From f4902421eaa50dea98dc5046848f95c959cb3c88 Mon Sep 17 00:00:00 2001
From: Benjamin Neff <benjamin@coding4coffee.ch>
Date: Thu, 12 Oct 2017 02:43:37 +0200
Subject: [PATCH] Destroy user and person associations in batches

---
 lib/account_deleter.rb           | 21 ++++++++++++---------
 spec/lib/account_deleter_spec.rb | 18 +++++++++++++-----
 2 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/lib/account_deleter.rb b/lib/account_deleter.rb
index b14582980..356c5a54c 100644
--- a/lib/account_deleter.rb
+++ b/lib/account_deleter.rb
@@ -5,7 +5,6 @@
 #   the COPYRIGHT file.
 
 class AccountDeleter
-
   # Things that are not removed from the database:
   # - Comments
   # - Likes
@@ -44,7 +43,7 @@ class AccountDeleter
     tombstone_user
   end
 
-  #user deletions
+  # user deletions
   def normal_ar_user_associates_to_delete
     %i[tag_followings services aspects user_preferences
        notifications blocks authorizations o_auth_applications pairwise_pseudonymous_identifiers]
@@ -61,13 +60,17 @@ class AccountDeleter
 
   def delete_standard_user_associations
     normal_ar_user_associates_to_delete.each do |asso|
-      self.user.send(asso).each{|model| model.destroy }
+      user.send(asso).ids.each_slice(20) do |ids|
+        User.reflect_on_association(asso).class_name.constantize.where(id: ids).destroy_all
+      end
     end
   end
 
   def delete_standard_person_associations
     normal_ar_person_associates_to_delete.each do |asso|
-      self.person.send(asso).destroy_all
+      person.send(asso).ids.each_slice(20) do |ids|
+        Person.reflect_on_association(asso).class_name.constantize.where(id: ids).destroy_all
+      end
     end
   end
 
@@ -78,7 +81,7 @@ class AccountDeleter
   # Currently this would get deleted due to the db foreign key constrainsts,
   # but we'll keep this method here for completeness
   def remove_share_visibilities_on_contacts_posts
-    ShareVisibility.for_a_user(user).destroy_all
+    ShareVisibility.for_a_user(user).find_each(batch_size: 20, &:destroy)
   end
 
   def remove_conversation_visibilities
@@ -86,16 +89,16 @@ class AccountDeleter
   end
 
   def tombstone_person_and_profile
-    self.person.lock_access!
-    self.person.clear_profile!
+    person.lock_access!
+    person.clear_profile!
   end
 
   def tombstone_user
-    self.user.clear_account!
+    user.clear_account!
   end
 
   def delete_contacts_of_me
-    Contact.all_contacts_of_person(self.person).destroy_all
+    Contact.all_contacts_of_person(person).find_each(batch_size: 20, &:destroy)
   end
 
   def normal_ar_person_associates_to_delete
diff --git a/spec/lib/account_deleter_spec.rb b/spec/lib/account_deleter_spec.rb
index a82bbe578..a6445a3b9 100644
--- a/spec/lib/account_deleter_spec.rb
+++ b/spec/lib/account_deleter_spec.rb
@@ -96,8 +96,12 @@ describe AccountDeleter do
     it 'removes all standard user associaltions' do
       @account_deletion.normal_ar_user_associates_to_delete.each do |asso|
         association_double = double
-        expect(association_double).to receive(:destroy)
-        expect(bob).to receive(asso).and_return([association_double])
+        expect(association_double).to receive(:ids).and_return([42])
+        expect(bob).to receive(asso).and_return(association_double)
+        batch_double = double
+        expect(User.reflect_on_association(asso).class_name.constantize).to receive(:where)
+          .with(id: [42]).and_return(batch_double)
+        expect(batch_double).to receive(:destroy_all)
       end
 
       @account_deletion.delete_standard_user_associations
@@ -111,8 +115,12 @@ describe AccountDeleter do
     it 'removes all standard person associaltions' do
       @account_deletion.normal_ar_person_associates_to_delete.each do |asso|
         association_double = double
-        expect(association_double).to receive(:destroy_all)
+        expect(association_double).to receive(:ids).and_return([42])
         expect(bob.person).to receive(asso).and_return(association_double)
+        batch_double = double
+        expect(Person.reflect_on_association(asso).class_name.constantize).to receive(:where)
+          .with(id: [42]).and_return(batch_double)
+        expect(batch_double).to receive(:destroy_all)
       end
 
       @account_deletion.delete_standard_person_associations
@@ -133,7 +141,7 @@ describe AccountDeleter do
       it 'deletes all the local contact objects where deleted account is the person' do
         contacts = double
         expect(Contact).to receive(:all_contacts_of_person).with(bob.person).and_return(contacts)
-        expect(contacts).to receive(:destroy_all)
+        expect(contacts).to receive(:find_each).with(batch_size: 20)
         @account_deletion.delete_contacts_of_me
       end
     end
@@ -163,7 +171,7 @@ describe AccountDeleter do
     it "removes the share visibilities for a user" do
       s_vis = double
       expect(ShareVisibility).to receive(:for_a_user).with(bob).and_return(s_vis)
-      expect(s_vis).to receive(:destroy_all)
+      expect(s_vis).to receive(:find_each).with(batch_size: 20)
 
       @account_deletion.remove_share_visibilities_on_contacts_posts
     end