query the slave for some expensive queries

Change-Id: Ic2716b75551a85fc028fa7ac0673bf5cb01f14d1
Reviewed-on: https://gerrit.instructure.com/13042
Reviewed-by: Zach Wily <zach@instructure.com>
Tested-by: Brian Palmer <brianp@instructure.com>

Author: codekitchen

app/models/attachment.rb

@@ -572,9 +572,11 @@ def self.get_quota(context)
     quota = 0
     quota_used = 0
     if context
-      quota = Setting.get_cached('context_default_quota', 50.megabytes.to_s).to_i
-      quota = context.quota if (context.respond_to?("quota") && context.quota)
-      quota_used = context.attachments.active.sum('COALESCE(size, 0)', :conditions => { :root_attachment_id => nil }).to_i
+      ActiveRecord::Base::ConnectionSpecification.with_environment(:slave) do
+        quota = Setting.get_cached('context_default_quota', 50.megabytes.to_s).to_i
+        quota = context.quota if (context.respond_to?("quota") && context.quota)
+        quota_used = context.attachments.active.sum('COALESCE(size, 0)', :conditions => { :root_attachment_id => nil }).to_i
+      end
     end
     {:quota => quota, :quota_used => quota_used}
   end

lib/summary_message_consolidator.rb

@@ -26,7 +26,9 @@ def initialize(n=nil)
   end
 
   def process
-    cc_ids = CommunicationChannel.ids_with_pending_delayed_messages
+    cc_ids = ActiveRecord::Base::ConnectionSpecification.with_environment(:slave) do
+      CommunicationChannel.ids_with_pending_delayed_messages
+    end
     cc_ids.each do |cc_id|
       dm_ids = DelayedMessage.ids_for_messages_with_communication_channel_id(cc_id)
       DelayedMessage.update_all({ :batched_at => Time.now.utc, :workflow_state => 'sent', :updated_at => Time.now.utc },