Load user records in batches.

app/jobs/regular/notify_mailing_list_subscribers.rb

@@ -33,7 +33,7 @@ module Jobs
                      WHERE cu.category_id = ? AND cu.user_id = users.id AND cu.notification_level = ?
                   )', post.topic.category_id, CategoryUser.notification_levels[:muted])
 
-      users.each do |user|
+      users.find_each do |user|
         if Guardian.new(user).can_see?(post)
           if EmailLog.reached_max_emails?(user)
             skip(user.email, user.id, post.id, I18n.t('email_log.exceeded_emails_limit'))