perf: improve contact delete performance

app/models/contact.rb

@@ -137,7 +137,7 @@ class Contact < ApplicationRecord
       .where('contacts.phone_number IS NULL OR contacts.phone_number = ?', '')
       .where('contacts.identifier IS NULL OR contacts.identifier = ?', '')
       .where('contacts.created_at < ?', time_period)
-      .where.missing(:conversations)
+      .where('NOT EXISTS (SELECT 1 FROM conversations WHERE conversations.contact_id = contacts.id)')
   }
 
   def get_source_id(inbox_id)

app/services/internal/remove_stale_contacts_service.rb

@@ -2,18 +2,31 @@ class Internal::RemoveStaleContactsService
   pattr_initialize [:account!]
 
   def perform(batch_size = 1000)
-    contacts_to_remove = @account.contacts.stale_without_conversations(30.days.ago)
-    total_deleted = 0
-
     Rails.logger.info "[Internal::RemoveStaleContactsService] Starting removal of stale contacts for account #{@account.id}"
 
-    contacts_to_remove.find_in_batches(batch_size: batch_size) do |batch|
-      contact_ids = batch.map(&:id)
+    # Get the stale contacts query
+    stale_contacts = @account.contacts.stale_without_conversations(30.days.ago)
 
+    total_deleted = 0
+
+    # Get only IDs in batches without loading full records
+    stale_contacts.select(:id).in_batches(of: batch_size) do |relation|
+      # Use pluck to get only the IDs
+      contact_ids = relation.pluck(:id)
+      next if contact_ids.empty?
+
+      # Delete associated contact_inboxes first
       ContactInbox.where(contact_id: contact_ids).delete_all
+
+      # Then delete the contacts
       Contact.where(id: contact_ids).delete_all
-      total_deleted += batch.size
-      Rails.logger.info "[Internal::RemoveStaleContactsService] Deleted #{batch.size} contacts (#{total_deleted} total) for account #{@account.id}"
+
+      total_deleted += contact_ids.size
+      Rails.logger.info "[Internal::RemoveStaleContactsService] Deleted #{contact_ids.size} contacts " \
+                        "(#{total_deleted} total) for account #{@account.id}"
     end
+
+    Rails.logger.info "[Internal::RemoveStaleContactsService] Completed removal of #{total_deleted} stale contacts " \
+                      "for account #{@account.id}"
   end
 end