1 files changed, 78 insertions, 0 deletions
diff --git a/lib/gitlab/background_migration/cleanup_orphaned_lfs_objects_projects.rb b/lib/gitlab/background_migration/cleanup_orphaned_lfs_objects_projects.rb
new file mode 100644
index 00000000000..cb9b0e88ef4
--- /dev/null
+++ b/lib/gitlab/background_migration/cleanup_orphaned_lfs_objects_projects.rb
@@ -0,0 +1,78 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module BackgroundMigration
+    # The migration is used to cleanup orphaned lfs_objects_projects in order to
+    # introduce valid foreign keys to this table
+    class CleanupOrphanedLfsObjectsProjects
+      # A model to access lfs_objects_projects table in migrations
+      class LfsObjectsProject < ActiveRecord::Base
+        self.table_name = 'lfs_objects_projects'
+
+        include ::EachBatch
+
+        belongs_to :lfs_object
+        belongs_to :project
+      end
+
+      # A model to access lfs_objects table in migrations
+      class LfsObject < ActiveRecord::Base
+        self.table_name = 'lfs_objects'
+      end
+
+      # A model to access projects table in migrations
+      class Project < ActiveRecord::Base
+        self.table_name = 'projects'
+      end
+
+      SUB_BATCH_SIZE = 5000
+      CLEAR_CACHE_DELAY = 1.minute
+
+      def perform(start_id, end_id)
+        cleanup_lfs_objects_projects_without_lfs_object(start_id, end_id)
+        cleanup_lfs_objects_projects_without_project(start_id, end_id)
+      end
+
+      private
+
+      def cleanup_lfs_objects_projects_without_lfs_object(start_id, end_id)
+        each_record_without_association(start_id, end_id, :lfs_object, :lfs_objects) do |lfs_objects_projects_without_lfs_objects|
+          projects = Project.where(id: lfs_objects_projects_without_lfs_objects.select(:project_id))
+
+          if projects.present?
+            ProjectCacheWorker.bulk_perform_in_with_contexts(
+              CLEAR_CACHE_DELAY,
+              projects,
+              arguments_proc: ->(project) { [project.id, [], [:lfs_objects_size]] },
+              context_proc: ->(project) { { project: project } }
+            )
+          end
+
+          lfs_objects_projects_without_lfs_objects.delete_all
+        end
+      end
+
+      def cleanup_lfs_objects_projects_without_project(start_id, end_id)
+        each_record_without_association(start_id, end_id, :project, :projects) do |lfs_objects_projects_without_projects|
+          lfs_objects_projects_without_projects.delete_all
+        end
+      end
+
+      def each_record_without_association(start_id, end_id, association, table_name)
+        batch = LfsObjectsProject.where(id: start_id..end_id)
+
+        batch.each_batch(of: SUB_BATCH_SIZE) do |sub_batch|
+          first, last = sub_batch.pluck(Arel.sql('min(lfs_objects_projects.id), max(lfs_objects_projects.id)')).first
+
+          lfs_objects_without_association =
+            LfsObjectsProject
+              .unscoped
+              .left_outer_joins(association)
+              .where(id: (first..last), table_name => { id: nil })
+
+          yield lfs_objects_without_association
+        end
+      end
+    end
+  end
+end