1 files changed, 26 insertions, 0 deletions
diff --git a/lib/gitlab/background_migration/add_merge_request_diff_commits_count.rb b/lib/gitlab/background_migration/add_merge_request_diff_commits_count.rb
new file mode 100644
index 00000000000..7bffffec94d
--- /dev/null
+++ b/lib/gitlab/background_migration/add_merge_request_diff_commits_count.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+# rubocop:disable Style/Documentation
+# rubocop:disable Metrics/LineLength
+
+module Gitlab
+  module BackgroundMigration
+    class AddMergeRequestDiffCommitsCount
+      class MergeRequestDiff < ActiveRecord::Base
+        self.table_name = 'merge_request_diffs'
+      end
+
+      def perform(start_id, stop_id)
+        Rails.logger.info("Setting commits_count for merge request diffs: #{start_id} - #{stop_id}")
+
+        update = '
+          commits_count = (
+            SELECT count(*)
+            FROM merge_request_diff_commits
+            WHERE merge_request_diffs.id = merge_request_diff_commits.merge_request_diff_id
+          )'.squish
+
+        MergeRequestDiff.where(id: start_id..stop_id).update_all(update)
+      end
+    end
+  end
+end