1 files changed, 41 insertions, 0 deletions
diff --git a/db/post_migrate/20211209103048_backfill_project_namespaces_for_group.rb b/db/post_migrate/20211209103048_backfill_project_namespaces_for_group.rb
new file mode 100644
index 00000000000..44dffc798d3
--- /dev/null
+++ b/db/post_migrate/20211209103048_backfill_project_namespaces_for_group.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+class BackfillProjectNamespacesForGroup < Gitlab::Database::Migration[1.0]
+  MIGRATION = 'ProjectNamespaces::BackfillProjectNamespaces'
+  DELAY_INTERVAL = 2.minutes
+  GROUP_ID = 9970 # picking gitlab-org group.
+
+  disable_ddl_transaction!
+
+  def up
+    return unless Gitlab.com? || Gitlab.staging?
+
+    projects_table = ::Gitlab::BackgroundMigration::ProjectNamespaces::Models::Project.arel_table
+    hierarchy_cte_sql = Arel.sql(::Gitlab::BackgroundMigration::ProjectNamespaces::BackfillProjectNamespaces.hierarchy_cte(GROUP_ID))
+    group_projects = ::Gitlab::BackgroundMigration::ProjectNamespaces::Models::Project.where(projects_table[:namespace_id].in(hierarchy_cte_sql))
+
+    min_id = group_projects.minimum(:id)
+    max_id = group_projects.maximum(:id)
+
+    return if min_id.blank? || max_id.blank?
+
+    queue_batched_background_migration(
+      MIGRATION,
+      :projects,
+      :id,
+      GROUP_ID,
+      'up',
+      job_interval: DELAY_INTERVAL,
+      batch_min_value: min_id,
+      batch_max_value: max_id,
+      sub_batch_size: 25,
+      batch_class_name: 'BackfillProjectNamespacePerGroupBatchingStrategy'
+    )
+  end
+
+  def down
+    return unless Gitlab.com? || Gitlab.staging?
+
+    delete_batched_background_migration(MIGRATION, :projects, :id, [GROUP_ID, 'up'])
+  end
+end