Improve performance of finding last deployed environment

app/controllers/projects/blob_controller.rb

@@ -31,7 +31,7 @@ class Projects::BlobController < Projects::ApplicationController
   def show
     branch_name = @ref if @repository.branch_exists?(@ref)
-    @environment = @project.latest_environment_for(@commit, ref: branch_name)
+    @environment = @project.environments_for(commit: @commit, ref: branch_name).last
     @environment = nil unless can?(current_user, :read_environment, @environment)
   end

app/controllers/projects/commit_controller.rb

@@ -96,7 +96,7 @@ class Projects::CommitController < Projects::ApplicationController
     @diffs = commit.diffs(opts)
     @notes_count = commit.notes.count
-    @environment = @project.latest_environment_for(@commit)
+    @environment = @project.environments_for(commit: @commit).last
     @environment = nil unless can?(current_user, :read_environment, @environment)
   end

app/controllers/projects/compare_controller.rb

@@ -58,7 +58,7 @@ class Projects::CompareController < Projects::ApplicationController
       @diffs = @compare.diffs(diff_options)
       branch_name = @head_ref if @repository.branch_exists?(@head_ref)
-      @environment = @project.latest_environment_for(@commit, ref: branch_name)
+      @environment = @project.environments_for(commit: @commit, ref: branch_name).last
       @environment = nil unless can?(current_user, :read_environment, @environment)
       @diff_notes_disabled = true

app/controllers/projects/environments_controller.rb

@@ -10,7 +10,7 @@ class Projects::EnvironmentsController < Projects::ApplicationController
   def index
     @scope = params[:scope]
-    @environments = project.environments
+    @environments = project.environments.includes(:last_deployment)
     respond_to do |format|
       format.html

app/controllers/projects/merge_requests_controller.rb

@@ -103,7 +103,7 @@ class Projects::MergeRequestsController < Projects::ApplicationController
       end
     end
-    @environment = @merge_request.latest_environment
+    @environment = @merge_request.environments.last
     @environment = nil unless can?(current_user, :read_environment, @environment)
     respond_to do |format|
@@ -248,7 +248,7 @@ class Projects::MergeRequestsController < Projects::ApplicationController
                  end
         @diff_notes_disabled = true
-        @environment = @merge_request.latest_environment
+        @environment = @merge_request.environments.last
         @environment = nil unless can?(current_user, :read_environment, @environment)
         render json: { html: view_to_html_string('projects/merge_requests/_new_diffs', diffs: @diffs, environment: @environment) }

app/models/ci/build.rb

@@ -9,6 +9,7 @@ module Ci
     belongs_to :erased_by, class_name: 'User'
     has_many :deployments, as: :deployable
+    has_one :last_deployment, -> { order('deployments.id DESC') }, as: :deployable, class_name: 'Deployment'
     # The "environment" field for builds is a String, and is the unexpanded name
     def persisted_environment
@@ -183,10 +184,6 @@ module Ci
       success? && !last_deployment.try(:last?)
     end
-    def last_deployment
-      deployments.last
-    end
-
     def depends_on_builds
       # Get builds of the same type
       latest_builds = self.pipeline.builds.latest

app/models/environment.rb

@@ -6,7 +6,8 @@ class Environment < ActiveRecord::Base
   belongs_to :project, required: true, validate: true
-  has_many :deployments
+  has_many :deployments, dependent: :destroy
+  has_one :last_deployment, -> { order('deployments.id DESC') }, class_name: 'Deployment'
   before_validation :nullify_external_url
   before_validation :generate_slug, if: ->(env) { env.slug.blank? }
@@ -37,6 +38,7 @@ class Environment < ActiveRecord::Base
   scope :available, -> { with_state(:available) }
   scope :stopped, -> { with_state(:stopped) }
+  scope :order_by_last_deployed_at, -> { order(Gitlab::Database.nulls_first_order('(SELECT MAX(id) FROM deployments WHERE deployments.environment_id = environments.id)', 'ASC')) }
   state_machine :state, initial: :available do
     event :start do
@@ -51,14 +53,6 @@ class Environment < ActiveRecord::Base
     state :stopped
   end
-  def self.latest_for_commit(environments, commit)
-    environments.sort_by do |environment|
-      deployment = environment.first_deployment_for(commit)
-
-      deployment.try(:created_at) || DateTime.parse('1970-01-01')
-    end.last
-  end
-
   def predefined_variables
     [
       { key: 'CI_ENVIRONMENT_NAME', value: name, public: true },
@@ -70,10 +64,6 @@ class Environment < ActiveRecord::Base
     ref.to_s == last_deployment.try(:ref)
   end
-  def last_deployment
-    deployments.last
-  end
-
   def nullify_external_url
     self.external_url = nil if self.external_url.blank?
   end
@@ -95,6 +85,10 @@ class Environment < ActiveRecord::Base
     last_deployment.includes_commit?(commit)
   end
+  def last_deployed_at
+    last_deployment.try(:created_at)
+  end
+
   def update_merge_request_metrics?
     (environment_type || name) == "production"
   end

app/models/merge_request.rb

@@ -720,21 +720,15 @@ class MergeRequest < ActiveRecord::Base
     @environments ||= begin
       target_envs = target_project.environments_for(
-        target_branch, commit: diff_head_commit, with_tags: true)
+        ref: target_branch, commit: diff_head_commit, with_tags: true)
       source_envs = source_project.environments_for(
-        source_branch, commit: diff_head_commit) if source_project
+        ref: source_branch, commit: diff_head_commit) if source_project
       (target_envs.to_a + source_envs.to_a).uniq
     end
   end
-  def latest_environment
-    return @latest_environment if defined?(@latest_environment)
-
-    @latest_environment = Environment.latest_for_commit(environments, diff_head_commit)
-  end
-
   def state_human_name
     if merged?
       "Merged"

app/models/project.rb

@@ -1306,7 +1306,7 @@ class Project < ActiveRecord::Base
     Gitlab::Redis.with { |redis| redis.del(pushes_since_gc_redis_key) }
   end
-  def environments_for(ref, commit: nil, with_tags: false)
+  def environments_for(ref: nil, commit: nil, with_tags: false)
     deps =
       if ref
         deployments_query = with_tags ? 'ref = ? OR tag IS TRUE' : 'ref = ?'
@@ -1322,22 +1322,17 @@ class Project < ActiveRecord::Base
       .select(:environment_id)
     environments_found = environments.available
-      .where(id: environment_ids).to_a
-    return environments_found unless commit
+      .where(id: environment_ids).order_by_last_deployed_at.to_a
+    return environments_found unless ref && commit
     environments_found.select do |environment|
       environment.includes_commit?(commit)
     end
   end
-  def latest_environment_for(commit, ref: nil)
-    environments = environments_for(ref, commit: commit)
-    Environment.latest_for_commit(environments, commit)
-  end
-
   def environments_recently_updated_on_branch(branch)
-    environments_for(branch).select do |environment|
+    environments_for(ref: branch).select do |environment|
       environment.recently_updated_on_branch?(branch)
     end
   end

app/models/repository.rb

@@ -1190,6 +1190,7 @@ class Repository
   def route_map_for(sha)
     blob = blob_at(sha, ROUTE_MAP_PATH)
     return unless blob
+    
     blob.load_all_data!(self)
     blob.data
   end
@@ -1197,6 +1198,7 @@ class Repository
   def gitlab_ci_yml_for(sha)
     blob = blob_at(sha, GITLAB_CI_YML_PATH)
     return unless blob
+
     blob.load_all_data!(self)
     blob.data
   end

lib/gitlab/database.rb

@@ -35,6 +35,20 @@ module Gitlab
       order
     end
+    def self.nulls_first_order(field, direction = 'ASC')
+      order = "#{field} #{direction}"
+
+      if Gitlab::Database.postgresql?
+        order << ' NULLS FIRST'
+      else
+        # `field IS NULL` will be `0` for non-NULL columns and `1` for NULL
+        # columns. In the (default) ascending order, `0` comes first.
+        order.prepend("#{field} IS NULL, ") if direction == 'DESC'
+      end
+
+      order
+    end
+
     def self.random
       Gitlab::Database.postgresql? ? "RANDOM()" : "RAND()"
     end

spec/lib/gitlab/database_spec.rb

@@ -55,6 +55,22 @@ describe Gitlab::Database, lib: true do
     end
   end
+  describe '.nulls_first_order' do
+    context 'when using PostgreSQL' do
+      before { expect(described_class).to receive(:postgresql?).and_return(true) }
+
+      it { expect(described_class.nulls_first_order('column', 'ASC')).to eq 'column ASC NULLS FIRST'}
+      it { expect(described_class.nulls_first_order('column', 'DESC')).to eq 'column DESC NULLS FIRST'}
+    end
+
+    context 'when using MySQL' do
+      before { expect(described_class).to receive(:postgresql?).and_return(false) }
+
+      it { expect(described_class.nulls_first_order('column', 'ASC')).to eq 'column ASC'}
+      it { expect(described_class.nulls_first_order('column', 'DESC')).to eq 'column IS NULL, column DESC'}
+    end
+  end
+
   describe '#true_value' do
     it 'returns correct value for PostgreSQL' do
       expect(described_class).to receive(:postgresql?).and_return(true)

spec/models/environment_spec.rb

@@ -22,22 +22,17 @@ describe Environment, models: true do
   it { is_expected.to validate_length_of(:external_url).is_at_most(255) }
   it { is_expected.to validate_uniqueness_of(:external_url).scoped_to(:project_id) }
-  describe '.latest_for_commit' do
+  describe '.order_by_last_deployed_at' do
+    let(:project) { create(:project) }
     let!(:environment1) { create(:environment, project: project) }
     let!(:environment2) { create(:environment, project: project) }
     let!(:environment3) { create(:environment, project: project) }
-    let!(:deployment1) { create(:deployment, environment: environment1) }
     let!(:deployment2) { create(:deployment, environment: environment2) }
-    let(:commit) { RepoHelpers.sample_commit }
-
-    before do
-      allow(environment1).to receive(:first_deployment_for).with(commit).and_return(deployment1)
-      allow(environment2).to receive(:first_deployment_for).with(commit).and_return(deployment2)
-      allow(environment3).to receive(:first_deployment_for).with(commit).and_return(nil)
-    end
-    it 'returns the environment that the commit was last deployed to' do
-      expect(Environment.latest_for_commit([environment1, environment2, environment3], commit)).to be(environment2)
+    let!(:deployment1) { create(:deployment, environment: environment1) }
+    it 'returns the environments in order of having been last deployed' do
+      # byebug
+      expect(project.environments.order_by_last_deployed_at.to_a).to eq([environment3, environment2, environment1])
     end
   end

spec/models/merge_request_spec.rb

@@ -1069,30 +1069,6 @@ describe MergeRequest, models: true do
     end
   end
-  describe '#latest_environment' do
-    let(:project) { subject.project }
-    let!(:environment1) { create(:environment, project: project) }
-    let!(:environment2) { create(:environment, project: project) }
-    let!(:environment3) { create(:environment, project: project) }
-    let!(:deployment1) { create(:deployment, environment: environment1, ref: 'master', sha: commit.id) }
-    let!(:deployment2) { create(:deployment, environment: environment2, ref: 'feature', sha: commit.id) }
-    let(:commit) { subject.diff_head_commit }
-
-    before do
-      allow(environment1).to receive(:first_deployment_for).with(commit).and_return(deployment1)
-      allow(environment2).to receive(:first_deployment_for).with(commit).and_return(deployment2)
-      allow(environment3).to receive(:first_deployment_for).with(commit).and_return(nil)
-    end
-
-    before do
-      allow(subject).to receive(:environments).and_return([environment1, environment2, environment3])
-    end
-
-    it 'returns the environment that the commit was last deployed to' do
-      expect(subject.latest_environment).to eq(environment2)
-    end
-  end
-
   describe "#reload_diff" do
     let(:note) { create(:diff_note_on_merge_request, project: subject.project, noteable: subject) }

spec/models/project_spec.rb

@@ -1726,17 +1726,17 @@ describe Project, models: true do
       end
       it 'returns environment when with_tags is set' do
-        expect(project.environments_for('master', commit: project.commit, with_tags: true))
+        expect(project.environments_for(ref: 'master', commit: project.commit, with_tags: true))
           .to contain_exactly(environment)
       end
       it 'does not return environment when no with_tags is set' do
-        expect(project.environments_for('master', commit: project.commit))
+        expect(project.environments_for(ref: 'master', commit: project.commit))
           .to be_empty
       end
       it 'does not return environment when commit is not part of deployment' do
-        expect(project.environments_for('master', commit: project.commit('feature')))
+        expect(project.environments_for(ref: 'master', commit: project.commit('feature')))
           .to be_empty
       end
     end
@@ -1747,22 +1747,22 @@ describe Project, models: true do
       end
       it 'returns environment when ref is set' do
-        expect(project.environments_for('master', commit: project.commit))
+        expect(project.environments_for(ref: 'master', commit: project.commit))
           .to contain_exactly(environment)
       end
       it 'does not environment when ref is different' do
-        expect(project.environments_for('feature', commit: project.commit))
+        expect(project.environments_for(ref: 'feature', commit: project.commit))
           .to be_empty
       end
       it 'does not return environment when commit is not part of deployment' do
-        expect(project.environments_for('master', commit: project.commit('feature')))
+        expect(project.environments_for(ref: 'master', commit: project.commit('feature')))
           .to be_empty
       end
       it 'returns environment when commit constraint is not set' do
-        expect(project.environments_for('master'))
+        expect(project.environments_for(ref: 'master'))
           .to contain_exactly(environment)
       end
     end
@@ -1773,48 +1773,12 @@ describe Project, models: true do
       end
       it 'returns environment' do
-        expect(project.environments_for(nil, commit: project.commit))
+        expect(project.environments_for(commit: project.commit))
           .to contain_exactly(environment)
       end
     end
   end
-  describe '#latest_environment_for' do
-    let(:project) { create(:project) }
-    let!(:environment1) { create(:environment, project: project) }
-    let!(:environment2) { create(:environment, project: project) }
-    let!(:environment3) { create(:environment, project: project) }
-    let!(:deployment1) { create(:deployment, environment: environment1, ref: 'master', sha: commit.id) }
-    let!(:deployment2) { create(:deployment, environment: environment2, ref: 'feature', sha: commit.id) }
-    let(:commit) { project.commit }
-
-    before do
-      allow(environment1).to receive(:first_deployment_for).with(commit).and_return(deployment1)
-      allow(environment2).to receive(:first_deployment_for).with(commit).and_return(deployment2)
-      allow(environment3).to receive(:first_deployment_for).with(commit).and_return(nil)
-    end
-
-    context 'when specifying a ref' do
-      before do
-        allow(project).to receive(:environments_for).with('master', commit: commit).and_return([environment1])
-      end
-
-      it 'returns the environment that the commit was last deployed to from that ref' do
-        expect(project.latest_environment_for(commit, ref: 'master')).to eq(environment1)
-      end
-    end
-
-    context 'when not specifying a ref' do
-      before do
-        allow(project).to receive(:environments_for).with(nil, commit: commit).and_return([environment1, environment2])
-      end
-
-      it 'returns the environment that the commit was last deployed to' do
-        expect(project.latest_environment_for(commit)).to eq(environment2)
-      end
-    end
-  end
-
   describe '#environments_recently_updated_on_branch' do
     let(:project) { create(:project, :repository) }
     let(:environment) { create(:environment, project: project) }