Little things:

- Retries on deadlock when calculating average time
- Removes Warning: When specifying html format for errors
- Doesn't use manual SQL to update user's ip address

app/controllers/application_controller.rb

@@ -66,12 +66,12 @@ class ApplicationController < ActionController::Base
       # for now do a simple remap, we may look at cleaner ways of doing the render
       raise ActiveRecord::RecordNotFound
     else
-      render file: 'public/404.html', layout: false, status: 404
+      render file: 'public/404', formats: [:html], layout: false, status: 404
     end
   end
 
   rescue_from Discourse::InvalidAccess do
-    render file: 'public/403.html', layout: false, status: 403
+    render file: 'public/403', formats: [:html], layout: false, status: 403
   end
 
   def store_preloaded(key, json)

app/models/post.rb

@@ -342,19 +342,21 @@ class Post < ActiveRecord::Base
   # This calculates the geometric mean of the post timings and stores it along with
   # each post.
   def self.calculate_avg_time
-    exec_sql("UPDATE posts
-              SET avg_time = (x.gmean / 1000)
-              FROM (SELECT post_timings.topic_id,
-                           post_timings.post_number,
-                           round(exp(avg(ln(msecs)))) AS gmean
-                    FROM post_timings
-                    INNER JOIN posts AS p2
-                      ON p2.post_number = post_timings.post_number
-                        AND p2.topic_id = post_timings.topic_id
-                        AND p2.user_id <> post_timings.user_id
-                    GROUP BY post_timings.topic_id, post_timings.post_number) AS x
-              WHERE x.topic_id = posts.topic_id
-                AND x.post_number = posts.post_number")
+    retry_lock_error do
+      exec_sql("UPDATE posts
+                SET avg_time = (x.gmean / 1000)
+                FROM (SELECT post_timings.topic_id,
+                             post_timings.post_number,
+                             round(exp(avg(ln(msecs)))) AS gmean
+                      FROM post_timings
+                      INNER JOIN posts AS p2
+                        ON p2.post_number = post_timings.post_number
+                          AND p2.topic_id = post_timings.topic_id
+                          AND p2.user_id <> post_timings.user_id
+                      GROUP BY post_timings.topic_id, post_timings.post_number) AS x
+                WHERE x.topic_id = posts.topic_id
+                  AND x.post_number = posts.post_number")
+    end
   end
 
   before_save do

lib/current_user.rb

@@ -23,7 +23,7 @@ module CurrentUser
       @current_user.update_last_seen! 
       if @current_user.ip_address != request.remote_ip
         @current_user.ip_address = request.remote_ip
-        User.exec_sql('update users set ip_address = ? where id = ?', request.remote_ip, @current_user.id)
+        @current_user.update_column(:ip_address, request.remote_ip)
       end
     end
     @current_user

lib/freedom_patches/active_record_base.rb

@@ -15,6 +15,24 @@ class ActiveRecord::Base
     ActiveRecord::Base.exec_sql(*args)
   end
 
+
+  # Executes the given block +retries+ times (or forever, if explicitly given nil),
+  # catching and retrying SQL Deadlock errors.
+  #
+  # Thanks to: http://stackoverflow.com/a/7427186/165668
+  #
+  def self.retry_lock_error(retries=5, &block)
+    begin
+      yield
+    rescue ActiveRecord::StatementInvalid => e
+      if e.message =~ /Deadlock found when trying to get lock/ and (retries.nil? || retries > 0)
+        retry_lock_error(retries ? retries - 1 : nil, &block)
+      else
+        raise e
+      end
+    end
+  end
+
   # Support for psql. If we want to support multiple RDBMs in the future we can
   # split this.
   def exec_sql_row_count(*args)