diff --git a/lib/generators/active_record/templates/create_impressions_table.rb b/lib/generators/active_record/templates/create_impressions_table.rb
index e3fa7d5..5282380 100644
--- a/lib/generators/active_record/templates/create_impressions_table.rb
+++ b/lib/generators/active_record/templates/create_impressions_table.rb
@@ -14,6 +14,7 @@ class CreateImpressionsTable < ActiveRecord::Migration
       t.text :referrer
       t.timestamps
     end
+    add_index :impressions, [:impressionable_type, :message, :impressionable_id], :name => "impressionable_type_message_index", :unique => false
     add_index :impressions, [:impressionable_type, :impressionable_id, :request_hash], :name => "poly_request_index", :unique => false
     add_index :impressions, [:impressionable_type, :impressionable_id, :ip_address], :name => "poly_ip_index", :unique => false
     add_index :impressions, [:impressionable_type, :impressionable_id, :session_hash], :name => "poly_session_index", :unique => false
diff --git a/upgrade_migrations/version_1_1_2.rb b/upgrade_migrations/version_1_1_2.rb
new file mode 100644
index 0000000..1157327
--- /dev/null
+++ b/upgrade_migrations/version_1_1_2.rb
@@ -0,0 +1,9 @@
+class Version04UpdateImpressionsTable < ActiveRecord::Migration
+  def self.up
+    add_index :impressions, [:impressionable_type, :message, :impressionable_id], :name => "impressionable_type_message_index", :unique => false
+  end
+
+  def self.down
+    remove_column :impressions, :impressionable_type_message_index
+  end
+end