Create post deploy migration to populate has_vulnerabilities

db/post_migrate/20201103192526_schedule_populate_has_vulnerabilities.rb

+# frozen_string_literal: true
+
+class SchedulePopulateHasVulnerabilities < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  BATCH_SIZE = 1_000
+  DELAY_INTERVAL = 2.minutes
+  MIGRATION_CLASS = 'PopulateHasVulnerabilities'
+
+  disable_ddl_transaction!
+
+  def up
+    Gitlab::BackgroundMigration::PopulateHasVulnerabilities::Vulnerability.distinct.each_batch(of: BATCH_SIZE, column: :project_id) do |batch, index|
+      project_ids = batch.pluck(:project_id)
+
+      migrate_in(index * DELAY_INTERVAL, MIGRATION_CLASS, project_ids)
+    end
+  end
+
+  def down
+    # no-op
+  end
+end

db/schema_migrations/20201103192526

+bb137c3a41a40e740f8ae65b43d7f9218f52d6d5eaf53c8a64b3336a8f16141b
\ No newline at end of file

spec/migrations/schedule_populate_has_vulnerabilities_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+require_migration!
+
+RSpec.describe SchedulePopulateHasVulnerabilities do
+  let(:users) { table(:users) }
+  let(:namespaces) { table(:namespaces) }
+  let(:projects) { table(:projects) }
+  let(:vulnerabilities) { table(:vulnerabilities) }
+  let(:user) { users.create!(name: 'test', email: 'test@example.com', projects_limit: 5) }
+  let(:namespace) { namespaces.create!(name: 'gitlab', path: 'gitlab-org') }
+  let(:vulnerability_base_params) { { title: 'title', state: 2, severity: 0, confidence: 5, report_type: 2, author_id: user.id } }
+  let!(:project_1) { projects.create!(namespace_id: namespace.id, name: 'foo_1') }
+  let!(:project_2) { projects.create!(namespace_id: namespace.id, name: 'foo_2') }
+  let!(:project_3) { projects.create!(namespace_id: namespace.id, name: 'foo_3') }
+
+  around do |example|
+    freeze_time { Sidekiq::Testing.fake! { example.run } }
+  end
+
+  before do
+    stub_const("#{described_class.name}::BATCH_SIZE", 1)
+
+    vulnerabilities.create!(vulnerability_base_params.merge(project_id: project_1.id))
+    vulnerabilities.create!(vulnerability_base_params.merge(project_id: project_3.id))
+  end
+
+  it 'schedules the background jobs', :aggregate_failures do
+    migrate!
+
+    expect(BackgroundMigrationWorker.jobs.size).to be(2)
+    expect(described_class::MIGRATION_CLASS).to be_scheduled_delayed_migration(2.minutes, project_1.id)
+    expect(described_class::MIGRATION_CLASS).to be_scheduled_delayed_migration(4.minutes, project_3.id)
+  end
+end