diff --git a/app/services/merge_requests/refresh_service.rb b/app/services/merge_requests/refresh_service.rb
index c47714fbd4bb8cfed4e8a038db74f61b922aba9b..1486dd31ebef42317a67964383807a1e36a09860 100644
--- a/app/services/merge_requests/refresh_service.rb
+++ b/app/services/merge_requests/refresh_service.rb
@@ -91,16 +91,20 @@ def close_upon_missing_source_branch_ref
     # rubocop: disable CodeReuse/ActiveRecord
     def post_merge_manually_merged
       commit_ids = @commits.map(&:id)
-      merge_requests = @project.merge_requests.opened
-        .preload_project_and_latest_diff
-        .preload_latest_diff_commit
-        .where(target_branch: @push.branch_name).to_a
-        .select(&:diff_head_commit)
-        .select do |merge_request|
-          commit_ids.include?(merge_request.diff_head_sha) &&
-            merge_request.merge_request_diff.state != 'empty'
-        end
-      merge_requests = filter_merge_requests(merge_requests)
+      merge_requests = []
+
+      @project.merge_requests.opened.each_batch(of: 500) do |mrs|
+        merge_requests << mrs.preload_project_and_latest_diff
+          .preload_latest_diff_commit
+          .where(target_branch: @push.branch_name).to_a
+          .select(&:diff_head_commit)
+          .select do |merge_request|
+            commit_ids.include?(merge_request.diff_head_sha) &&
+              merge_request.merge_request_diff.state != 'empty'
+          end
+      end
+
+      merge_requests = filter_merge_requests(merge_requests.flatten)
 
       return if merge_requests.empty?