Significant (98.87%) improvement in the speed up Vehicles#Current dat…

…abase queries. 1046ms -> 1ms

db/migrate/20101204232129_add_vehicle_timestamp_index_to_updates.rb

@@ -0,0 +1,9 @@
+class AddVehicleTimestampIndexToUpdates < ActiveRecord::Migration
+  def self.up
+    add_index :updates, [:vehicle_id, :timestamp]
+  end
+
+  def self.down
+    remove_index :updates, [:vehicle_id, :timestamp]
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20101108204713) do
+ActiveRecord::Schema.define(:version => 20101204232129) do
 
   create_table "coords", :force => true do |t|
     t.decimal  "latitude",   :precision => 15, :scale => 10, :default => 0.0
@@ -81,6 +81,8 @@
     t.datetime "updated_at"
   end
 
+  add_index "updates", ["vehicle_id", "timestamp"], :name => "index_updates_on_vehicle_id_and_timestamp"
+
   create_table "users", :force => true do |t|
     t.string   "username"
     t.integer  "sign_in_count",      :default => 0