Avoid open/close transaction in each gon helper callproper-default-issue-tracker

require 'benchmark/ips'

Project.first # To load database things
GitlabIssueTrackerService.first # To load database things

Benchmark.ips do |x|
  x.config(:time => 5, :warmup => 2)

  x.report("current") do
    Project.new.default_issue_tracker.to_param
  end

  x.report("") do
    Project.default_issue_tracker_service_name
  end

  x.compare!
end


Calculating -------------------------------------
             current     3.000  i/100ms
                        22.466k i/100ms
-------------------------------------------------
             current     39.875  (±15.0%) i/s -    192.000 
                          1.444M (±14.8%) i/s -      6.605M

Comparison:
                    :  1443612.8 i/s
             current:       39.9 i/s - 36203.16x slower

6 files changed, 23 insertions, 6 deletions

diff --git a/app/models/project.rb b/app/models/project.rb
index ca3bc04e2dd..d9d572e81c3 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -372,6 +372,14 @@ class Project < ActiveRecord::Base
     def remove_gitlab_exports!
       Gitlab::Popen.popen(%W(find #{Gitlab::ImportExport.storage_path} -not -path #{Gitlab::ImportExport.storage_path} -mmin +1440 -delete))
     end
+
+    def default_issue_tracker_service
+      :gitlab_issue_tracker_service
+    end
+
+    def default_issue_tracker_service_name
+      reflect_on_association(default_issue_tracker_service).klass::NAME
+    end
   end
 
   def team
@@ -583,8 +591,12 @@ class Project < ActiveRecord::Base
     get_issue(issue_id)
   end
 
+  def default_issue_tracker_service
+    self.class.default_issue_tracker_service
+  end
+
   def default_issue_tracker
-    gitlab_issue_tracker_service || create_gitlab_issue_tracker_service
+    association(default_issue_tracker_service).target || association(default_issue_tracker_service).create
   end
 
   def issues_tracker
diff --git a/app/models/project_services/custom_issue_tracker_service.rb b/app/models/project_services/custom_issue_tracker_service.rb
index 6b2b1daa724..6a95f6eeaf9 100644
--- a/app/models/project_services/custom_issue_tracker_service.rb
+++ b/app/models/project_services/custom_issue_tracker_service.rb
@@ -1,4 +1,5 @@
 class CustomIssueTrackerService < IssueTrackerService
+  NAME = 'custom_issue_tracker'
 
   prop_accessor :title, :description, :project_url, :issues_url, :new_issue_url
 
@@ -19,7 +20,7 @@ class CustomIssueTrackerService < IssueTrackerService
   end
 
   def to_param
-    'custom_issue_tracker'
+    NAME
   end
 
   def fields
diff --git a/app/models/project_services/gitlab_issue_tracker_service.rb b/app/models/project_services/gitlab_issue_tracker_service.rb
index 5d17c358330..ef17ec4e393 100644
--- a/app/models/project_services/gitlab_issue_tracker_service.rb
+++ b/app/models/project_services/gitlab_issue_tracker_service.rb
@@ -1,12 +1,14 @@
 class GitlabIssueTrackerService < IssueTrackerService
   include Gitlab::Routing.url_helpers
 
+  NAME = 'gitlab'
+
   prop_accessor :title, :description, :project_url, :issues_url, :new_issue_url
 
   default_value_for :default, true
 
   def to_param
-    'gitlab'
+    NAME
   end
 
   def project_url
diff --git a/app/models/project_services/jira_service.rb b/app/models/project_services/jira_service.rb
index beda89d3963..80c20291288 100644
--- a/app/models/project_services/jira_service.rb
+++ b/app/models/project_services/jira_service.rb
@@ -3,6 +3,7 @@ class JiraService < IssueTrackerService
   include Gitlab::Routing.url_helpers
 
   DEFAULT_API_VERSION = 2
+  NAME = 'jira'
 
   prop_accessor :username, :password, :api_url, :jira_issue_transition_id,
                 :title, :description, :project_url, :issues_url, :new_issue_url
@@ -44,7 +45,7 @@ class JiraService < IssueTrackerService
   end
 
   def to_param
-    'jira'
+    NAME
   end
 
   def fields
diff --git a/app/models/project_services/redmine_service.rb b/app/models/project_services/redmine_service.rb
index 11cce3e0561..03f8440c224 100644
--- a/app/models/project_services/redmine_service.rb
+++ b/app/models/project_services/redmine_service.rb
@@ -1,4 +1,5 @@
 class RedmineService < IssueTrackerService
+  NAME = 'redmine'
 
   prop_accessor :title, :description, :project_url, :issues_url, :new_issue_url
 
@@ -19,6 +20,6 @@ class RedmineService < IssueTrackerService
   end
 
   def to_param
-    'redmine'
+    NAME
   end
 end
diff --git a/lib/gitlab/gon_helper.rb b/lib/gitlab/gon_helper.rb
index f751a3a12fd..689c5237588 100644
--- a/lib/gitlab/gon_helper.rb
+++ b/lib/gitlab/gon_helper.rb
@@ -3,7 +3,7 @@ module Gitlab
     def add_gon_variables
       gon.api_version            = API::API.version
       gon.default_avatar_url     = URI::join(Gitlab.config.gitlab.url, ActionController::Base.helpers.image_path('no_avatar.png')).to_s
-      gon.default_issues_tracker = Project.new.default_issue_tracker.to_param
+      gon.default_issues_tracker = Project.default_issue_tracker_service_name
       gon.max_file_size          = current_application_settings.max_attachment_size
       gon.relative_url_root      = Gitlab.config.gitlab.relative_url_root
       gon.shortcuts_path         = help_shortcuts_path