add a session authorization setter to the pg connection

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -389,6 +389,11 @@ module ActiveRecord
         end
       end
 
+      # Set the authorized user for this session
+      def session_auth=(user)
+        exec "SET SESSION AUTHORIZATION #{user}"
+      end
+
       # REFERENTIAL INTEGRITY ====================================
 
       def supports_disable_referential_integrity?() #:nodoc:

activerecord/test/cases/adapters/postgresql/schema_authorization_test.rb

@@ -43,6 +43,13 @@ class SchemaAuthorizationTest < ActiveRecord::TestCase
     end
   end
 
+  def test_session_auth=
+    assert_raise(ActiveRecord::StatementInvalid) do
+      @connection.session_auth = 'DEFAULT'
+      @connection.execute "SELECT * FROM #{TABLE_NAME}"
+    end
+  end
+
   def test_auth_with_bind
     assert_nothing_raised do
       set_session_auth
@@ -90,7 +97,7 @@ class SchemaAuthorizationTest < ActiveRecord::TestCase
 
   private
     def set_session_auth auth = nil
-       @connection.execute "SET SESSION AUTHORIZATION #{auth || 'default'}"
+       @connection.session_auth =  auth || 'default'
     end
 
 end