Remove Redundant Persistent Ref existence check

This commit addresses mitigates the performance concern.

app/presenters/ci/build_runner_presenter.rb

@@ -97,6 +97,13 @@ module Ci
     end
 
     def persistent_ref_exist?
+      ##
+      # Persistent refs for pipelines definitely exist from GitLab 12.4,
+      # hence, we don't need to check the ref existence before passing it to runners.
+      # Checking refs pressurizes gitaly node and should be avoided.
+      # Issue: https://gitlab.com/gitlab-com/gl-infra/production/-/issues/2143
+      return true if Feature.enabled?(:ci_skip_persistent_ref_existence_check)
+
       pipeline.persistent_ref.exist?
     end
 

spec/presenters/ci/build_runner_presenter_spec.rb

@@ -185,16 +185,19 @@ describe Ci::BuildRunnerPresenter do
     subject { presenter.refspecs }
 
     let(:build) { create(:ci_build) }
+    let(:pipeline) { build.pipeline }
 
     it 'returns the correct refspecs' do
-      is_expected.to contain_exactly("+refs/heads/#{build.ref}:refs/remotes/origin/#{build.ref}")
+      is_expected.to contain_exactly("+refs/heads/#{build.ref}:refs/remotes/origin/#{build.ref}",
+                                     "+refs/pipelines/#{pipeline.id}:refs/pipelines/#{pipeline.id}")
     end
 
     context 'when ref is tag' do
       let(:build) { create(:ci_build, :tag) }
 
       it 'returns the correct refspecs' do
-        is_expected.to contain_exactly("+refs/tags/#{build.ref}:refs/tags/#{build.ref}")
+        is_expected.to contain_exactly("+refs/tags/#{build.ref}:refs/tags/#{build.ref}",
+                                       "+refs/pipelines/#{pipeline.id}:refs/pipelines/#{pipeline.id}")
       end
 
       context 'when GIT_DEPTH is zero' do
@@ -204,7 +207,8 @@ describe Ci::BuildRunnerPresenter do
 
         it 'returns the correct refspecs' do
           is_expected.to contain_exactly('+refs/tags/*:refs/tags/*',
-                                         '+refs/heads/*:refs/remotes/origin/*')
+                                         '+refs/heads/*:refs/remotes/origin/*',
+                                         "+refs/pipelines/#{pipeline.id}:refs/pipelines/#{pipeline.id}")
         end
       end
     end

spec/requests/api/runner_spec.rb

@@ -471,7 +471,8 @@ describe API::Runner, :clean_gitlab_redis_shared_state do
               'sha' => job.sha,
               'before_sha' => job.before_sha,
               'ref_type' => 'branch',
-              'refspecs' => ["+refs/heads/#{job.ref}:refs/remotes/origin/#{job.ref}"],
+              'refspecs' => ["+refs/pipelines/#{pipeline.id}:refs/pipelines/#{pipeline.id}",
+                             "+refs/heads/#{job.ref}:refs/remotes/origin/#{job.ref}"],
               'depth' => project.ci_default_git_depth }
           end
 
@@ -578,7 +579,9 @@ describe API::Runner, :clean_gitlab_redis_shared_state do
 
                 expect(response).to have_gitlab_http_status(:created)
                 expect(json_response['git_info']['refspecs'])
-                  .to contain_exactly('+refs/tags/*:refs/tags/*', '+refs/heads/*:refs/remotes/origin/*')
+                  .to contain_exactly("+refs/pipelines/#{pipeline.id}:refs/pipelines/#{pipeline.id}",
+                                      '+refs/tags/*:refs/tags/*',
+                                      '+refs/heads/*:refs/remotes/origin/*')
               end
             end
           end
@@ -638,7 +641,9 @@ describe API::Runner, :clean_gitlab_redis_shared_state do
 
                 expect(response).to have_gitlab_http_status(:created)
                 expect(json_response['git_info']['refspecs'])
-                  .to contain_exactly('+refs/tags/*:refs/tags/*', '+refs/heads/*:refs/remotes/origin/*')
+                  .to contain_exactly("+refs/pipelines/#{pipeline.id}:refs/pipelines/#{pipeline.id}",
+                                      '+refs/tags/*:refs/tags/*',
+                                      '+refs/heads/*:refs/remotes/origin/*')
               end
             end
           end