Eliminate N+1 queries in LFS file locks checks during a push

This significantly improves performance when a user pushes many references.

project.path_locks.any? doesn't cache the output and runs `SELECT 1 AS one
FROM "path_locks" WHERE project_id = N` each time. When there are thousands
of refs being pushed, this can time out the unicorn worker.

CE port for https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/6159.

1 files changed, 6 insertions, 0 deletions

diff --git a/app/models/project.rb b/app/models/project.rb
index e5fa1c4db7b..0d777515536 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -25,6 +25,7 @@ class Project < ActiveRecord::Base
   include FastDestroyAll::Helpers
   include WithUploads
   include BatchDestroyDependentAssociations
+  extend Gitlab::Cache::RequestCache
 
   extend Gitlab::ConfigHelper
 
@@ -2013,6 +2014,11 @@ class Project < ActiveRecord::Base
     @gitlab_deploy_token ||= deploy_tokens.gitlab_deploy_token
   end
 
+  def any_lfs_file_locks?
+    lfs_file_locks.any?
+  end
+  request_cache(:any_lfs_file_locks?) { self.id }
+
   private
 
   def storage