fixed tests, implemented sql based partitioning for favorites

db/migrate/20100211181944_create_favorites.rb

@@ -9,14 +9,44 @@ class CreateFavorites < ActiveRecord::Migration
     end
 
     0.upto(TABLE_COUNT - 1) do |i|
-      create_table "favorites_#{i}" do |t|
-        t.column :user_id, :integer
-        t.column :post_id, :integer
-      end
+      execute <<-EOS
+        create table favorites_#{i} (
+          check (user_id % 100 = #{i})
+        ) inherits (favorites)
+      EOS
       
       add_index "favorites_#{i}", :user_id
       add_index "favorites_#{i}", :post_id
     end
+    
+    fragment = []
+    
+    1.upto(TABLE_COUNT - 1) do |i|
+      fragment << <<-EOS
+        elsif (NEW.user_id % 100 = #{i}) then
+          insert into favorites_#{i} values (NEW.*);
+      EOS
+    end
+    
+    execute <<-EOS
+      create or replace function favorites_insert_trigger()
+      returns trigger as $$
+      begin
+        if (NEW.user_id % 100 = 0) then
+          insert into favorites_0 values (NEW.*);
+        #{fragment.join("\n")}
+        end if;
+        return NULL;
+      end;
+      $$
+      language plpgsql
+    EOS
+    
+    execute <<-EOS
+      create trigger insert_favorites_trigger
+      before insert on favorites
+      for each row execute procedure favorites_insert_trigger()
+    EOS
   end
 
   def self.down