Backfill `member_namespace_id` for `GroupMember`

For `GroupMembers`, the `member_namespace_id` ==
`source_id`.  Copy this over.  `ProjectMember` will be handled
in another migration.

Changelog: changed

db/migrate/20220120211831_temp_index_for_group_namespace_member_backfill.rb

+# frozen_string_literal: true
+
+class TempIndexForGroupNamespaceMemberBackfill < Gitlab::Database::Migration[1.0]
+  INDEX_NAME = 'tmp_index_for_namespace_id_migration_on_group_members'
+
+  disable_ddl_transaction!
+
+  def up
+    # Temporary index to be removed in 14.10
+    # https://gitlab.com/gitlab-org/gitlab/-/issues/353538
+    add_concurrent_index :members, :id, where: "members.member_namespace_id IS NULL and members.type = 'GroupMember'", name: INDEX_NAME
+  end
+
+  def down
+    remove_concurrent_index_by_name :members, INDEX_NAME
+  end
+end

db/post_migrate/20220120211832_backfill_member_namespace_id_for_group_members.rb

+# frozen_string_literal: true
+
+class BackfillMemberNamespaceIdForGroupMembers < Gitlab::Database::Migration[1.0]
+  MIGRATION = 'BackfillMemberNamespaceForGroupMembers'
+  INTERVAL = 2.minutes
+  BATCH_SIZE = 1_000
+  MAX_BATCH_SIZE = 2_000
+  SUB_BATCH_SIZE = 100
+
+  def up
+    queue_batched_background_migration(
+      MIGRATION,
+      :members,
+      :id,
+      job_interval: INTERVAL,
+      batch_size: BATCH_SIZE,
+      max_batch_size: MAX_BATCH_SIZE,
+      sub_batch_size: SUB_BATCH_SIZE
+    )
+  end
+
+  def down
+    Gitlab::Database::BackgroundMigration::BatchedMigration
+      .for_configuration(MIGRATION, :members, :id, [])
+      .delete_all
+  end
+end

db/schema_migrations/20220120211831

+68b45f97a2165c934f097ca976fb27ffcb533c57facee95344e3985b5cfd8347
\ No newline at end of file

db/schema_migrations/20220120211832

+dd3a4209a72b470a14a3acc5d06db1f5fec67cb4f19b20b2e4d7d94b302fe122
\ No newline at end of file

db/structure.sql

@@ -28479,6 +28479,8 @@ CREATE INDEX tmp_idx_vulnerability_occurrences_on_id_where_report_type_7_99 ON v
 
 CREATE INDEX tmp_index_container_repositories_on_id_migration_state ON container_repositories USING btree (id, migration_state);
 
+CREATE INDEX tmp_index_for_namespace_id_migration_on_group_members ON members USING btree (id) WHERE ((member_namespace_id IS NULL) AND ((type)::text = 'GroupMember'::text));
+
 CREATE INDEX tmp_index_for_namespace_id_migration_on_routes ON routes USING btree (id) WHERE ((namespace_id IS NULL) AND ((source_type)::text = 'Namespace'::text));
 
 CREATE INDEX tmp_index_members_on_state ON members USING btree (state) WHERE (state = 2);

lib/gitlab/background_migration/backfill_member_namespace_for_group_members.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module BackgroundMigration
+    # Backfills the `members.member_namespace_id` column for `type=GroupMember`
+    class BackfillMemberNamespaceForGroupMembers
+      include Gitlab::Database::DynamicModelHelpers
+
+      def perform(start_id, end_id, batch_table, batch_column, sub_batch_size, pause_ms)
+        parent_batch_relation = relation_scoped_to_range(batch_table, batch_column, start_id, end_id)
+
+        parent_batch_relation.each_batch(column: batch_column, of: sub_batch_size) do |sub_batch|
+          batch_metrics.time_operation(:update_all) do
+            sub_batch.update_all('member_namespace_id=source_id')
+          end
+
+          pause_ms = [0, pause_ms].max
+          sleep(pause_ms * 0.001)
+        end
+      end
+
+      def batch_metrics
+        @batch_metrics ||= Gitlab::Database::BackgroundMigration::BatchMetrics.new
+      end
+
+      private
+
+      def relation_scoped_to_range(source_table, source_key_column, start_id, stop_id)
+        define_batchable_model(source_table, connection: ActiveRecord::Base.connection)
+          .joins('INNER JOIN namespaces ON members.source_id = namespaces.id')
+          .where(source_key_column => start_id..stop_id)
+          .where(type: 'GroupMember')
+          .where(source_type: 'Namespace')
+          .where(member_namespace_id: nil)
+      end
+    end
+  end
+end

spec/lib/gitlab/background_migration/backfill_member_namespace_for_group_members_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::BackgroundMigration::BackfillMemberNamespaceForGroupMembers, :migration, schema: 20220120211832 do
+  let(:migration) { described_class.new }
+  let(:members_table) { table(:members) }
+  let(:namespaces_table) { table(:namespaces) }
+
+  let(:table_name) { 'members' }
+  let(:batch_column) { :id }
+  let(:sub_batch_size) { 100 }
+  let(:pause_ms) { 0 }
+
+  subject(:perform_migration) { migration.perform(1, 10, table_name, batch_column, sub_batch_size, pause_ms) }
+
+  before do
+    namespaces_table.create!(id: 100, name: 'test1', path: 'test1', type: 'Group')
+    namespaces_table.create!(id: 101, name: 'test2', path: 'test2', type: 'Group')
+    namespaces_table.create!(id: 102, name: 'test3', path: 'test3', type: 'Group')
+    namespaces_table.create!(id: 201, name: 'test4', path: 'test4', type: 'Project')
+
+    members_table.create!(id: 1, source_id: 100, source_type: 'Namespace', type: 'GroupMember', member_namespace_id: nil, access_level: 10, notification_level: 3)
+    members_table.create!(id: 2, source_id: 101, source_type: 'Namespace', type: 'GroupMember', member_namespace_id: nil, access_level: 10, notification_level: 3)
+    members_table.create!(id: 3, source_id: 102, source_type: 'Namespace', type: 'GroupMember', member_namespace_id: 102, access_level: 10, notification_level: 3)
+    members_table.create!(id: 4, source_id: 103, source_type: 'Project', type: 'ProjectMember', member_namespace_id: nil, access_level: 10, notification_level: 3)
+    members_table.create!(id: 5, source_id: 104, source_type: 'Project', type: 'ProjectMember', member_namespace_id: 201, access_level: 10, notification_level: 3)
+  end
+
+  it 'backfills `member_namespace_id` for the selected records', :aggregate_failures do
+    expect(members_table.where(type: 'GroupMember', member_namespace_id: nil).count).to eq 2
+    expect(members_table.where(type: 'ProjectMember', member_namespace_id: nil).count).to eq 1
+
+    queries = ActiveRecord::QueryRecorder.new do
+      perform_migration
+    end
+
+    expect(queries.count).to eq(3)
+    expect(members_table.where(type: 'GroupMember', member_namespace_id: nil).count).to eq 0
+    expect(members_table.where(type: 'GroupMember').pluck(:member_namespace_id)).to match_array([100, 101, 102])
+    expect(members_table.where(type: 'ProjectMember', member_namespace_id: nil).count).to eq 1
+    expect(members_table.where(type: 'ProjectMember').pluck(:member_namespace_id)).to match_array([nil, 201])
+  end
+
+  it 'tracks timings of queries' do
+    expect(migration.batch_metrics.timings).to be_empty
+
+    expect { perform_migration }.to change { migration.batch_metrics.timings }
+  end
+end

spec/migrations/backfill_member_namespace_id_for_group_members_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+require_migration!
+
+RSpec.describe BackfillMemberNamespaceIdForGroupMembers do
+  let_it_be(:migration) { described_class::MIGRATION }
+
+  describe '#up' do
+    it 'schedules background jobs for each batch of group members' do
+      migrate!
+
+      expect(migration).to have_scheduled_batched_migration(
+        table_name: :members,
+        column_name: :id,
+        interval: described_class::INTERVAL
+      )
+    end
+  end
+
+  describe '#down' do
+    it 'deletes all batched migration records' do
+      migrate!
+      schema_migrate_down!
+
+      expect(migration).not_to have_scheduled_batched_migration
+    end
+  end
+end