Improved performance in menu rendering when there are very many pages…

… by first querying the translations table and then using those results in the pages table rather than the other way around. There are still too many queries in the logfile for my liking so this has a way to come.

core/app/views/shared/_menu.html.erb

@@ -11,15 +11,14 @@
       selected_item = collection.detect{|page| selected_page?(page)}
       selected_item = @page if selected_item.nil?
     end
-    sibling_count = roots.length - 1
 -%>
     <nav id='<%= dom_id %>' class='<%= %W(#{css} clearfix).join(' ') %>'>
       <ul>
         <%= render :partial => "/shared/menu_branch",
                    :collection => roots,
                    :locals => {
                      :hide_children => hide_children,
-                     :sibling_count => sibling_count,
+                     :sibling_count => (roots.length - 1),
                      :collection => collection,
                      :selected_item => selected_item,
                      :apply_css => true #if you don't care about class='first' class='last' or class='selected' set apply_css to false for speed.

core/app/views/shared/_menu_branch.html.erb

@@ -5,7 +5,11 @@
   dom_id = ("id='item_#{menu_branch_counter}'" if menu_branch.parent_id.nil? and menu_branch.title.present?)
 
   hide_children = (defined?(hide_children) && hide_children)
-  children = (hide_children || !menu_branch.has_descendants?) ? [] : collection.select { |p| p.parent_id == menu_branch.id }
+  children = if (hide_children || !menu_branch.has_descendants?)
+    []
+  else
+    collection.select { |p| p.parent_id == menu_branch.id }
+  end
 -%>
 <li<%= ['', css, dom_id].compact.join(' ').gsub(/\ *$/, '') %>>
   <%= link_to menu_branch.title, menu_branch.url -%>

core/lib/refinery/application_controller.rb

@@ -87,7 +87,7 @@ def login?
 
       # get all the pages to be displayed in the site menu.
       def find_pages_for_menu
-        @menu_pages = Page.live.in_menu.order('lft ASC')
+        @menu_pages = Page.in_menu.live.order('lft ASC')
       end
 
       # use a different model for the meta information.

pages/app/models/page.rb

@@ -32,14 +32,14 @@ class Page < ActiveRecord::Base
 
   scope :live, where(:draft => false)
 
-  # shows all pages with :show_in_menu set to true, but it also
+  # Shows all pages with :show_in_menu set to true, but it also
   # rejects any page that has not been translated to the current locale.
+  # This works using a query against the translated content first and then
+  # using all of the page_ids we further filter against this model's table.
   scope :in_menu, lambda {
-    pages = Arel::Table.new(Page.table_name)
-    translations = Arel::Table.new(Page.translations_table_name)
-
-    includes(:translations).where(:show_in_menu => true).where(
-      translations[:locale].eq(Globalize.locale)).where(pages[:id].eq(translations[:page_id]))
+    includes(:translations).where(Page.arel_table[:id].in(
+      Page::Translation.where(:locale => Globalize.locale).map(&:page_id)
+    )).where(:show_in_menu => true)
   }
 
   # when a dialog pops up to link to a page, how many pages per page should there be