Fix vacuum scheduler missing lock, locks never expiring (mastodon#19458)

Remove vacuuming of orphaned preview cards

app/lib/vacuum/media_attachments_vacuum.rb

@@ -8,8 +8,8 @@ def initialize(retention_period)
   end
 
   def perform
-    vacuum_cached_files! if retention_period?
     vacuum_orphaned_records!
+    vacuum_cached_files! if retention_period?
   end
 
   private

app/lib/vacuum/preview_cards_vacuum.rb

@@ -9,7 +9,6 @@ def initialize(retention_period)
 
   def perform
     vacuum_cached_images! if retention_period?
-    vacuum_orphaned_records!
   end
 
   private
@@ -21,18 +20,10 @@ def vacuum_cached_images!
     end
   end
 
-  def vacuum_orphaned_records!
-    orphaned_preview_cards.in_batches.destroy_all
-  end
-
   def preview_cards_past_retention_period
     PreviewCard.cached.where(PreviewCard.arel_table[:updated_at].lt(@retention_period.ago))
   end
 
-  def orphaned_preview_cards
-    PreviewCard.where('NOT EXISTS (SELECT 1 FROM preview_cards_statuses WHERE preview_cards_statuses.preview_card_id = preview_cards.id)').where(PreviewCard.arel_table[:created_at].lt(TTL.ago))
-  end
-
   def retention_period?
     @retention_period.present?
   end

app/workers/scheduler/vacuum_scheduler.rb

@@ -3,7 +3,7 @@
 class Scheduler::VacuumScheduler
   include Sidekiq::Worker
 
-  sidekiq_options retry: 0
+  sidekiq_options retry: 0, lock: :until_executed
 
   def perform
     vacuum_operations.each do |operation|

config/initializers/sidekiq.rb

@@ -35,4 +35,5 @@
   config.reaper_count    = 1000
   config.reaper_interval = 600
   config.reaper_timeout  = 150
+  config.lock_ttl        = 50.days.to_i
 end

spec/lib/vacuum/preview_cards_vacuum_spec.rb

@@ -28,9 +28,5 @@
     it 'does not delete attached preview cards' do
       expect(new_preview_card.reload).to be_persisted
     end
-
-    it 'deletes preview cards not attached to any status' do
-      expect { orphaned_preview_card.reload }.to raise_error ActiveRecord::RecordNotFound
-    end
   end
 end