1 files changed, 19 insertions, 33 deletions
diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index 3133dc9e7eb..f1a5cc73e83 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -3,12 +3,11 @@ class MergeRequest < ActiveRecord::Base
   include Issuable
   include Noteable
   include Referable
-  include Sortable
   include IgnorableColumn
-  include CreatedAtFilterable
   include TimeTrackable
 
-  ignore_column :locked_at
+  ignore_column :locked_at,
+                :ref_fetched
 
   belongs_to :target_project, class_name: "Project"
   belongs_to :source_project, class_name: "Project"
@@ -426,7 +425,7 @@ class MergeRequest < ActiveRecord::Base
   end
 
   def create_merge_request_diff
-    fetch_ref
+    fetch_ref!
 
     # n+1: https://gitlab.com/gitlab-org/gitlab-ce/issues/37435
     Gitlab::GitalyClient.allow_n_plus_1_calls do
@@ -577,7 +576,7 @@ class MergeRequest < ActiveRecord::Base
     commit_notes = Note
       .except(:order)
       .where(project_id: [source_project_id, target_project_id])
-      .where(noteable_type: 'Commit', commit_id: commit_ids)
+      .for_commit_id(commit_ids)
 
     # We're using a UNION ALL here since this results in better performance
     # compared to using OR statements. We're using UNION ALL since the queries
@@ -811,29 +810,14 @@ class MergeRequest < ActiveRecord::Base
     end
   end
 
-  def fetch_ref
-    write_ref
-    update_column(:ref_fetched, true)
+  def fetch_ref!
+    target_project.repository.fetch_source_branch!(source_project.repository, source_branch, ref_path)
   end
 
   def ref_path
     "refs/#{Repository::REF_MERGE_REQUEST}/#{iid}/head"
   end
 
-  def ref_fetched?
-    super ||
-      begin
-        computed_value = project.repository.ref_exists?(ref_path)
-        update_column(:ref_fetched, true) if computed_value
-
-        computed_value
-      end
-  end
-
-  def ensure_ref_fetched
-    fetch_ref unless ref_fetched?
-  end
-
   def in_locked_state
     begin
       lock_mr
@@ -881,7 +865,19 @@ class MergeRequest < ActiveRecord::Base
   #
   def all_commit_shas
     if persisted?
-      column_shas = MergeRequestDiffCommit.where(merge_request_diff: merge_request_diffs).limit(10_000).pluck('sha')
+      # MySQL doesn't support LIMIT in a subquery.
+      diffs_relation =
+        if Gitlab::Database.postgresql?
+          merge_request_diffs.order(id: :desc).limit(100)
+        else
+          merge_request_diffs
+        end
+
+      column_shas = MergeRequestDiffCommit
+                      .where(merge_request_diff: diffs_relation)
+                      .limit(10_000)
+                      .pluck('sha')
+
       serialised_shas = merge_request_diffs.where.not(st_commits: nil).flat_map(&:commit_shas)
 
       (column_shas + serialised_shas).uniq
@@ -962,10 +958,6 @@ class MergeRequest < ActiveRecord::Base
     true
   end
 
-  def update_project_counter_caches?
-    state_changed?
-  end
-
   def update_project_counter_caches
     Projects::OpenMergeRequestsCountService.new(target_project).refresh_cache
   end
@@ -975,10 +967,4 @@ class MergeRequest < ActiveRecord::Base
 
     project.merge_requests.merged.where(author_id: author_id).empty?
   end
-
-  private
-
-  def write_ref
-    target_project.repository.fetch_source_branch(source_project.repository, source_branch, ref_path)
-  end
 end