Update usages of files_max_capacity

Because there are now 4 models replicated by SSF. This is still a rough
stopgap, but it does not have to be 100% accurate since the behavior of
the system with different capacity numbers depends on the implementation
details as well as the particular characteristics of the deployment. The
main thing we need to resolve soon is that snippet repositories syncs
are limited by "files max capacity" instead of "repositories max
capacity". But that change is probably not as trivial as this one, so I
have opened a follow up issue:
https://gitlab.com/gitlab-org/gitlab/-/issues/294074

ee/app/workers/geo/file_download_dispatch_worker.rb

@@ -20,7 +20,9 @@ module Geo
     end
 
     def max_capacity
-      current_node.files_max_capacity
+      # Transition-period-solution.
+      # Explained in https://gitlab.com/gitlab-org/gitlab/-/issues/213872#note_336828581
+      [current_node.files_max_capacity / 2, 1].max
     end
 
     def schedule_job(object_type, object_db_id)

ee/app/workers/geo/registry_sync_worker.rb

@@ -19,7 +19,7 @@ module Geo
     def max_capacity
       # Transition-period-solution.
       # Explained in https://gitlab.com/gitlab-org/gitlab/-/issues/213872#note_336828581
-      [current_node.files_max_capacity / 4, 1].max
+      [current_node.files_max_capacity / 2, 1].max
     end
 
     def schedule_job(replicable_name, model_record_id)

ee/changelogs/unreleased/mk-update-sync-capacity.yml

+---
+title: 'Geo: Update usages of files_max_capacity'
+merge_request: 50190
+author:
+type: changed

ee/spec/workers/geo/file_download_dispatch_worker_spec.rb

@@ -51,7 +51,7 @@ RSpec.describe Geo::FileDownloadDispatchWorker, :geo, :use_sql_query_cache_for_t
     create(:geo_lfs_object_registry, :failed, lfs_object: lfs_object_2)
 
     stub_const('Geo::Scheduler::SchedulerWorker::DB_RETRIEVE_BATCH_SIZE', 5)
-    secondary.update!(files_max_capacity: 2)
+    secondary.update!(files_max_capacity: 4)
     allow(Gitlab::SidekiqStatus).to receive(:job_status).with([]).and_return([]).twice
     allow(Gitlab::SidekiqStatus).to receive(:job_status).with(%w[123 456]).and_return([true, true], [true, true], [false, false])
 
@@ -70,7 +70,7 @@ RSpec.describe Geo::FileDownloadDispatchWorker, :geo, :use_sql_query_cache_for_t
     create(:geo_lfs_object_registry, :never_synced, lfs_object: lfs_object_3)
 
     stub_const('Geo::Scheduler::SchedulerWorker::DB_RETRIEVE_BATCH_SIZE', 3)
-    secondary.update!(files_max_capacity: 3)
+    secondary.update!(files_max_capacity: 6)
 
     expect(Geo::FileDownloadWorker).to receive(:perform_async).with('lfs', lfs_object_1.id).once do
       Thread.new do
@@ -368,7 +368,7 @@ RSpec.describe Geo::FileDownloadDispatchWorker, :geo, :use_sql_query_cache_for_t
   # 2. We send 2, wait for 1 to finish, and then send again.
   it 'attempts to load a new batch without pending downloads' do
     stub_const('Geo::Scheduler::SchedulerWorker::DB_RETRIEVE_BATCH_SIZE', 5)
-    secondary.update!(files_max_capacity: 2)
+    secondary.update!(files_max_capacity: 4)
     result_object = double(:result, success: true, bytes_downloaded: 100, primary_missing_file: false)
     allow_any_instance_of(::Gitlab::Geo::Replication::BaseTransfer).to receive(:download_from_primary).and_return(result_object)
 

ee/spec/workers/geo/registry_sync_worker_spec.rb

@@ -44,7 +44,7 @@ RSpec.describe Geo::RegistrySyncWorker, :geo, :use_sql_query_cache_for_tracking_
     package_file_2 = create(:geo_package_file_registry)
 
     stub_const('Geo::Scheduler::SchedulerWorker::DB_RETRIEVE_BATCH_SIZE', 5)
-    secondary.update!(files_max_capacity: 8)
+    secondary.update!(files_max_capacity: 4)
     allow(Gitlab::SidekiqStatus).to receive(:job_status).with([]).and_return([]).twice
     allow(Gitlab::SidekiqStatus).to receive(:job_status).with(array_including('123', '456')).and_return([true, true], [true, true], [false, false])
 
@@ -69,7 +69,7 @@ RSpec.describe Geo::RegistrySyncWorker, :geo, :use_sql_query_cache_for_tracking_
     # We retrieve all the items in a single batch
     stub_const('Geo::Scheduler::SchedulerWorker::DB_RETRIEVE_BATCH_SIZE', 2)
     # 8 / 4 = 2 We use one quarter of common files_max_capacity in the Geo::RegistrySyncWorker
-    secondary.update!(files_max_capacity: 8)
+    secondary.update!(files_max_capacity: 4)
 
     expect(Geo::EventWorker).to receive(:perform_async).with('package_file', :created, { model_record_id: package_file_1.package_file.id }).once do
       Thread.new do
@@ -92,7 +92,7 @@ RSpec.describe Geo::RegistrySyncWorker, :geo, :use_sql_query_cache_for_tracking_
   it 'attempts to load a new batch without pending downloads' do
     stub_const('Geo::Scheduler::SchedulerWorker::DB_RETRIEVE_BATCH_SIZE', 5)
     # 8 / 4 = 2 We use one quarter of common files_max_capacity in the Geo::RegistrySyncWorker
-    secondary.update!(files_max_capacity: 8)
+    secondary.update!(files_max_capacity: 4)
 
     result_object = double(
       :result,