Improve performance of the cycle analytics page.

1. These changes bring down page load time for 100 issues from more than
   a minute to about 1.5 seconds.

2. This entire commit is composed of these types of performance
   enhancements:

     - Cache relevant data in `IssueMetrics` wherever possible.
     - Cache relevant data in `MergeRequestMetrics` wherever possible.
     - Preload metrics

3. Given these improvements, we now only need to make 4 SQL calls:

    - Load all issues
    - Load all merge requests
    - Load all metrics for the issues
    - Load all metrics for the merge requests

4. A list of all the data points that are now being pre-calculated:

    a. The first time an issue is mentioned in a commit

      - In `GitPushService`, find all issues mentioned by the given commit
        using `ReferenceExtractor`. Set the `first_mentioned_in_commit_at`
        flag for each of them.

      - There seems to be a (pre-existing) bug here - files (and
        therefore commits) created using the Web CI don't have
        cross-references created, and issues are not closed even when
        the commit title is "Fixes #xx".

    b. The first time a merge request is deployed to production

      When a `Deployment` is created, find all merge requests that
      were merged in before the deployment, and set the
      `first_deployed_to_production_at` flag for each of them.

    c. The start / end time for a merge request pipeline

      Hook into the `Pipeline` state machine. When the `status` moves to
      `running`, find the merge requests whose tip commit matches the
      pipeline, and record the `latest_build_started_at` time for each
      of them. When the `status` moves to `success`, record the
      `latest_build_finished_at` time.

    d. The merge requests that close an issue

      - This was a big cause of the performance problems we were having
        with Cycle Analytics. We need to use `ReferenceExtractor` to make
        this calculation, which is slow when we have to run it on a large
        number of merge requests.

      - When a merge request is created, updated, or refreshed, find the
        issues it closes, and create an instance of
        `MergeRequestsClosingIssues`, which acts as a join model between
        merge requests and issues.

      - If a `MergeRequestsClosingIssues` instance links a merge request
        and an issue, that issue closes that merge request.

5. The `Queries` module was changed into a class, so we can cache the
   results of `issues` and `merge_requests_closing_issues` across
   various cycle analytics stages.

6. The code added in this commit is untested. Tests will be added in the
   next commit.

app/models/ci/pipeline.rb

@@ -55,6 +55,18 @@ module Ci
         pipeline.finished_at = Time.now
       end
+      after_transition [:created, :pending] => :running do |pipeline|
+        pipeline.merge_requests.each do |merge_request|
+          merge_request.metrics.record_latest_build_start_time!(pipeline.started_at) if merge_request.metrics.present?
+        end
+      end
+
+      after_transition any => [:success] do |pipeline|
+        pipeline.merge_requests.each do |merge_request|
+          merge_request.metrics.record_latest_build_finish_time!(pipeline.finished_at) if merge_request.metrics.present?
+        end
+      end
+
       before_transition do |pipeline|
         pipeline.update_duration
       end
@@ -267,6 +279,13 @@ module Ci
       project.execute_services(data, :pipeline_hooks)
     end
+    # Merge requests for which the current pipeline is running against
+    # the merge request's latest commit.
+    def merge_requests
+      project.merge_requests.where(source_branch: self.ref).
+        select { |merge_request| merge_request.pipeline.id == self.id }
+    end
+
     private
     def pipeline_data

app/models/cycle_analytics.rb

@@ -2,8 +2,8 @@ class CycleAnalytics
   attr_reader :from
   def initialize(project, from:)
-    @project = project
     @from = from
+    @queries = Queries.new(project)
   end
   def as_json(options = {})
@@ -14,45 +14,45 @@ class CycleAnalytics
   end
   def issue
-    calculate_metric(Queries::issues(@project, created_after: @from),
+    calculate_metric(@queries.issues(created_after: @from),
                      -> (data_point) { data_point[:issue].created_at },
-                     [Queries::issue_first_associated_with_milestone_at, Queries::issue_first_added_to_list_label_at])
+                     [@queries.issue_first_associated_with_milestone_at, @queries.issue_first_added_to_list_label_at])
   end
   def plan
-    calculate_metric(Queries::issues(@project, created_after: @from),
-                     [Queries::issue_first_associated_with_milestone_at, Queries::issue_first_added_to_list_label_at],
-                     Queries::issue_first_mentioned_in_commit_at)
+    calculate_metric(@queries.issues(created_after: @from),
+                     [@queries.issue_first_associated_with_milestone_at, @queries.issue_first_added_to_list_label_at],
+                     @queries.issue_first_mentioned_in_commit_at)
   end
   def code
-    calculate_metric(Queries::merge_requests_closing_issues(@project, created_after: @from),
-                     Queries::issue_first_mentioned_in_commit_at,
+    calculate_metric(@queries.merge_requests_closing_issues(created_after: @from),
+                     @queries.issue_first_mentioned_in_commit_at,
                      -> (data_point) { data_point[:merge_request].created_at })
   end
   def test
-    calculate_metric(Queries::merge_requests_closing_issues(@project, created_after: @from),
-                     Queries::merge_request_build_started_at,
-                     Queries::merge_request_build_finished_at)
+    calculate_metric(@queries.merge_requests_closing_issues(created_after: @from),
+                     @queries.merge_request_build_started_at,
+                     @queries.merge_request_build_finished_at)
   end
   def review
-    calculate_metric(Queries::merge_requests_closing_issues(@project, created_after: @from),
+    calculate_metric(@queries.merge_requests_closing_issues(created_after: @from),
                      -> (data_point) { data_point[:merge_request].created_at },
-                     Queries::merge_request_merged_at)
+                     @queries.merge_request_merged_at)
   end
   def staging
-    calculate_metric(Queries::merge_requests_closing_issues(@project, created_after: @from),
-                     Queries::merge_request_merged_at,
-                     Queries::merge_request_deployed_to_production_at)
+    calculate_metric(@queries.merge_requests_closing_issues(created_after: @from),
+                     @queries.merge_request_merged_at,
+                     @queries.merge_request_deployed_to_production_at)
   end
   def production
-    calculate_metric(Queries::merge_requests_closing_issues(@project, created_after: @from),
+    calculate_metric(@queries.merge_requests_closing_issues(created_after: @from),
                      -> (data_point) { data_point[:issue].created_at },
-                     Queries::merge_request_deployed_to_production_at)
+                     @queries.merge_request_deployed_to_production_at)
   end
   private

app/models/cycle_analytics/queries.rb

 class CycleAnalytics
-  module Queries
-    class << self
-      def issues(project, created_after:)
-        project.issues.where("created_at >= ?", created_after).preload(:metrics, :system_notes).map { |issue| { issue: issue } }
-      end
-
-      def merge_requests_closing_issues(project, options = {})
-        issues(project, options).map do |data_point|
-          merge_requests = data_point[:issue].closed_by_merge_requests(nil, check_if_open: false)
-          merge_requests.map { |merge_request| { issue: data_point[:issue], merge_request: merge_request } }
-        end.flatten
-      end
-      def issue_first_associated_with_milestone_at
-        lambda do |data_point|
-          issue = data_point[:issue]
-          issue.metrics.first_associated_with_milestone_at if issue.metrics.present?
+  class Queries
+    def initialize(project)
+      @project = project
+    end
+    def issues(options = {})
+      @issues_data ||=
+        begin
+          issues_query(options).preload(:metrics).map { |issue| { issue: issue } }
         end
-      end
-      def issue_first_added_to_list_label_at
-        lambda do |data_point|
-          issue = data_point[:issue]
-          issue.metrics.first_added_to_board_at if issue.metrics.present?
-        end
-      end
-      def issue_first_mentioned_in_commit_at
-        lambda do |data_point|
-          issue = data_point[:issue]
-          commits_mentioning_issue = issue.system_notes.map { |note| note.all_references.commits }.flatten
-          commits_mentioning_issue.map(&:committed_date).min if commits_mentioning_issue.present?
+    end
+    def merge_requests_closing_issues(options = {})
+      @merge_requests_closing_issues_data ||=
+        begin
+          merge_requests_closing_issues = MergeRequestsClosingIssues.where(issue: issues_query(options)).preload(issue: [:metrics], merge_request: [:metrics])
+          merge_requests_closing_issues.map do |record|
+            { issue: record.issue, merge_request: record.merge_request }
+          end
         end
-      end
-      def merge_request_first_closed_at
-        lambda do |data_point|
-          merge_request = data_point[:merge_request]
-          merge_request.metrics.first_closed_at if merge_request.metrics.present?
-        end
+    end
+    def issue_first_associated_with_milestone_at
+      lambda do |data_point|
+        issue = data_point[:issue]
+        issue.metrics.first_associated_with_milestone_at if issue.metrics.present?
       end
-      def merge_request_merged_at
-        lambda do |data_point|
-          merge_request = data_point[:merge_request]
-          merge_request.metrics.merged_at if merge_request.metrics.present?
-        end
+    end
+    def issue_first_added_to_list_label_at
+      lambda do |data_point|
+        issue = data_point[:issue]
+        issue.metrics.first_added_to_board_at if issue.metrics.present?
       end
-      def merge_request_build_started_at
-        lambda do |data_point|
-          merge_request = data_point[:merge_request]
-          tip = merge_request.commits.first
-          return unless tip
-
-          pipeline = Ci::Pipeline.success.find_by_sha(tip.sha)
-          pipeline.started_at if pipeline
-        end
+    end
+    def issue_first_mentioned_in_commit_at
+      lambda do |data_point|
+        issue = data_point[:issue]
+        issue.metrics.first_mentioned_in_commit_at if issue.metrics.present?
       end
-      def merge_request_build_finished_at
-        lambda do |data_point|
-          merge_request = data_point[:merge_request]
-          tip = merge_request.commits.first
-          return unless tip
-
-          pipeline = Ci::Pipeline.success.find_by_sha(tip.sha)
-          pipeline.finished_at if pipeline
-        end
+    end
+    def merge_request_merged_at
+      lambda do |data_point|
+        merge_request = data_point[:merge_request]
+        merge_request.metrics.merged_at if merge_request.metrics.present?
       end
-      def merge_request_deployed_to_any_environment_at
-        lambda do |data_point|
-          merge_request = data_point[:merge_request]
-          if merge_request.metrics.present?
-            deployments = Deployment.where(ref: merge_request.target_branch).where("created_at > ?", merge_request.metrics.merged_at)
-            deployment = deployments.order(:created_at).first
-            deployment.created_at if deployment
-          end
-        end
+    end
+    def merge_request_build_started_at
+      lambda do |data_point|
+        merge_request = data_point[:merge_request]
+        merge_request.metrics.latest_build_started_at if merge_request.metrics.present?
       end
-      def merge_request_deployed_to_production_at
-        lambda do |data_point|
-          merge_request = data_point[:merge_request]
-          if merge_request.metrics.present?
-            # The first production deploy to the target branch that occurs after the merge request has been merged in.
-            # TODO: Does this need to account for reverts?
-            deployments = Deployment.joins(:environment).where(ref: merge_request.target_branch, "environments.name" => "production").
-                          where("deployments.created_at > ?", merge_request.metrics.merged_at)
-            deployment = deployments.order(:created_at).first
-            deployment.created_at if deployment
-          end
-        end
+    end
+    def merge_request_build_finished_at
+      lambda do |data_point|
+        merge_request = data_point[:merge_request]
+        merge_request.metrics.latest_build_finished_at if merge_request.metrics.present?
       end
-      def issue_closing_merge_request_opened_at
-        lambda do |data_point|
-          issue = data_point[:issue]
-          merge_requests = issue.closed_by_merge_requests(nil, check_if_open: false)
-          merge_requests.map(&:created_at).min if merge_requests.present?
-        end
+    end
+    def merge_request_deployed_to_production_at
+      lambda do |data_point|
+        merge_request = data_point[:merge_request]
+        merge_request.metrics.first_deployed_to_production_at if merge_request.metrics.present?
       end
-      def merge_request_wip_flag_first_removed_at
-        lambda do |data_point|
-          merge_request = data_point[:merge_request]
-          merge_request.metrics.wip_flag_first_removed_at if merge_request.metrics.present?
-        end
-      end
-      def merge_request_first_assigned_to_user_other_than_author_at
-        lambda do |data_point|
-          merge_request = data_point[:merge_request]
-          merge_request.metrics.first_assigned_to_user_other_than_author if merge_request.metrics.present?
-        end
-      end
+    end
+    private
+    def issues_query(created_after:)
+      @project.issues.where("created_at >= ?", created_after)
     end
   end
 end

app/models/issue.rb

@@ -25,6 +25,9 @@ class Issue < ActiveRecord::Base
   has_one :metrics, dependent: :destroy
+  has_many :merge_requests_closing_issues, class_name: MergeRequestsClosingIssues
+  has_many :closed_by_merge_requests, through: :merge_requests_closing_issues, source: :merge_request
+
   validates :project, presence: true
   scope :cared, ->(user) { where(assignee_id: user) }

app/models/issue/metrics.rb

@@ -13,6 +13,10 @@ class Issue::Metrics < ActiveRecord::Base
     self.save if self.changed?
   end
+  def record_commit_mention!(commit_time)
+    self.update(first_mentioned_in_commit_at: commit_time) if self.first_mentioned_in_commit_at.blank?
+  end
+
   private
   def issue_assigned_to_list_label?

app/models/merge_request.rb

@@ -17,6 +17,9 @@ class MergeRequest < ActiveRecord::Base
   has_many :events, as: :target, dependent: :destroy
+  has_many :merge_requests_closing_issues, class_name: MergeRequestsClosingIssues
+  has_many :issues_closed, through: :merge_requests_closing_issues, source: :issue
+
   serialize :merge_params, Hash
   after_create :ensure_merge_request_diff, unless: :importing?
@@ -494,6 +497,18 @@ class MergeRequest < ActiveRecord::Base
     target_project
   end
+  # If the merge request closes any issues, save this information in the
+  # `MergeRequestsClosingIssues` model. This is a performance optimization.
+  # Calculating this information for a number of merge requests requires
+  # running `ReferenceExtractor` on each of them separately.
+  def cache_merge_request_closes_issues!(current_user = self.author)
+    transaction do
+      closes_issues(current_user).each do |issue|
+        MergeRequestsClosingIssues.create!(merge_request: self, issue: issue)
+      end
+    end
+  end
+
   def closes_issue?(issue)
     closes_issues.include?(issue)
   end

app/models/merge_request/metrics.rb

@@ -20,4 +20,16 @@ class MergeRequest::Metrics < ActiveRecord::Base
     self.save if self.changed?
   end
+
+  def record_production_deploy!(deploy_time)
+    self.update(first_deployed_to_production_at: deploy_time) if self.first_deployed_to_production_at.blank?
+  end
+
+  def record_latest_build_start_time!(start_time)
+    self.update(latest_build_started_at: start_time, latest_build_finished_at: nil)
+  end
+
+  def record_latest_build_finish_time!(finish_time)
+    self.update(latest_build_finished_at: finish_time)
+  end
 end

app/models/merge_requests_closing_issues.rb

+class MergeRequestsClosingIssues < ActiveRecord::Base
+  belongs_to :merge_request
+  belongs_to :issue
+end

app/services/create_deployment_service.rb

@@ -6,7 +6,7 @@ class CreateDeploymentService < BaseService
       name: params[:environment]
     )
-    project.deployments.create(
+    deployment = project.deployments.create(
       environment: environment,
       ref: params[:ref],
       tag: params[:tag],
@@ -14,5 +14,26 @@ class CreateDeploymentService < BaseService
       user: current_user,
       deployable: deployable
     )
+
+    update_merge_request_metrics(deployment, environment)
+
+    deployment
+  end
+
+  private
+
+  def update_merge_request_metrics(deployment, environment)
+    # TODO: Test cases:
+    # 1. Merge request with metrics available and `first_deployed_to_production_at` is nil
+    # 2. Merge request with metrics available and `first_deployed_to_production_at` is set
+    # 3. Merge request with metrics unavailable
+    # 4. Only applies to merge requests merged AFTER the previous production deploy to this branch
+    if environment.name == "production"
+      merge_requests_deployed_to_production_for_first_time = project.merge_requests.joins("LEFT OUTER JOIN merge_request_metrics ON merge_request_metrics.merge_request_id = merge_requests.id").
+                                                             where(target_branch: params[:ref], "merge_request_metrics.first_deployed_to_production_at" => nil).
+                                                             where("merge_request_metrics.merged_at < ?", deployment.created_at)
+
+      merge_requests_deployed_to_production_for_first_time.each { |merge_request| merge_request.metrics.record_production_deploy!(deployment.created_at) }
+    end
   end
 end

app/services/git_push_service.rb

@@ -134,6 +134,7 @@ class GitPushService < BaseService
       end
       commit.create_cross_references!(authors[commit], closed_issues)
+      update_issue_metrics(commit, authors)
     end
   end
@@ -186,4 +187,10 @@ class GitPushService < BaseService
   def branch_name
     @branch_name ||= Gitlab::Git.ref_name(params[:ref])
   end
+
+  # TODO: What about commits created using the Web UI? Cross references are not created there.
+  def update_issue_metrics(commit, authors)
+    mentioned_issues = commit.all_references(authors[commit]).issues
+    mentioned_issues.each { |issue| issue.metrics.record_commit_mention!(commit.committed_date) if issue.metrics.present? }
+  end
 end

app/services/merge_requests/base_service.rb

@@ -35,6 +35,18 @@ module MergeRequests
       end
     end
+    def create(merge_request)
+      merge_request = super(merge_request)
+      merge_request.cache_merge_request_closes_issues!(current_user)
+      merge_request
+    end
+
+    def update(merge_request)
+      merge_request = super(merge_request)
+      merge_request.cache_merge_request_closes_issues!(current_user)
+      merge_request
+    end
+
     private
     def filter_params

app/services/merge_requests/refresh_service.rb

@@ -13,6 +13,7 @@ module MergeRequests
       reload_merge_requests
       reset_merge_when_build_succeeds
       mark_pending_todos_done
+      cache_merge_requests_closing_issues
       # Leave a system note if a branch was deleted/added
       if branch_added? || branch_removed?
@@ -141,6 +142,14 @@ module MergeRequests
       end
     end
+    # If the merge requests closes any issues, save this information in the
+    # `MergeRequestsClosingIssues` model (as a performance optimization).
+    def cache_merge_requests_closing_issues
+      merge_requests_for_source_branch.each do |merge_request|
+        merge_request.cache_merge_request_closes_issues!(@current_user)
+      end
+    end
+
     def filter_merge_requests(merge_requests)
       merge_requests.uniq.select(&:source_project)
     end

db/fixtures/development/17_cycle_analytics.rb

@@ -24,30 +24,37 @@ class Gitlab::Seeder::CycleAnalytics
   def seed!
     Sidekiq::Testing.inline! do
       issues = create_issues(@project)
+      print '.'
       # Stage 1
       Timecop.travel 5.days.from_now
       add_milestones_and_list_labels(issues)
+      print '.'
       # Stage 2
       Timecop.travel 5.days.from_now
       branches = mention_in_commits(issues)
+      print '.'
       # Stage 3
       Timecop.travel 5.days.from_now
       merge_requests = create_merge_requests_closing_issues(issues, branches)
+      print '.'
       # Stage 4
       Timecop.travel 5.days.from_now
       run_builds(merge_requests)
+      print '.'
       # Stage 5
       Timecop.travel 5.days.from_now
       merge_merge_requests(merge_requests)
+      print '.'
       # Stage 6 / 7
       Timecop.travel 5.days.from_now
       deploy_to_production(merge_requests)
+      print '.'
     end
     print '.'
@@ -101,8 +108,14 @@ class Gitlab::Seeder::CycleAnalytics
       }
       commit_sha = Gitlab::Git::Blob.commit(issue.project.repository, options)
-      commit = issue.project.repository.commit(commit_sha)
-      commit.create_cross_references!
+      issue.project.repository.commit(commit_sha)
+
+
+      GitPushService.new(issue.project,
+                         @user,
+                         oldrev: issue.project.repository.commit("master").sha,
+                         newrev: commit_sha,
+                         ref: 'refs/heads/master').execute
       branch_name
     end
@@ -162,10 +175,12 @@ end
 Gitlab::Seeder.quiet do
   if ENV['SEED_CYCLE_ANALYTICS']
-      seeder = Gitlab::Seeder::CycleAnalytics.new(Project.find(1))
+    Project.all.each do |project|
+      seeder = Gitlab::Seeder::CycleAnalytics.new(project)
       seeder.seed!
+    end
   elsif ENV['CYCLE_ANALYTICS_PERF_TEST']
-    seeder = Gitlab::Seeder::CycleAnalytics.new(Project.first, perf: true)
+    seeder = Gitlab::Seeder::CycleAnalytics.new(Project.order(:id).first, perf: true)
     seeder.seed!
   else
     puts "Not running the cycle analytics seed file. Use the `SEED_CYCLE_ANALYTICS` environment variable to enable it."

db/migrate/20160915042921_create_merge_requests_closing_issues.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class CreateMergeRequestsClosingIssues < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  # Set this constant to true if this migration requires downtime.
+  DOWNTIME = true
+
+  # When a migration requires downtime you **must** uncomment the following
+  # constant and define a short and easy to understand explanation as to why the
+  # migration requires downtime.
+  DOWNTIME_REASON = 'Adding foreign keys'
+
+  # When using the methods "add_concurrent_index" or "add_column_with_default"
+  # you must disable the use of transactions as these methods can not run in an
+  # existing transaction. When using "add_concurrent_index" make sure that this
+  # method is the _only_ method called in the migration, any other changes
+  # should go in a separate migration. This ensures that upon failure _only_ the
+  # index creation fails and can be retried or reverted easily.
+  #
+  # To disable transactions uncomment the following line and remove these
+  # comments:
+  # disable_ddl_transaction!
+
+  def change
+    create_table :merge_requests_closing_issues do |t|
+      t.references :merge_request, foreign_key: true, null: false
+      t.references :issue, foreign_key: true, null: false
+
+      t.timestamps null: false
+    end
+  end
+end

db/migrate/20160915061248_add_production_deploy_time_to_merge_request_metrics.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class AddProductionDeployTimeToMergeRequestMetrics < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  # Set this constant to true if this migration requires downtime.
+  DOWNTIME = false
+
+  # When a migration requires downtime you **must** uncomment the following
+  # constant and define a short and easy to understand explanation as to why the
+  # migration requires downtime.
+  # DOWNTIME_REASON = ''
+
+  # When using the methods "add_concurrent_index" or "add_column_with_default"
+  # you must disable the use of transactions as these methods can not run in an
+  # existing transaction. When using "add_concurrent_index" make sure that this
+  # method is the _only_ method called in the migration, any other changes
+  # should go in a separate migration. This ensures that upon failure _only_ the
+  # index creation fails and can be retried or reverted easily.
+  #
+  # To disable transactions uncomment the following line and remove these
+  # comments:
+  # disable_ddl_transaction!
+
+  def change
+    add_column :merge_request_metrics, :first_deployed_to_production_at, :datetime
+  end
+end

db/migrate/20160915072217_add_first_mentioned_in_commit_time_to_issue_metrics.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class AddFirstMentionedInCommitTimeToIssueMetrics < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  # Set this constant to true if this migration requires downtime.
+  DOWNTIME = false
+
+  # When a migration requires downtime you **must** uncomment the following
+  # constant and define a short and easy to understand explanation as to why the
+  # migration requires downtime.
+  # DOWNTIME_REASON = ''
+
+  # When using the methods "add_concurrent_index" or "add_column_with_default"
+  # you must disable the use of transactions as these methods can not run in an
+  # existing transaction. When using "add_concurrent_index" make sure that this
+  # method is the _only_ method called in the migration, any other changes
+  # should go in a separate migration. This ensures that upon failure _only_ the
+  # index creation fails and can be retried or reverted easily.
+  #
+  # To disable transactions uncomment the following line and remove these
+  # comments:
+  # disable_ddl_transaction!
+
+  def change
+    add_column :issue_metrics, :first_mentioned_in_commit_at, :datetime
+  end
+end

db/migrate/20160915081353_add_latest_build_time_to_merge_request_metrics.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class AddLatestBuildTimeToMergeRequestMetrics < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  # Set this constant to true if this migration requires downtime.
+  DOWNTIME = false
+
+  # When a migration requires downtime you **must** uncomment the following
+  # constant and define a short and easy to understand explanation as to why the
+  # migration requires downtime.
+  # DOWNTIME_REASON = ''
+
+  # When using the methods "add_concurrent_index" or "add_column_with_default"
+  # you must disable the use of transactions as these methods can not run in an
+  # existing transaction. When using "add_concurrent_index" make sure that this
+  # method is the _only_ method called in the migration, any other changes
+  # should go in a separate migration. This ensures that upon failure _only_ the
+  # index creation fails and can be retried or reverted easily.
+  #
+  # To disable transactions uncomment the following line and remove these
+  # comments:
+  # disable_ddl_transaction!
+
+  def change
+    add_column :merge_request_metrics, :latest_build_started_at, :datetime
+    add_column :merge_request_metrics, :latest_build_finished_at, :datetime
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
-ActiveRecord::Schema.define(version: 20160901141443) do
+ActiveRecord::Schema.define(version: 20160915081353) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -442,6 +442,7 @@ ActiveRecord::Schema.define(version: 20160901141443) do
     t.datetime "first_added_to_board_at"
     t.datetime "created_at",                         null: false
     t.datetime "updated_at",                         null: false
+    t.datetime "first_mentioned_in_commit_at"
   end
   add_index "issue_metrics", ["issue_id"], name: "index_issue_metrics", using: :btree
@@ -596,6 +597,9 @@ ActiveRecord::Schema.define(version: 20160901141443) do
     t.datetime "first_closed_at"
     t.datetime "created_at",                               null: false
     t.datetime "updated_at",                               null: false
+    t.datetime "first_deployed_to_production_at"
+    t.datetime "latest_build_started_at"
+    t.datetime "latest_build_finished_at"
   end
   add_index "merge_request_metrics", ["merge_request_id"], name: "index_merge_request_metrics", using: :btree
@@ -641,6 +645,13 @@ ActiveRecord::Schema.define(version: 20160901141443) do
   add_index "merge_requests", ["title"], name: "index_merge_requests_on_title", using: :btree
   add_index "merge_requests", ["title"], name: "index_merge_requests_on_title_trigram", using: :gin, opclasses: {"title"=>"gin_trgm_ops"}
+  create_table "merge_requests_closing_issues", force: :cascade do |t|
+    t.integer  "merge_request_id", null: false
+    t.integer  "issue_id",         null: false
+    t.datetime "created_at",       null: false
+    t.datetime "updated_at",       null: false
+  end
+
   create_table "milestones", force: :cascade do |t|
     t.string   "title",       null: false
     t.integer  "project_id",  null: false
@@ -1170,6 +1181,8 @@ ActiveRecord::Schema.define(version: 20160901141443) do
   add_foreign_key "lists", "boards"
   add_foreign_key "lists", "labels"
   add_foreign_key "merge_request_metrics", "merge_requests"
+  add_foreign_key "merge_requests_closing_issues", "issues"
+  add_foreign_key "merge_requests_closing_issues", "merge_requests"
   add_foreign_key "personal_access_tokens", "users"
   add_foreign_key "protected_branch_merge_access_levels", "protected_branches"
   add_foreign_key "protected_branch_push_access_levels", "protected_branches"