Merge branch '245263-mr-refs-cleanup-scheduler' into 'master'

Schedule clean up of merge request refs efficiently

See merge request gitlab-org/gitlab!46758

app/models/merge_request.rb

@@ -56,6 +56,7 @@ class MergeRequest < ApplicationRecord
 
   has_one :merge_request_diff,
     -> { order('merge_request_diffs.id DESC') }, inverse_of: :merge_request
+  has_one :cleanup_schedule, inverse_of: :merge_request
 
   belongs_to :latest_merge_request_diff, class_name: 'MergeRequestDiff'
   manual_inverse_association :latest_merge_request_diff, :merge_request

app/models/merge_request/cleanup_schedule.rb

+# frozen_string_literal: true
+
+class MergeRequest::CleanupSchedule < ApplicationRecord
+  belongs_to :merge_request, inverse_of: :cleanup_schedule
+
+  validates :scheduled_at, presence: true
+
+  def self.scheduled_merge_request_ids(limit)
+    where('completed_at IS NULL AND scheduled_at <= NOW()')
+      .order('scheduled_at DESC')
+      .limit(limit)
+      .pluck(:merge_request_id)
+  end
+end

app/services/merge_requests/cleanup_refs_service.rb

@@ -9,7 +9,7 @@ module MergeRequests
     attr_reader :merge_request
 
     def self.schedule(merge_request)
-      MergeRequestCleanupRefsWorker.perform_in(TIME_THRESHOLD, merge_request.id)
+      merge_request.create_cleanup_schedule(scheduled_at: TIME_THRESHOLD.from_now)
     end
 
     def initialize(merge_request)
@@ -22,6 +22,7 @@ module MergeRequests
     end
 
     def execute
+      return error("Merge request is not scheduled to be cleaned up yet.") unless scheduled?
       return error("Merge request has not been closed nor merged for #{TIME_THRESHOLD.inspect}.") unless eligible?
 
       # Ensure that commit shas of refs are kept around so we won't lose them when GC runs.
@@ -31,6 +32,9 @@ module MergeRequests
       return error('Failed to cache merge ref sha.') unless cache_merge_ref_sha
 
       delete_refs
+
+      return error('Failed to update schedule.') unless update_schedule
+
       success
     end
 
@@ -38,6 +42,10 @@ module MergeRequests
 
     attr_reader :repository, :ref_path, :merge_ref_path, :ref_head_sha, :merge_ref_sha
 
+    def scheduled?
+      merge_request.cleanup_schedule.present? && merge_request.cleanup_schedule.scheduled_at <= Time.current
+    end
+
     def eligible?
       return met_time_threshold?(merge_request.metrics&.latest_closed_at) if merge_request.closed?
 
@@ -71,5 +79,9 @@ module MergeRequests
     def delete_refs
       repository.delete_refs(ref_path, merge_ref_path)
     end
+
+    def update_schedule
+      merge_request.cleanup_schedule.update(completed_at: Time.current)
+    end
   end
 end

app/services/merge_requests/reopen_service.rb

@@ -15,6 +15,7 @@ module MergeRequests
         invalidate_cache_counts(merge_request, users: merge_request.assignees)
         merge_request.update_project_counter_caches
         merge_request.cache_merge_request_closes_issues!(current_user)
+        merge_request.cleanup_schedule&.destroy
       end
 
       merge_request

app/workers/all_queues.yml

@@ -379,6 +379,14 @@
   :weight: 1
   :idempotent:
   :tags: []
+- :name: cronjob:schedule_merge_request_cleanup_refs
+  :feature_category: :source_code_management
+  :has_external_dependencies:
+  :urgency: :low
+  :resource_boundary: :unknown
+  :weight: 1
+  :idempotent: true
+  :tags: []
 - :name: cronjob:schedule_migrate_external_diffs
   :feature_category: :source_code_management
   :has_external_dependencies:

app/workers/schedule_merge_request_cleanup_refs_worker.rb

+# frozen_string_literal: true
+
+class ScheduleMergeRequestCleanupRefsWorker
+  include ApplicationWorker
+  include CronjobQueue # rubocop:disable Scalability/CronWorkerContext
+
+  feature_category :source_code_management
+  idempotent!
+
+  # Based on existing data, MergeRequestCleanupRefsWorker can run 3 jobs per
+  # second. This means that 180 jobs can be performed but since there are some
+  # spikes from time time, it's better to give it some allowance.
+  LIMIT = 180
+  DELAY = 10.seconds
+  BATCH_SIZE = 30
+
+  def perform
+    return if Gitlab::Database.read_only?
+
+    ids = MergeRequest::CleanupSchedule.scheduled_merge_request_ids(LIMIT).map { |id| [id] }
+
+    MergeRequestCleanupRefsWorker.bulk_perform_in(DELAY, ids, batch_size: BATCH_SIZE) # rubocop:disable Scalability/BulkPerformWithContext
+
+    log_extra_metadata_on_done(:merge_requests_count, ids.size)
+  end
+end

changelogs/unreleased/245263-mr-refs-cleanup-scheduler.yml

+---
+title: Schedule clean up of merge request refs efficiently
+merge_request: 46758
+author:
+type: performance

config/initializers/1_settings.rb

@@ -531,6 +531,9 @@ Settings.cron_jobs['analytics_instance_statistics_count_job_trigger_worker']['jo
 Settings.cron_jobs['member_invitation_reminder_emails_worker'] ||= Settingslogic.new({})
 Settings.cron_jobs['member_invitation_reminder_emails_worker']['cron'] ||= '0 0 * * *'
 Settings.cron_jobs['member_invitation_reminder_emails_worker']['job_class'] = 'MemberInvitationReminderEmailsWorker'
+Settings.cron_jobs['schedule_merge_request_cleanup_refs_worker'] ||= Settingslogic.new({})
+Settings.cron_jobs['schedule_merge_request_cleanup_refs_worker']['cron'] ||= '* * * * *'
+Settings.cron_jobs['schedule_merge_request_cleanup_refs_worker']['job_class'] = 'ScheduleMergeRequestCleanupRefsWorker'
 
 Gitlab.ee do
   Settings.cron_jobs['active_user_count_threshold_worker'] ||= Settingslogic.new({})

db/migrate/20201023114628_create_merge_request_cleanup_schedules.rb

+# frozen_string_literal: true
+
+class CreateMergeRequestCleanupSchedules < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def up
+    with_lock_retries do
+      create_table :merge_request_cleanup_schedules, id: false do |t|
+        t.references :merge_request, primary_key: true, index: { unique: true }, null: false, foreign_key: { on_delete: :cascade }
+        t.datetime_with_timezone :scheduled_at, null: false
+        t.datetime_with_timezone :completed_at, null: true
+
+        t.timestamps_with_timezone
+
+        t.index :scheduled_at, where: 'completed_at IS NULL', name: 'index_mr_cleanup_schedules_timestamps'
+      end
+    end
+  end
+
+  def down
+    with_lock_retries do
+      drop_table :merge_request_cleanup_schedules
+    end
+  end
+end

db/schema_migrations/20201023114628

+f4fb466c74e1366d5980a54d6e5fc42fe78237cae33d8cdaf5573d2fe75f8a5a
\ No newline at end of file

db/structure.sql

@@ -13463,6 +13463,23 @@ CREATE SEQUENCE merge_request_blocks_id_seq
 
 ALTER SEQUENCE merge_request_blocks_id_seq OWNED BY merge_request_blocks.id;
 
+CREATE TABLE merge_request_cleanup_schedules (
+    merge_request_id bigint NOT NULL,
+    scheduled_at timestamp with time zone NOT NULL,
+    completed_at timestamp with time zone,
+    created_at timestamp with time zone NOT NULL,
+    updated_at timestamp with time zone NOT NULL
+);
+
+CREATE SEQUENCE merge_request_cleanup_schedules_merge_request_id_seq
+    START WITH 1
+    INCREMENT BY 1
+    NO MINVALUE
+    NO MAXVALUE
+    CACHE 1;
+
+ALTER SEQUENCE merge_request_cleanup_schedules_merge_request_id_seq OWNED BY merge_request_cleanup_schedules.merge_request_id;
+
 CREATE TABLE merge_request_context_commit_diff_files (
     sha bytea NOT NULL,
     relative_order integer NOT NULL,
@@ -17934,6 +17951,8 @@ ALTER TABLE ONLY merge_request_assignees ALTER COLUMN id SET DEFAULT nextval('me
 
 ALTER TABLE ONLY merge_request_blocks ALTER COLUMN id SET DEFAULT nextval('merge_request_blocks_id_seq'::regclass);
 
+ALTER TABLE ONLY merge_request_cleanup_schedules ALTER COLUMN merge_request_id SET DEFAULT nextval('merge_request_cleanup_schedules_merge_request_id_seq'::regclass);
+
 ALTER TABLE ONLY merge_request_context_commits ALTER COLUMN id SET DEFAULT nextval('merge_request_context_commits_id_seq'::regclass);
 
 ALTER TABLE ONLY merge_request_diff_details ALTER COLUMN merge_request_diff_id SET DEFAULT nextval('merge_request_diff_details_merge_request_diff_id_seq'::regclass);
@@ -19146,6 +19165,9 @@ ALTER TABLE ONLY merge_request_assignees
 ALTER TABLE ONLY merge_request_blocks
     ADD CONSTRAINT merge_request_blocks_pkey PRIMARY KEY (id);
 
+ALTER TABLE ONLY merge_request_cleanup_schedules
+    ADD CONSTRAINT merge_request_cleanup_schedules_pkey PRIMARY KEY (merge_request_id);
+
 ALTER TABLE ONLY merge_request_context_commits
     ADD CONSTRAINT merge_request_context_commits_pkey PRIMARY KEY (id);
 
@@ -21086,6 +21108,8 @@ CREATE INDEX index_merge_request_assignees_on_user_id ON merge_request_assignees
 
 CREATE INDEX index_merge_request_blocks_on_blocked_merge_request_id ON merge_request_blocks USING btree (blocked_merge_request_id);
 
+CREATE UNIQUE INDEX index_merge_request_cleanup_schedules_on_merge_request_id ON merge_request_cleanup_schedules USING btree (merge_request_id);
+
 CREATE INDEX index_merge_request_diff_commits_on_sha ON merge_request_diff_commits USING btree (sha);
 
 CREATE INDEX index_merge_request_diff_details_on_merge_request_diff_id ON merge_request_diff_details USING btree (merge_request_diff_id);
@@ -21200,6 +21224,8 @@ CREATE INDEX index_mirror_data_on_next_execution_and_retry_count ON project_mirr
 
 CREATE UNIQUE INDEX index_mr_blocks_on_blocking_and_blocked_mr_ids ON merge_request_blocks USING btree (blocking_merge_request_id, blocked_merge_request_id);
 
+CREATE INDEX index_mr_cleanup_schedules_timestamps ON merge_request_cleanup_schedules USING btree (scheduled_at) WHERE (completed_at IS NULL);
+
 CREATE UNIQUE INDEX index_mr_context_commits_on_merge_request_id_and_sha ON merge_request_context_commits USING btree (merge_request_id, sha);
 
 CREATE UNIQUE INDEX index_namespace_aggregation_schedules_on_namespace_id ON namespace_aggregation_schedules USING btree (namespace_id);
@@ -23961,6 +23987,9 @@ ALTER TABLE ONLY project_error_tracking_settings
 ALTER TABLE ONLY list_user_preferences
     ADD CONSTRAINT fk_rails_916d72cafd FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE;
 
+ALTER TABLE ONLY merge_request_cleanup_schedules
+    ADD CONSTRAINT fk_rails_92dd0e705c FOREIGN KEY (merge_request_id) REFERENCES merge_requests(id) ON DELETE CASCADE;
+
 ALTER TABLE ONLY board_labels
     ADD CONSTRAINT fk_rails_9374a16edd FOREIGN KEY (board_id) REFERENCES boards(id) ON DELETE CASCADE;
 

spec/factories/merge_request_cleanup_schedules.rb

+# frozen_string_literal: true
+
+FactoryBot.define do
+  factory :merge_request_cleanup_schedule, class: 'MergeRequest::CleanupSchedule' do
+    merge_request
+    scheduled_at { Time.current }
+  end
+end

spec/lib/gitlab/import_export/all_models.yml

@@ -179,6 +179,7 @@ merge_requests:
 - user_mentions
 - system_note_metadata
 - note_authors
+- cleanup_schedule
 external_pull_requests:
 - project
 merge_request_diff:
@@ -195,6 +196,8 @@ merge_request_diff_files:
 merge_request_context_commits:
 - merge_request
 - diff_files
+cleanup_schedule:
+- merge_request
 ci_pipelines:
 - project
 - user

spec/lib/gitlab/import_export/safe_model_attributes.yml

@@ -878,3 +878,9 @@ PushRule:
   - reject_unsigned_commits
   - commit_committer_check
   - regexp_uses_re2
+MergeRequest::CleanupSchedule:
+- id
+- scheduled_at
+- completed_at
+- created_at
+- updated_at

spec/models/merge_request/cleanup_schedule_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe MergeRequest::CleanupSchedule do
+  describe 'associations' do
+    it { is_expected.to belong_to(:merge_request) }
+  end
+
+  describe 'validations' do
+    it { is_expected.to validate_presence_of(:scheduled_at) }
+  end
+
+  describe '.scheduled_merge_request_ids' do
+    let_it_be(:mr_cleanup_schedule_1) { create(:merge_request_cleanup_schedule, scheduled_at: 2.days.ago) }
+    let_it_be(:mr_cleanup_schedule_2) { create(:merge_request_cleanup_schedule, scheduled_at: 1.day.ago) }
+    let_it_be(:mr_cleanup_schedule_3) { create(:merge_request_cleanup_schedule, scheduled_at: 1.day.ago, completed_at: Time.current) }
+    let_it_be(:mr_cleanup_schedule_4) { create(:merge_request_cleanup_schedule, scheduled_at: 4.days.ago) }
+    let_it_be(:mr_cleanup_schedule_5) { create(:merge_request_cleanup_schedule, scheduled_at: 3.days.ago) }
+    let_it_be(:mr_cleanup_schedule_6) { create(:merge_request_cleanup_schedule, scheduled_at: 1.day.from_now) }
+    let_it_be(:mr_cleanup_schedule_7) { create(:merge_request_cleanup_schedule, scheduled_at: 5.days.ago) }
+
+    it 'only includes incomplete schedule within the specified limit' do
+      expect(described_class.scheduled_merge_request_ids(4)).to eq([
+        mr_cleanup_schedule_2.merge_request_id,
+        mr_cleanup_schedule_1.merge_request_id,
+        mr_cleanup_schedule_5.merge_request_id,
+        mr_cleanup_schedule_4.merge_request_id
+      ])
+    end
+  end
+end

spec/models/merge_request_spec.rb

@@ -30,6 +30,7 @@ RSpec.describe MergeRequest, factory_default: :keep do
     it { is_expected.to have_many(:resource_state_events) }
     it { is_expected.to have_many(:draft_notes) }
     it { is_expected.to have_many(:reviews).inverse_of(:merge_request) }
+    it { is_expected.to have_one(:cleanup_schedule).inverse_of(:merge_request) }
 
     context 'for forks' do
       let!(:project) { create(:project) }

spec/services/merge_requests/cleanup_refs_service_spec.rb

@@ -4,14 +4,15 @@ require 'spec_helper'
 
 RSpec.describe MergeRequests::CleanupRefsService do
   describe '.schedule' do
-    let(:merge_request) { build(:merge_request) }
-
-    it 'schedules MergeRequestCleanupRefsWorker' do
-      expect(MergeRequestCleanupRefsWorker)
-        .to receive(:perform_in)
-        .with(described_class::TIME_THRESHOLD, merge_request.id)
+    let(:merge_request) { create(:merge_request) }
 
+    it 'creates a merge request cleanup schedule' do
+      freeze_time do
         described_class.schedule(merge_request)
+
+        expect(merge_request.reload.cleanup_schedule.scheduled_at)
+          .to eq(described_class::TIME_THRESHOLD.from_now)
+      end
     end
   end
 
@@ -20,6 +21,8 @@ RSpec.describe MergeRequests::CleanupRefsService do
       # Need to re-enable this as it's being stubbed in spec_helper for
       # performance reasons but is needed to run for this test.
       allow(Gitlab::Git::KeepAround).to receive(:execute).and_call_original
+
+      merge_request.create_cleanup_schedule(scheduled_at: described_class::TIME_THRESHOLD.ago)
     end
 
     subject(:result) { described_class.new(merge_request).execute }
@@ -32,6 +35,7 @@ RSpec.describe MergeRequests::CleanupRefsService do
           expect(result[:status]).to eq(:success)
           expect(kept_around?(old_ref_head)).to be_truthy
           expect(ref_head).to be_nil
+          expect(merge_request.cleanup_schedule.completed_at).to be_present
         end
       end
 
@@ -43,6 +47,7 @@ RSpec.describe MergeRequests::CleanupRefsService do
 
         it 'does not fail' do
           expect(result[:status]).to eq(:success)
+          expect(merge_request.cleanup_schedule.completed_at).to be_present
         end
       end
 
@@ -85,6 +90,31 @@ RSpec.describe MergeRequests::CleanupRefsService do
 
         it_behaves_like 'service that does not clean up merge request refs'
       end
+
+      context 'when cleanup schedule fails to update' do
+        before do
+          allow(merge_request.cleanup_schedule).to receive(:update).and_return(false)
+        end
+
+        it 'creates keep around ref and deletes merge request refs' do
+          old_ref_head = ref_head
+
+          aggregate_failures do
+            expect(result[:status]).to eq(:error)
+            expect(kept_around?(old_ref_head)).to be_truthy
+            expect(ref_head).to be_nil
+            expect(merge_request.cleanup_schedule.completed_at).not_to be_present
+          end
+        end
+      end
+
+      context 'when merge request is not scheduled to be cleaned up yet' do
+        before do
+          merge_request.cleanup_schedule.update!(scheduled_at: 1.day.from_now)
+        end
+
+        it_behaves_like 'service that does not clean up merge request refs'
+      end
     end
 
     shared_examples_for 'service that does not clean up merge request refs' do
@@ -92,6 +122,7 @@ RSpec.describe MergeRequests::CleanupRefsService do
         aggregate_failures do
           expect(result[:status]).to eq(:error)
           expect(ref_head).to be_present
+          expect(merge_request.cleanup_schedule.completed_at).not_to be_present
         end
       end
     end

spec/services/merge_requests/reopen_service_spec.rb

@@ -23,6 +23,7 @@ RSpec.describe MergeRequests::ReopenService do
 
       before do
         allow(service).to receive(:execute_hooks)
+        merge_request.create_cleanup_schedule(scheduled_at: Time.current)
 
         perform_enqueued_jobs do
           service.execute(merge_request)
@@ -43,6 +44,10 @@ RSpec.describe MergeRequests::ReopenService do
         expect(email.subject).to include(merge_request.title)
       end
 
+      it 'destroys cleanup schedule record' do
+        expect(merge_request.reload.cleanup_schedule).to be_nil
+      end
+
       context 'note creation' do
         it 'creates resource state event about merge_request reopen' do
           event = merge_request.resource_state_events.last

spec/workers/schedule_merge_request_cleanup_refs_worker_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe ScheduleMergeRequestCleanupRefsWorker do
+  subject(:worker) { described_class.new }
+
+  describe '#perform' do
+    before do
+      allow(MergeRequest::CleanupSchedule)
+        .to receive(:scheduled_merge_request_ids)
+        .with(described_class::LIMIT)
+        .and_return([1, 2, 3, 4])
+    end
+
+    it 'does nothing if the database is read-only' do
+      allow(Gitlab::Database).to receive(:read_only?).and_return(true)
+      expect(MergeRequestCleanupRefsWorker).not_to receive(:bulk_perform_in)
+
+      worker.perform
+    end
+
+    include_examples 'an idempotent worker' do
+      it 'schedules MergeRequestCleanupRefsWorker to be performed by batch' do
+        expect(MergeRequestCleanupRefsWorker)
+          .to receive(:bulk_perform_in)
+          .with(
+            described_class::DELAY,
+            [[1], [2], [3], [4]],
+            batch_size: described_class::BATCH_SIZE
+          )
+
+        expect(worker).to receive(:log_extra_metadata_on_done).with(:merge_requests_count, 4)
+
+        worker.perform
+      end
+    end
+  end
+end