve the project ids.
 module Projects
   class BatchCountService
     def initialize(projects)
@@ -14,8 +17,6 @@ module Projects
     end
 
     def project_ids
-      return @projects if @projects.is_a?(ActiveRecord::Relation)
-
       @projects.map(&:id)
     end
 

app/services/projects/batch_forks_count_service.rb

+# Service class for getting and caching the number of forks of several projects
+# Warning: do not user this service with a really large set of projects
+# because the service use maps to retrieve the project ids
 module Projects
-  # Service class for getting and caching the number of forks of several projects
   class BatchForksCountService < Projects::BatchCountService
     def global_count
       @global_count ||= begin

app/services/projects/batch_open_issues_count_service.rb

+# Service class for getting and caching the number of issues of several projects
+# Warning: do not user this service with a really large set of projects
+# because the service use maps to retrieve the project ids
 module Projects
-  # Service class for getting and caching the number of forks of several projects
   class BatchOpenIssuesCountService < Projects::BatchCountService
     def global_count
       @global_count ||= begin