From 5f8851cb44a0bef3ace27b229409667bdc01707b Mon Sep 17 00:00:00 2001
From: Sam <sam.saffron@gmail.com>
Date: Wed, 2 Oct 2013 12:17:27 +1000
Subject: [PATCH] Avoid superfluous transaction when saving drafts

---
 app/models/draft.rb                       |  6 ++----
 lib/freedom_patches/active_record_base.rb | 14 ++++++++++++++
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/app/models/draft.rb b/app/models/draft.rb
index 012fb1c35bc..0972eb25e21 100644
--- a/app/models/draft.rb
+++ b/app/models/draft.rb
@@ -7,12 +7,10 @@ class Draft < ActiveRecord::Base
     d = find_draft(user,key)
     if d
       return if d.sequence > sequence
-      d.data = data
-      d.sequence = sequence
+      d.update_columns(data: data, sequence: sequence)
     else
-      d = Draft.new(user_id: user.id, draft_key: key, data: data, sequence: sequence)
+      Draft.create!(user_id: user.id, draft_key: key, data: data, sequence: sequence)
     end
-    d.save!
   end
 
   def self.get(user, key, sequence)
diff --git a/lib/freedom_patches/active_record_base.rb b/lib/freedom_patches/active_record_base.rb
index 21c97119783..96b2a1b232e 100644
--- a/lib/freedom_patches/active_record_base.rb
+++ b/lib/freedom_patches/active_record_base.rb
@@ -11,6 +11,20 @@ class ActiveRecord::Base
     exec_sql(*args).cmd_tuples
   end
 
+  # note: update_attributes still spins up a transaction this can cause contention
+  # this method performs the raw update sidestepping AR
+  def update_columns(hash)
+    sql = "UPDATE #{ self.class.table_name } SET "
+
+    sql << hash.map do |k,v|
+      "#{k} = :#{k}"
+    end.join(",")
+
+    sql << " WHERE id = :id"
+
+    exec_sql(sql, hash.merge(id: self.id))
+  end
+
   def exec_sql(*args)
     ActiveRecord::Base.exec_sql(*args)
   end