Disable LinkLfsObjects background migration

Some jobs are timing out and failing on staging.gitlab.com. This
also disables the post deploy migration scheduling the background
migration.

https://sentry.gitlab.net/gitlab/staginggitlabcom/issues/1306635/events/latest/

db/post_migrate/20200210062432_schedule_link_lfs_objects.rb

@@ -4,32 +4,11 @@ class ScheduleLinkLfsObjects < ActiveRecord::Migration[6.0]
   include Gitlab::Database::MigrationHelpers
 
   DOWNTIME = false
-  MIGRATION = 'LinkLfsObjects'
-  BATCH_SIZE = 1_000
 
   disable_ddl_transaction!
 
-  class Project < ActiveRecord::Base
-    include EachBatch
-
-    self.table_name = 'projects'
-  end
-
   def up
-    fork_network_members =
-      Gitlab::BackgroundMigration::LinkLfsObjects::ForkNetworkMember
-        .select(1)
-        .with_non_existing_lfs_objects
-        .where('fork_network_members.project_id = projects.id')
-
-    forks = Project.where('EXISTS (?)', fork_network_members)
-
-    queue_background_migration_jobs_by_range_at_intervals(
-      forks,
-      MIGRATION,
-      BackgroundMigrationWorker.minimum_interval,
-      batch_size: BATCH_SIZE
-    )
+    # no-op as background migration being schedule times out in some instances
   end
 
   def down

lib/gitlab/background_migration/link_lfs_objects.rb

@@ -24,24 +24,7 @@ module Gitlab
       end
 
       def perform(start_id, end_id)
-        select_query =
-          ForkNetworkMember
-            .select('lop.lfs_object_id, fork_network_members.project_id')
-            .with_non_existing_lfs_objects
-            .where(project_id: start_id..end_id)
-
-        return if select_query.empty?
-
-        execute <<-SQL
-          INSERT INTO lfs_objects_projects (lfs_object_id, project_id)
-          #{select_query.to_sql}
-        SQL
-      end
-
-      private
-
-      def execute(sql)
-        ::ActiveRecord::Base.connection.execute(sql)
+        # no-op as some queries times out
       end
     end
   end

spec/lib/gitlab/background_migration/link_lfs_objects_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-
-describe Gitlab::BackgroundMigration::LinkLfsObjects, :migration, schema: 2020_02_10_062432 do
-  let(:namespaces) { table(:namespaces) }
-  let(:projects) { table(:projects) }
-  let(:fork_networks) { table(:fork_networks) }
-  let(:fork_network_members) { table(:fork_network_members) }
-  let(:lfs_objects) { table(:lfs_objects) }
-  let(:lfs_objects_projects) { table(:lfs_objects_projects) }
-  let(:namespace) { namespaces.create(name: 'GitLab', path: 'gitlab') }
-  let(:source_project) { projects.create(namespace_id: namespace.id) }
-  let(:another_source_project) { projects.create(namespace_id: namespace.id) }
-  let(:project) { projects.create(namespace_id: namespace.id) }
-  let(:another_project) { projects.create(namespace_id: namespace.id) }
-  let(:other_project) { projects.create(namespace_id: namespace.id) }
-  let(:linked_project) { projects.create(namespace_id: namespace.id) }
-  let(:fork_network) { fork_networks.create(root_project_id: source_project.id) }
-  let(:another_fork_network) { fork_networks.create(root_project_id: another_source_project.id) }
-  let(:lfs_object) { lfs_objects.create(oid: 'abc123', size: 100) }
-  let(:another_lfs_object) { lfs_objects.create(oid: 'def456', size: 200) }
-
-  before do
-    # Create links between projects
-    fork_network_members.create(fork_network_id: fork_network.id, project_id: source_project.id, forked_from_project_id: nil)
-
-    [project, another_project, linked_project].each do |p|
-      fork_network_members.create(
-        fork_network_id: fork_network.id,
-        project_id: p.id,
-        forked_from_project_id: fork_network.root_project_id
-      )
-    end
-
-    fork_network_members.create(fork_network_id: another_fork_network.id, project_id: another_source_project.id, forked_from_project_id: nil)
-    fork_network_members.create(fork_network_id: another_fork_network.id, project_id: other_project.id, forked_from_project_id: another_fork_network.root_project_id)
-
-    # Links LFS objects to some projects
-    [source_project, another_source_project, linked_project].each do |p|
-      lfs_objects_projects.create(lfs_object_id: lfs_object.id, project_id: p.id)
-      lfs_objects_projects.create(lfs_object_id: another_lfs_object.id, project_id: p.id)
-    end
-  end
-
-  it 'creates LfsObjectsProject records for forks within the specified range of project IDs' do
-    expect { subject.perform(project.id, other_project.id) }.to change { lfs_objects_projects.count }.by(6)
-
-    expect(lfs_object_ids_for(project)).to match_array(lfs_object_ids_for(source_project))
-    expect(lfs_object_ids_for(another_project)).to match_array(lfs_object_ids_for(source_project))
-    expect(lfs_object_ids_for(other_project)).to match_array(lfs_object_ids_for(another_source_project))
-
-    expect { subject.perform(project.id, other_project.id) }.not_to change { lfs_objects_projects.count }
-  end
-
-  context 'when it is not necessary to create LfsObjectProject records' do
-    it 'does not create LfsObjectProject records' do
-      expect { subject.perform(linked_project.id, linked_project.id) }
-        .not_to change { lfs_objects_projects.count }
-    end
-  end
-
-  def lfs_object_ids_for(project)
-    lfs_objects_projects.where(project_id: project.id).pluck(:lfs_object_id)
-  end
-end

spec/migrations/schedule_link_lfs_objects_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-require Rails.root.join('db', 'post_migrate', '20200210062432_schedule_link_lfs_objects.rb')
-
-describe ScheduleLinkLfsObjects, :migration, :sidekiq do
-  let(:namespaces) { table(:namespaces) }
-  let(:projects) { table(:projects) }
-  let(:fork_networks) { table(:fork_networks) }
-  let(:fork_network_members) { table(:fork_network_members) }
-  let(:lfs_objects) { table(:lfs_objects) }
-  let(:lfs_objects_projects) { table(:lfs_objects_projects) }
-  let(:namespace) { namespaces.create(name: 'GitLab', path: 'gitlab') }
-  let(:fork_network) { fork_networks.create(root_project_id: source_project.id) }
-  let(:another_fork_network) { fork_networks.create(root_project_id: another_source_project.id) }
-  let(:source_project) { projects.create(namespace_id: namespace.id) }
-  let(:another_source_project) { projects.create(namespace_id: namespace.id) }
-  let(:project) { projects.create(namespace_id: namespace.id) }
-  let(:another_project) { projects.create(namespace_id: namespace.id) }
-  let(:other_project) { projects.create(namespace_id: namespace.id) }
-  let(:linked_project) { projects.create(namespace_id: namespace.id) }
-  let(:lfs_object) { lfs_objects.create(oid: 'abc123', size: 100) }
-  let(:another_lfs_object) { lfs_objects.create(oid: 'def456', size: 200) }
-
-  before do
-    # Create links between projects
-    fork_network_members.create(fork_network_id: fork_network.id, project_id: source_project.id, forked_from_project_id: nil)
-
-    [project, another_project, linked_project].each do |p|
-      fork_network_members.create(
-        fork_network_id: fork_network.id,
-        project_id: p.id,
-        forked_from_project_id: fork_network.root_project_id
-      )
-    end
-
-    fork_network_members.create(fork_network_id: another_fork_network.id, project_id: another_source_project.id, forked_from_project_id: nil)
-    fork_network_members.create(fork_network_id: another_fork_network.id, project_id: other_project.id, forked_from_project_id: another_fork_network.root_project_id)
-  end
-
-  context 'when there are forks to be backfilled' do
-    before do
-      stub_const("#{described_class.name}::BATCH_SIZE", 2)
-
-      # Links LFS objects to some projects
-      [source_project, another_source_project, linked_project].each do |p|
-        lfs_objects_projects.create(lfs_object_id: lfs_object.id, project_id: p.id)
-        lfs_objects_projects.create(lfs_object_id: another_lfs_object.id, project_id: p.id)
-      end
-    end
-
-    it 'schedules background migration to link LFS objects' do
-      Sidekiq::Testing.fake! do
-        migrate!
-
-        expect(BackgroundMigrationWorker.jobs.size).to eq(2)
-        expect(described_class::MIGRATION)
-          .to be_scheduled_delayed_migration(2.minutes, project.id, another_project.id)
-        expect(described_class::MIGRATION)
-          .to be_scheduled_delayed_migration(4.minutes, other_project.id, other_project.id)
-      end
-    end
-  end
-
-  context 'when there are no forks to be backfilled' do
-    before do
-      # Links LFS objects to all projects
-      projects.all.each do |p|
-        lfs_objects_projects.create(lfs_object_id: lfs_object.id, project_id: p.id)
-        lfs_objects_projects.create(lfs_object_id: another_lfs_object.id, project_id: p.id)
-      end
-    end
-
-    it 'does not schedule any job' do
-      Sidekiq::Testing.fake! do
-        migrate!
-
-        expect(BackgroundMigrationWorker.jobs.size).to eq(0)
-      end
-    end
-  end
-end