Clean up wrong max_seats_used batch two

First batch of wrong max_seats_used cleanup was done by a previous MR
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/78107.
This MR is the second batch, which aims to clean up all remaining ones.

https://gitlab.com/gitlab-org/gitlab/-/merge_requests/78107 has covered
gitlab_subscriptions with start_date >= 02-Aug-2021. This MR covers
gitlab_subscriptions with start_date < 02-Aug-2021.

Changelog: fixed

db/post_migrate/20220212120735_schedule_fix_incorrect_max_seats_used2.rb

+# frozen_string_literal: true
+
+class ScheduleFixIncorrectMaxSeatsUsed2 < Gitlab::Database::Migration[1.0]
+  MIGRATION = 'FixIncorrectMaxSeatsUsed'
+  TMP_IDX_NAME = 'tmp_gitlab_subscriptions_max_seats_used_migration_2'
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :gitlab_subscriptions, :id, where: "start_date < '2021-08-02' AND max_seats_used != 0 AND max_seats_used > seats_in_use AND max_seats_used > seats", name: TMP_IDX_NAME
+
+    return unless Gitlab.com?
+
+    migrate_in(1.hour, MIGRATION, ['batch_2_for_start_date_before_02_aug_2021'])
+  end
+
+  def down
+    remove_concurrent_index_by_name :gitlab_subscriptions, TMP_IDX_NAME
+  end
+end

db/schema_migrations/20220212120735

+c075ee9d6efeae4b7a9b6e310f0c3d0bdd0ac6a58dc214427d4de9ae579db50d
\ No newline at end of file

db/structure.sql

@@ -28355,6 +28355,8 @@ CREATE UNIQUE INDEX term_agreements_unique_index ON term_agreements USING btree
 
 CREATE INDEX tmp_gitlab_subscriptions_max_seats_used_migration ON gitlab_subscriptions USING btree (id) WHERE ((start_date >= '2021-08-02'::date) AND (start_date <= '2021-11-20'::date) AND (max_seats_used <> 0) AND (max_seats_used > seats_in_use) AND (max_seats_used > seats));
 
+CREATE INDEX tmp_gitlab_subscriptions_max_seats_used_migration_2 ON gitlab_subscriptions USING btree (id) WHERE ((start_date < '2021-08-02'::date) AND (max_seats_used <> 0) AND (max_seats_used > seats_in_use) AND (max_seats_used > seats));
+
 CREATE INDEX tmp_idx_vulnerability_occurrences_on_id_where_report_type_7_99 ON vulnerability_occurrences USING btree (id) WHERE (report_type = ANY (ARRAY[7, 99]));
 
 CREATE INDEX tmp_index_container_repositories_on_id_migration_state ON container_repositories USING btree (id, migration_state);

ee/lib/ee/gitlab/background_migration/fix_incorrect_max_seats_used.rb

@@ -97,8 +97,14 @@ module EE
 
         BATCH_SIZE = 200
 
-        def perform
-          eligible_gitlab_subscriptions.find_each(batch_size: BATCH_SIZE) do |gs|
+        def perform(batch = nil)
+          gitlab_subscriptions = if batch == 'batch_2_for_start_date_before_02_aug_2021'
+                                   eligible_gitlab_subscriptions_batch_2
+                                 else
+                                   eligible_gitlab_subscriptions
+                                 end
+
+          gitlab_subscriptions.find_each(batch_size: BATCH_SIZE) do |gs|
             gs_histories = gs.gitlab_subscription_histories.to_a.sort_by { |gh| gh.id }
             gs_histories << gs
 
@@ -170,10 +176,10 @@ module EE
         end
 
         def eligible_gitlab_subscriptions
-          # Only search subscriptions with `start_date` in range `['2-Aug-2021', '20-Nov-2021']` because:
-          #   - for subscriptions with `start_date < '2-Aug-2021'`, we do not enable QSR(Quarterly Subscription Reconciliation)
-          #   - for subscriptions with `start_date > '20-Nov-2021'`, they should not have such issue
-          #     because the MR https://gitlab.com/gitlab-org/gitlab/-/merge_requests/73078 was merged on `09-Nov-2021`.
+          # Only search subscriptions with `start_date` in range `['2021-08-02', '2021-11-20']` because:
+          #   - for subscriptions with `start_date < '2021-08-02'`, we do not enable QSR(Quarterly Subscription Reconciliation)
+          #   - for subscriptions with `start_date > '2021-11-20'`, they should not have such issue
+          #     because the MR https://gitlab.com/gitlab-org/gitlab/-/merge_requests/73078 was merged on `2021-11-09`.
           #     All rails nodes should have deployed new merged code within 10 days.
           #
           # Only need to check if max_seats_used is not 0
@@ -181,8 +187,21 @@ module EE
           # Only need to check if max_seats_used > seats (zuora subscription quantity)
 
           GitlabSubscription.preload(:namespace, :hosted_plan, :gitlab_subscription_histories)
-            .where('gitlab_subscriptions.start_date >= ?', Date.parse('2-Aug-2021'))
-            .where('gitlab_subscriptions.start_date <= ?', Date.parse('20-Nov-2021'))
+            .where('gitlab_subscriptions.start_date >= ?', Date.parse('2021-08-02'))
+            .where('gitlab_subscriptions.start_date <= ?', Date.parse('2021-11-20'))
+            .where.not(max_seats_used: 0)
+            .where('gitlab_subscriptions.max_seats_used > gitlab_subscriptions.seats_in_use')
+            .where('gitlab_subscriptions.max_seats_used > gitlab_subscriptions.seats')
+        end
+
+        def eligible_gitlab_subscriptions_batch_2
+          # Only search subscriptions with `start_date < '2021-08-02'`
+          # Only need to check if max_seats_used is not 0
+          # Only need to check if max_seats_used > seats_in_use
+          # Only need to check if max_seats_used > seats (zuora subscription quantity)
+
+          GitlabSubscription.preload(:namespace, :hosted_plan, :gitlab_subscription_histories)
+            .where('gitlab_subscriptions.start_date < ?', Date.parse('2021-08-02'))
             .where.not(max_seats_used: 0)
             .where('gitlab_subscriptions.max_seats_used > gitlab_subscriptions.seats_in_use')
             .where('gitlab_subscriptions.max_seats_used > gitlab_subscriptions.seats')

ee/spec/lib/ee/gitlab/background_migration/fix_incorrect_max_seats_used_spec.rb

@@ -14,7 +14,7 @@ RSpec.describe Gitlab::BackgroundMigration::FixIncorrectMaxSeatsUsed, :saas do
     let(:max_seats_used) { 10 }
     let(:seats_owed) { [0, max_seats_used - seats].max }
 
-    let(:start_date) { Date.parse('10-Nov-2021') }
+    let(:start_date) { Date.parse('2021-11-10') }
     let(:end_date) { start_date + 1.year }
 
     let(:keep_old_seats_attributes_after_renew) { true }
@@ -91,30 +91,58 @@ RSpec.describe Gitlab::BackgroundMigration::FixIncorrectMaxSeatsUsed, :saas do
         include_examples 'does not reset max_seats_used and seats_owed'
       end
 
-      context 'when start_date is before 2-Aug-2021' do
-        let(:start_date) { Date.parse('1-Aug-2021') }
+      context 'when start_date is before 2021-08-02' do
+        let(:start_date) { Date.parse('2021-08-01') }
 
         include_examples 'does not reset max_seats_used and seats_owed'
       end
 
-      context 'when start_date is 2-Aug-2021' do
-        let(:start_date) { Date.parse('2-Aug-2021') }
+      context 'when start_date is 2021-08-02' do
+        let(:start_date) { Date.parse('2021-08-02') }
 
         include_examples 'resets max_seats_used and seats_owed'
       end
 
-      context 'when start_date is 20-Nov-2021' do
-        let(:start_date) { Date.parse('20-Nov-2021') }
+      context 'when start_date is 2021-11-20' do
+        let(:start_date) { Date.parse('2021-11-20') }
 
         include_examples 'resets max_seats_used and seats_owed'
       end
 
-      context 'when start_date is after 20-Nov-2021' do
-        let(:start_date) { Date.parse('21-Nov-2021') }
+      context 'when start_date is after 2021-11-20' do
+        let(:start_date) { Date.parse('2021-11-21') }
 
         include_examples 'does not reset max_seats_used and seats_owed'
       end
 
+      context 'when batch_2_for_start_date_before_02_aug_2021' do
+        def perform_and_reload
+          migration.perform(batch)
+
+          gitlab_subscription.reload
+        end
+
+        let(:batch) { 'batch_2_for_start_date_before_02_aug_2021' }
+
+        context 'when start_date is before 2021-08-02' do
+          let(:start_date) { Date.parse('2021-08-01') }
+
+          include_examples 'resets max_seats_used and seats_owed'
+        end
+
+        context 'when start_date is 2021-08-02' do
+          let(:start_date) { Date.parse('2021-08-02') }
+
+          include_examples 'does not reset max_seats_used and seats_owed'
+        end
+
+        context 'when start_date is after 2021-08-02' do
+          let(:start_date) { Date.parse('2021-08-03') }
+
+          include_examples 'does not reset max_seats_used and seats_owed'
+        end
+      end
+
       context 'when max_seats_used is 0' do
         let(:max_seats_used) { 0 }
 

lib/gitlab/background_migration/fix_incorrect_max_seats_used.rb

@@ -4,7 +4,7 @@ module Gitlab
   module BackgroundMigration
     # rubocop: disable Style/Documentation
     class FixIncorrectMaxSeatsUsed
-      def perform
+      def perform(batch = nil)
       end
     end
   end

spec/migrations/schedule_fix_incorrect_max_seats_used2_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+require_migration!
+
+RSpec.describe ScheduleFixIncorrectMaxSeatsUsed2, :migration do
+  let(:migration_name) { described_class::MIGRATION.to_s.demodulize }
+
+  describe '#up' do
+    it 'schedules a job on Gitlab.com' do
+      allow(Gitlab).to receive(:com?).and_return(true)
+
+      Sidekiq::Testing.fake! do
+        freeze_time do
+          migrate!
+
+          expect(migration_name).to be_scheduled_delayed_migration(1.hour, 'batch_2_for_start_date_before_02_aug_2021')
+          expect(BackgroundMigrationWorker.jobs.size).to eq(1)
+        end
+      end
+    end
+
+    it 'does not schedule any jobs when not Gitlab.com' do
+      allow(Gitlab).to receive(:com?).and_return(false)
+
+      Sidekiq::Testing.fake! do
+        migrate!
+
+        expect(migration_name).not_to be_scheduled_delayed_migration
+        expect(BackgroundMigrationWorker.jobs.size).to eq(0)
+      end
+    end
+  end
+end