1 files changed, 38 insertions, 0 deletions
diff --git a/lib/gitlab/background_migration/backfill_member_namespace_for_group_members.rb b/lib/gitlab/background_migration/backfill_member_namespace_for_group_members.rb
new file mode 100644
index 00000000000..1ed147d67c7
--- /dev/null
+++ b/lib/gitlab/background_migration/backfill_member_namespace_for_group_members.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module BackgroundMigration
+    # Backfills the `members.member_namespace_id` column for `type=GroupMember`
+    class BackfillMemberNamespaceForGroupMembers
+      include Gitlab::Database::DynamicModelHelpers
+
+      def perform(start_id, end_id, batch_table, batch_column, sub_batch_size, pause_ms)
+        parent_batch_relation = relation_scoped_to_range(batch_table, batch_column, start_id, end_id)
+
+        parent_batch_relation.each_batch(column: batch_column, of: sub_batch_size) do |sub_batch|
+          batch_metrics.time_operation(:update_all) do
+            sub_batch.update_all('member_namespace_id=source_id')
+          end
+
+          pause_ms = [0, pause_ms].max
+          sleep(pause_ms * 0.001)
+        end
+      end
+
+      def batch_metrics
+        @batch_metrics ||= Gitlab::Database::BackgroundMigration::BatchMetrics.new
+      end
+
+      private
+
+      def relation_scoped_to_range(source_table, source_key_column, start_id, stop_id)
+        define_batchable_model(source_table, connection: ActiveRecord::Base.connection)
+          .joins('INNER JOIN namespaces ON members.source_id = namespaces.id')
+          .where(source_key_column => start_id..stop_id)
+          .where(type: 'GroupMember')
+          .where(source_type: 'Namespace')
+          .where(member_namespace_id: nil)
+      end
+    end
+  end
+end