diff --git a/doctrine-mapping.xsd b/doctrine-mapping.xsd
index 19aacd237..6216d75dc 100644
--- a/doctrine-mapping.xsd
+++ b/doctrine-mapping.xsd
@@ -88,6 +88,7 @@
     <xs:attribute name="repository-class" type="xs:string"/>
     <xs:attribute name="inheritance-type" type="orm:inheritance-type"/>
     <xs:attribute name="change-tracking-policy" type="orm:change-tracking-policy" />
+    <xs:attribute name="read-only" type="xs:boolean" default="false" />
   </xs:complexType>
   
   <xs:complexType name="mapped-superclass" >
diff --git a/lib/Doctrine/ORM/Mapping/ClassMetadata.php b/lib/Doctrine/ORM/Mapping/ClassMetadata.php
index 2465f1c3a..4ec0ede53 100644
--- a/lib/Doctrine/ORM/Mapping/ClassMetadata.php
+++ b/lib/Doctrine/ORM/Mapping/ClassMetadata.php
@@ -334,6 +334,10 @@ class ClassMetadata extends ClassMetadataInfo
             $serialized[] = 'namedQueries';
         }
 
+        if ($this->isReadOnly) {
+            $serialized[] = 'isReadOnly';
+        }
+
         return $serialized;
     }
 
diff --git a/lib/Doctrine/ORM/Mapping/ClassMetadataInfo.php b/lib/Doctrine/ORM/Mapping/ClassMetadataInfo.php
index 7db39621d..a10d8c866 100644
--- a/lib/Doctrine/ORM/Mapping/ClassMetadataInfo.php
+++ b/lib/Doctrine/ORM/Mapping/ClassMetadataInfo.php
@@ -484,6 +484,17 @@ class ClassMetadataInfo implements ClassMetadata
      */
     public $reflClass;
 
+    /**
+     * Is this entity marked as "read-only"?
+     *
+     * That means it is never considered for change-tracking in the UnitOfWork. It is a very helpful performance
+     * optimization for entities that are immutable, either in your domain or through the relation database
+     * (coming from a view, or a history table for example).
+     *
+     * @var bool
+     */
+    public $isReadOnly = false;
+
     /**
      * Initializes a new ClassMetadata instance that will hold the object-relational mapping
      * metadata of the class with the given name.
@@ -1818,4 +1829,14 @@ class ClassMetadataInfo implements ClassMetadata
     {
         $this->versionField = $versionField;
     }
+
+    /**
+     * Mark this class as read only, no change tracking is applied to it.
+     *
+     * @return void
+     */
+    public function markReadOnly()
+    {
+        $this->isReadOnly = true;
+    }
 }
diff --git a/lib/Doctrine/ORM/Mapping/Driver/AnnotationDriver.php b/lib/Doctrine/ORM/Mapping/Driver/AnnotationDriver.php
index f976d0aec..b74fc860e 100644
--- a/lib/Doctrine/ORM/Mapping/Driver/AnnotationDriver.php
+++ b/lib/Doctrine/ORM/Mapping/Driver/AnnotationDriver.php
@@ -132,6 +132,10 @@ class AnnotationDriver implements Driver
         if (isset($classAnnotations['Doctrine\ORM\Mapping\Entity'])) {
             $entityAnnot = $classAnnotations['Doctrine\ORM\Mapping\Entity'];
             $metadata->setCustomRepositoryClass($entityAnnot->repositoryClass);
+
+            if ($entityAnnot->readOnly) {
+                $metadata->markReadOnly();
+            }
         } else if (isset($classAnnotations['Doctrine\ORM\Mapping\MappedSuperclass'])) {
             $metadata->isMappedSuperclass = true;
         } else {
diff --git a/lib/Doctrine/ORM/Mapping/Driver/DoctrineAnnotations.php b/lib/Doctrine/ORM/Mapping/Driver/DoctrineAnnotations.php
index 31e712d42..84d2cd1c8 100644
--- a/lib/Doctrine/ORM/Mapping/Driver/DoctrineAnnotations.php
+++ b/lib/Doctrine/ORM/Mapping/Driver/DoctrineAnnotations.php
@@ -1,7 +1,5 @@
 <?php
 /*
- *  $Id$
- *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
@@ -27,6 +25,7 @@ use Doctrine\Common\Annotations\Annotation;
 
 final class Entity extends Annotation {
     public $repositoryClass;
+    public $readOnly = false;
 }
 final class MappedSuperclass extends Annotation {}
 final class InheritanceType extends Annotation {}
diff --git a/lib/Doctrine/ORM/Mapping/Driver/XmlDriver.php b/lib/Doctrine/ORM/Mapping/Driver/XmlDriver.php
index e42d89493..a42d449e6 100644
--- a/lib/Doctrine/ORM/Mapping/Driver/XmlDriver.php
+++ b/lib/Doctrine/ORM/Mapping/Driver/XmlDriver.php
@@ -55,6 +55,9 @@ class XmlDriver extends AbstractFileDriver
             $metadata->setCustomRepositoryClass(
                 isset($xmlRoot['repository-class']) ? (string)$xmlRoot['repository-class'] : null
             );
+            if (isset($xmlRoot['read-only']) && $xmlRoot['read-only'] == "true") {
+                $metadata->markReadOnly();
+            }
         } else if ($xmlRoot->getName() == 'mapped-superclass') {
             $metadata->isMappedSuperclass = true;
         } else {
diff --git a/lib/Doctrine/ORM/Mapping/Driver/YamlDriver.php b/lib/Doctrine/ORM/Mapping/Driver/YamlDriver.php
index 75bfeec74..97617a64d 100644
--- a/lib/Doctrine/ORM/Mapping/Driver/YamlDriver.php
+++ b/lib/Doctrine/ORM/Mapping/Driver/YamlDriver.php
@@ -49,6 +49,9 @@ class YamlDriver extends AbstractFileDriver
             $metadata->setCustomRepositoryClass(
                 isset($element['repositoryClass']) ? $element['repositoryClass'] : null
             );
+            if (isset($element['readOnly']) && $element['readOnly'] == true) {
+                $metadata->markReadOnly();
+            }
         } else if ($element['type'] == 'mappedSuperclass') {
             $metadata->isMappedSuperclass = true;
         } else {
diff --git a/lib/Doctrine/ORM/UnitOfWork.php b/lib/Doctrine/ORM/UnitOfWork.php
index 79c946f87..945815a69 100644
--- a/lib/Doctrine/ORM/UnitOfWork.php
+++ b/lib/Doctrine/ORM/UnitOfWork.php
@@ -514,9 +514,9 @@ class UnitOfWork implements PropertyChangedListener
             $class = $this->em->getClassMetadata($className);
 
             // Skip class if instances are read-only
-            //if ($class->isReadOnly) {
-            //    continue;
-            //}
+            if ($class->isReadOnly) {
+                continue;
+            }
 
             // If change tracking is explicit or happens through notification, then only compute
             // changes on entities of that type that are explicitly marked for synchronization.
diff --git a/tests/Doctrine/Tests/ORM/Functional/AllTests.php b/tests/Doctrine/Tests/ORM/Functional/AllTests.php
index cac410281..4dd2b0644 100644
--- a/tests/Doctrine/Tests/ORM/Functional/AllTests.php
+++ b/tests/Doctrine/Tests/ORM/Functional/AllTests.php
@@ -59,6 +59,7 @@ class AllTests
         $suite->addTestSuite('Doctrine\Tests\ORM\Functional\PostgreSQLIdentityStrategyTest');
         $suite->addTestSuite('Doctrine\Tests\ORM\Functional\ExtraLazyCollectionTest');
         $suite->addTestSuite('Doctrine\Tests\ORM\Functional\ClearEventTest');
+        $suite->addTestSuite('Doctrine\Tests\ORM\Functional\ReadOnlyTest');
         
         $suite->addTest(Locking\AllTests::suite());
         $suite->addTest(Ticket\AllTests::suite());
diff --git a/tests/Doctrine/Tests/ORM/Functional/ReadOnlyTest.php b/tests/Doctrine/Tests/ORM/Functional/ReadOnlyTest.php
new file mode 100644
index 000000000..8a5819956
--- /dev/null
+++ b/tests/Doctrine/Tests/ORM/Functional/ReadOnlyTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Doctrine\Tests\ORM\Functional;
+
+require_once __DIR__ . '/../../TestInit.php';
+
+/**
+ * Functional Query tests.
+ *
+ * @group DDC-692
+ */
+class ReadOnlyTest extends \Doctrine\Tests\OrmFunctionalTestCase
+{
+    protected function setUp()
+    {
+        parent::setUp();
+
+        $this->_schemaTool->createSchema(array(
+            $this->_em->getClassMetadata('Doctrine\Tests\ORM\Functional\ReadOnlyEntity'),
+        ));
+    }
+
+    public function testReadOnlyEntityNeverChangeTracked()
+    {
+        $readOnly = new ReadOnlyEntity("Test1", 1234);
+        $this->_em->persist($readOnly);
+        $this->_em->flush();
+
+        $readOnly->name = "Test2";
+        $readOnly->number = 4321;
+
+        $this->_em->flush();
+        $this->_em->clear();
+
+        $dbReadOnly = $this->_em->find('Doctrine\Tests\ORM\Functional\ReadOnlyEntity', $readOnly->id);
+        $this->assertEquals("Test1", $dbReadOnly->name);
+        $this->assertEquals(1234, $dbReadOnly->number);
+    }
+}
+
+/**
+ * @Entity(readOnly=true)
+ */
+class ReadOnlyEntity
+{
+    /**
+     * @Id @GeneratedValue @Column(type="integer")
+     * @var int
+     */
+    public $id;
+    /** @column(type="string") */
+    public $name;
+    /** @Column(type="integer") */
+    public $number;
+
+    public function __construct($name, $number)
+    {
+        $this->name = $name;
+        $this->number = $number;
+    }
+}
\ No newline at end of file
diff --git a/tests/Doctrine/Tests/ORM/Mapping/ClassMetadataTest.php b/tests/Doctrine/Tests/ORM/Mapping/ClassMetadataTest.php
index 9f3bc357e..8f57280df 100644
--- a/tests/Doctrine/Tests/ORM/Mapping/ClassMetadataTest.php
+++ b/tests/Doctrine/Tests/ORM/Mapping/ClassMetadataTest.php
@@ -30,6 +30,8 @@ class ClassMetadataTest extends \Doctrine\Tests\OrmTestCase
         $cm->setCustomRepositoryClass("UserRepository");
         $cm->setDiscriminatorColumn(array('name' => 'disc', 'type' => 'integer'));
         $cm->mapOneToOne(array('fieldName' => 'phonenumbers', 'targetEntity' => 'Bar', 'mappedBy' => 'foo'));
+        $cm->markReadOnly();
+        $cm->addNamedQuery(array('name' => 'dql', 'query' => 'foo'));
         $this->assertEquals(1, count($cm->associationMappings));
 
         $serialized = serialize($cm);
@@ -51,6 +53,8 @@ class ClassMetadataTest extends \Doctrine\Tests\OrmTestCase
         $this->assertTrue($oneOneMapping['fetch'] == ClassMetadata::FETCH_LAZY);
         $this->assertEquals('phonenumbers', $oneOneMapping['fieldName']);
         $this->assertEquals('Doctrine\Tests\Models\CMS\Bar', $oneOneMapping['targetEntity']);
+        $this->assertTrue($cm->isReadOnly);
+        $this->assertEquals(array('dql' => 'foo'), $cm->namedQueries);
     }
 
     public function testFieldIsNullable()