1 files changed, 31 insertions, 0 deletions
diff --git a/lib/gitlab/background_migration/remove_project_group_link_with_missing_groups.rb b/lib/gitlab/background_migration/remove_project_group_link_with_missing_groups.rb
new file mode 100644
index 00000000000..879e52c96bf
--- /dev/null
+++ b/lib/gitlab/background_migration/remove_project_group_link_with_missing_groups.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module BackgroundMigration
+    # A job to remove `project_group_links` records whose associated group
+    # does not exist in `namespaces` table anymore.
+    class RemoveProjectGroupLinkWithMissingGroups < Gitlab::BackgroundMigration::BatchedMigrationJob
+      scope_to ->(relation) { relation }
+      operation_name :delete_all
+      feature_category :subgroups
+
+      def perform
+        each_sub_batch do |sub_batch|
+          records = sub_batch.joins(
+            "LEFT OUTER JOIN namespaces ON namespaces.id = project_group_links.group_id AND namespaces.type = 'Group'"
+          ).where(namespaces: { id: nil })
+
+          ids = records.map(&:id)
+
+          next if ids.empty?
+
+          Gitlab::AppLogger.info({ message: 'Removing project group link with non-existent groups',
+                                  deleted_count: ids.count,
+                                  ids:  ids })
+
+          records.delete_all
+        end
+      end
+    end
+  end
+end