diff --git a/core/lib/Drupal/Core/Config/CachedStorage.php b/core/lib/Drupal/Core/Config/CachedStorage.php
index c27d2c6..a5d11fd 100644
--- a/core/lib/Drupal/Core/Config/CachedStorage.php
+++ b/core/lib/Drupal/Core/Config/CachedStorage.php
@@ -41,13 +41,6 @@ class CachedStorage implements StorageInterface, StorageCacheInterface {
   protected $findByPrefixCache = array();
 
   /**
-   * The cache prefix to use for all cache entries.
-   *
-   * @var string
-   */
-  protected $cachePrefix = NULL;
-
-  /**
    * Constructs a new CachedStorage.
    *
    * @param \Drupal\Core\Config\StorageInterface $storage
@@ -74,7 +67,7 @@ public function exists($name) {
    * Implements Drupal\Core\Config\StorageInterface::read().
    */
   public function read($name) {
-    if ($cache = $this->cache->get($this->getCacheKey($name))) {
+    if ($cache = $this->cache->get($name)) {
       // The cache contains either the cached configuration data or FALSE
       // if the configuration file does not exist.
       return $cache->data;
@@ -82,7 +75,7 @@ public function read($name) {
     // Read from the storage on a cache miss and cache the data. Also cache
     // information about missing configuration objects.
     $data = $this->storage->read($name);
-    $this->cache->set($this->getCacheKey($name), $data);
+    $this->cache->set($name, $data);
     return $data;
   }
 
@@ -94,24 +87,23 @@ public function readMultiple(array $names) {
     // The names array is passed by reference and will only contain the names of
     // config object not found after the method call.
     // @see \Drupal\Core\Cache\CacheBackendInterface::getMultiple()
-    $cids = $this->getCacheKeys($names);
-    $cached_list = $this->cache->getMultiple($cids);
+    $cached_list = $this->cache->getMultiple($names);
 
-    if (!empty($cids)) {
-      $list = $this->storage->readMultiple(array_keys($cids));
+    if (!empty($names)) {
+      $list = $this->storage->readMultiple($names);
       // Cache configuration objects that were loaded from the storage, cache
       // missing configuration objects as an explicit FALSE.
       $items = array();
       foreach ($names as $name) {
-        $items[$this->getCacheKey($name)] = array('data' => isset($list[$name]) ? $list[$name] : FALSE);
+        $items[$name] = array('data' => isset($list[$name]) ? $list[$name] : FALSE);
       }
 
       $this->cache->setMultiple($items);
     }
 
     // Add the configuration objects from the cache to the list.
-    foreach ($cached_list as $cid => $cache) {
-      $list[$this->getNameFromCacheKey($cid)] = $cache->data;
+    foreach ($cached_list as $name => $cache) {
+      $list[$name] = $cache->data;
     }
 
     // Ensure that only existing configuration objects are returned, filter out
@@ -126,8 +118,7 @@ public function write($name, array $data) {
     if ($this->storage->write($name, $data)) {
       // While not all written data is read back, setting the cache instead of
       // just deleting it avoids cache rebuild stampedes.
-      $this->cache->set($this->getCacheKey($name), $data);
-      // @todo: How to deal with the prefix for the tag?
+      $this->cache->set($name, $data);
       Cache::deleteTags(array($this::FIND_BY_PREFIX_CACHE_TAG => TRUE));
       $this->findByPrefixCache = array();
       return TRUE;
@@ -142,7 +133,7 @@ public function delete($name) {
     // If the cache was the first to be deleted, another process might start
     // rebuilding the cache before the storage is gone.
     if ($this->storage->delete($name)) {
-      $this->cache->delete($this->getCacheKey($name));
+      $this->cache->delete($name);
       Cache::deleteTags(array($this::FIND_BY_PREFIX_CACHE_TAG => TRUE));
       $this->findByPrefixCache = array();
       return TRUE;
@@ -157,8 +148,8 @@ public function rename($name, $new_name) {
     // If the cache was the first to be deleted, another process might start
     // rebuilding the cache before the storage is renamed.
     if ($this->storage->rename($name, $new_name)) {
-      $this->cache->delete($this->getCacheKey($name));
-      $this->cache->delete($this->getCacheKey($new_name));
+      $this->cache->delete($name);
+      $this->cache->delete($new_name);
       Cache::deleteTags(array($this::FIND_BY_PREFIX_CACHE_TAG => TRUE));
       $this->findByPrefixCache = array();
       return TRUE;
@@ -211,13 +202,13 @@ protected function findByPrefix($prefix) {
     if (!isset($this->findByPrefixCache[$prefix])) {
       // The : character is not allowed in config file names, so this can not
       // conflict.
-      if ($cache = $this->cache->get($this->getCacheKey('find:' . $prefix))) {
+      if ($cache = $this->cache->get('find:' . $prefix)) {
         $this->findByPrefixCache[$prefix] = $cache->data;
       }
       else {
         $this->findByPrefixCache[$prefix] = $this->storage->listAll($prefix);
         $this->cache->set(
-          $this->getCacheKey('find:' . $prefix),
+          'find:' . $prefix,
           $this->findByPrefixCache[$prefix],
           Cache::PERMANENT,
           array($this::FIND_BY_PREFIX_CACHE_TAG => TRUE)
@@ -233,9 +224,9 @@ protected function findByPrefix($prefix) {
   public function deleteAll($prefix = '') {
     // If the cache was the first to be deleted, another process might start
     // rebuilding the cache before the storage is renamed.
-    $names = $this->storage->listAll($prefix);
+    $cids = $this->storage->listAll($prefix);
     if ($this->storage->deleteAll($prefix)) {
-      $this->cache->deleteMultiple($this->getCacheKeys($names));
+      $this->cache->deleteMultiple($cids);
       return TRUE;
     }
     return FALSE;
@@ -247,58 +238,4 @@ public function deleteAll($prefix = '') {
   public function resetListCache() {
     $this->findByPrefixCache = array();
   }
-
-  /**
-   * Builds the cache key for a config name.
-   *
-   * @param string $name
-   *   Name of the config file.
-   *
-   * @return string
-   *   The cache key.
-   */
-  protected function getCacheKey($name) {
-    return $this->cachePrefix ? $this->cachePrefix . ':' . $name : $name;
-  }
-
-  /**
-   * Builds the cache key for a list of config names.
-   *
-   * @param array $names
-   *   List of config file names.
-   *
-   * @return array
-   *   List of cache keys, keyed by config name.
-   */
-  protected function getCacheKeys(array $names) {
-    $cids = array();
-    foreach ($names as $name) {
-      $cids[$name] = $this->getCacheKey($name);
-    }
-    return $cids;
-  }
-
-  /**
-   * Returns the config name from a cache key.
-   *
-   * @param string $cid
-   *   Cache key
-   *
-   * @return string
-   *   Name of the config file.
-   */
-  protected function getNameFromCacheKey($cid) {
-    return $this->cachePrefix ? substr($cid, strlen($this->cachePrefix) + 1) : $cid;
-  }
-
-  /**
-   * Set the cache prefix used by this storage.
-   *
-   * @param string $cachePrefix
-   *   Name of the prefix that should be used for all cache IDs.
-   */
-  public function setCachePrefix($cachePrefix) {
-    $this->cachePrefix = $cachePrefix;
-  }
-
 }
diff --git a/core/lib/Drupal/Core/Config/DatabaseStorage.php b/core/lib/Drupal/Core/Config/DatabaseStorage.php
index 11ab691..c7d1cd2 100644
--- a/core/lib/Drupal/Core/Config/DatabaseStorage.php
+++ b/core/lib/Drupal/Core/Config/DatabaseStorage.php
@@ -73,18 +73,10 @@ public function exists($name) {
    * {@inheritdoc}
    */
   public function read($name) {
-    $data = FALSE;
-    try {
-      $raw = $this->connection->query('SELECT data FROM {' . $this->connection->escapeTable($this->table) . '} WHERE name = :name', array(':name' => $name), $this->options)->fetchField();
-      if ($raw !== FALSE) {
-        $data = $this->decode($raw);
-      }
+    $data = $this->readMultiple(array($name));
+    if (isset($data[$name])) {
+      return $data[$name];
     }
-    catch (\Exception $e) {
-      // If we attempt a read without actually having the database or the table
-      // available, just return FALSE so the caller can handle it.
-    }
-    return $data;
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Config/FileStorage.php b/core/lib/Drupal/Core/Config/FileStorage.php
index facba21..1dac0f4 100644
--- a/core/lib/Drupal/Core/Config/FileStorage.php
+++ b/core/lib/Drupal/Core/Config/FileStorage.php
@@ -215,14 +215,4 @@ public function deleteAll($prefix = '') {
 
     return $success;
   }
-
-  /**
-   * Sets the filesystem path for configuration objects.
-   *
-   * @param string $directory
-   *   The filesystem path for configuration objects.
-   */
-  public function setDirectory($directory) {
-    $this->directory = $directory;
-  }
 }
diff --git a/core/modules/language/language.install b/core/modules/language/language.install
index 8825db3..7f529d5 100644
--- a/core/modules/language/language.install
+++ b/core/modules/language/language.install
@@ -5,10 +5,18 @@
  * Install, update and uninstall functions for the language module.
  */
 
+use Drupal\language\Config\LanguageOverrideDatabaseStorage;
+
 /**
  * Implements hook_install().
  */
 function language_install() {
+  // Make sure that the config storage table is created.
+  $storage = \Drupal::service('language.config_storage');
+  if ($storage instanceof LanguageOverrideDatabaseStorage) {
+    $storage->ensureTableExists();
+  }
+
   // Get all the existing modules that are enabled and install any language
   // configuration.
   $language_config_override = \Drupal::service('language.config_factory_override');
diff --git a/core/modules/language/language.services.yml b/core/modules/language/language.services.yml
index 48c7c82..6aa5b2f 100644
--- a/core/modules/language/language.services.yml
+++ b/core/modules/language/language.services.yml
@@ -18,11 +18,9 @@ services:
     factory_method: get
     factory_service: cache_factory
     arguments: [language_config]
-  language.config_storage.file:
-    class: Drupal\language\Config\LanguageOverrideFileStorage
   language.config_storage:
-    class: Drupal\language\Config\LanguageOverrideCachedStorage
-    arguments: ['@language.config_storage.file', '@language.cache_config']
+      class: Drupal\language\Config\LanguageOverrideDatabaseStorage
+      arguments: ['@database', 'config_language']
   language.config_factory_override:
     class: Drupal\language\Config\LanguageConfigFactoryOverride
     arguments: ['@language.config_storage', '@event_dispatcher', '@config.typed']
diff --git a/core/modules/language/lib/Drupal/language/Config/LanguageConfigFactoryOverride.php b/core/modules/language/lib/Drupal/language/Config/LanguageConfigFactoryOverride.php
index 37bdf9e..ed769fd 100644
--- a/core/modules/language/lib/Drupal/language/Config/LanguageConfigFactoryOverride.php
+++ b/core/modules/language/lib/Drupal/language/Config/LanguageConfigFactoryOverride.php
@@ -133,7 +133,7 @@ public function setLanguageFromDefault(LanguageDefault $language_default = NULL)
    */
   public function install($type, $name) {
     // Work out if this extension provides default language overrides.
-    $config_dir = drupal_get_path($type, $name) . '/config/language';
+    $config_dir = drupal_get_path($type, $name) . '/config/install/language';
     if (is_dir($config_dir)) {
       // List all the directories.
       // \DirectoryIterator on Windows requires an absolute path.
@@ -158,22 +158,7 @@ public function install($type, $name) {
    * @todo maybe this should be done somewhere else?
    */
   public function uninstall($type, $name) {
-    // Can not use ConfigurableLanguageManager::getLanguages() since that would
-    // create a circular dependency.
-    $language_directory = config_get_config_directory() .'/language';
-    if (is_dir(($language_directory))) {
-      $it  = new \DirectoryIterator(realpath($language_directory));
-      foreach ($it as $dir) {
-        if (!$dir->isDot() && $dir->isDir() ) {
-          $this->storage->setLangcode($dir->getFilename());
-          $config_names = $this->storage->listAll($name . '.');
-          foreach ($config_names as $config_name) {
-            $config = new LanguageConfigOverride($config_name, $this->storage, $this->typedConfigManager);
-            $config->delete();
-          }
-        }
-      }
-    }
+    $this->storage->deleteAllLanguages($name . '.');
   }
 
 }
diff --git a/core/modules/language/lib/Drupal/language/Config/LanguageOverrideCachedStorage.php b/core/modules/language/lib/Drupal/language/Config/LanguageOverrideCachedStorage.php
deleted file mode 100644
index 4026102..0000000
--- a/core/modules/language/lib/Drupal/language/Config/LanguageOverrideCachedStorage.php
+++ /dev/null
@@ -1,55 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\language\Config\LanguageOverrideFileStorage.
- */
-
-namespace Drupal\language\Config;
-
-use Drupal\Core\Cache\CacheBackendInterface;
-use Drupal\Core\Config\CachedStorage;
-
-/**
- * Defines cached storage for language configuration overrides.
- */
-class LanguageOverrideCachedStorage extends CachedStorage implements LanguageOverrideStorageInterface {
-
-  /**
-   * The language configuration storage to be cached.
-   *
-   * @var \Drupal\language\Config\LanguageOverrideStorageInterface
-   */
-  protected $storage;
-
-  /**
-   * Constructs a new LanguageOverrideCachedStorage controller.
-   *
-   * @param \Drupal\language\Config\LanguageOverrideStorageInterface $storage
-   *   A configuration storage controller to be cached.
-   * @param \Drupal\Core\Cache\CacheBackendInterface $cache
-   *   A cache backend instance to use for caching.
-   */
-  public function __construct(LanguageOverrideStorageInterface $storage, CacheBackendInterface $cache) {
-    parent::__construct($storage, $cache);
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function setLangcode($langcode) {
-    $this->cachePrefix = $langcode;
-    $this->storage->setLangcode($langcode);
-    return $this;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  function __clone() {
-    // Also clone the inner storage, so that language code changes work as
-    // expected.
-    $this->storage = clone $this->storage;
-  }
-
-}
diff --git a/core/modules/language/lib/Drupal/language/Config/LanguageOverrideDatabaseStorage.php b/core/modules/language/lib/Drupal/language/Config/LanguageOverrideDatabaseStorage.php
new file mode 100644
index 0000000..ae8fcb6
--- /dev/null
+++ b/core/modules/language/lib/Drupal/language/Config/LanguageOverrideDatabaseStorage.php
@@ -0,0 +1,171 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\language\Config\LanguageOverrideDatabaseStorage.
+ */
+
+namespace Drupal\language\Config;
+
+use Drupal\Core\Config\DatabaseStorage;
+use Drupal\Core\Database\Database;
+
+/**
+ * Defines cached storage for language configuration overrides.
+ */
+class LanguageOverrideDatabaseStorage extends DatabaseStorage implements LanguageOverrideStorageInterface {
+
+  /**
+   * THe language code.
+   *
+   * @var string
+   */
+  protected $langcode;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function exists($name) {
+    try {
+      return (bool) $this->connection->queryRange('SELECT 1 FROM {' . $this->connection->escapeTable($this->table) . '} WHERE name = :name AND langcode = :langcode', 0, 1, array(
+        ':name' => $name,
+        ':langcode' => $this->langcode,
+      ), $this->options)->fetchField();
+    }
+    catch (\Exception $e) {
+      // If we attempt a read without actually having the database or the table
+      // available, just return FALSE so the caller can handle it.
+      return FALSE;
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function readMultiple(array $names) {
+    $list = array();
+    try {
+      $list = $this->connection->query('SELECT name, data FROM {' . $this->connection->escapeTable($this->table) . '} WHERE name IN (:names) AND langcode = :langcode', array(':names' => $names, ':langcode' => $this->langcode), $this->options)->fetchAllKeyed();
+      foreach ($list as &$data) {
+        $data = $this->decode($data);
+      }
+    }
+    catch (\Exception $e) {
+      // If we attempt a read without actually having the database or the table
+      // available, just return an empty array so the caller can handle it.
+    }
+    return $list;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function doWrite($name, $data) {
+    $options = array('return' => Database::RETURN_AFFECTED) + $this->options;
+    return (bool) $this->connection->merge($this->table, $options)
+      ->keys(array('name' => $name, 'langcode' => $this->langcode))
+      ->fields(array('data' => $data))
+      ->execute();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function ensureTableExists() {
+    return parent::ensureTableExists();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static function schemaDefinition() {
+    $schema = parent::schemaDefinition();
+    $schema['fields']['langcode'] = array(
+      'description' => 'The {language}.langcode of this configuration data.',
+      'type' => 'varchar',
+      'length' => 12,
+      'not null' => TRUE,
+    );
+    $schema['primary key'] = array('name', 'langcode');
+    return $schema;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function delete($name) {
+    $options = array('return' => Database::RETURN_AFFECTED) + $this->options;
+    return (bool) $this->connection->delete($this->table, $options)
+      ->condition('name', $name)
+      ->condition('langcode', $this->langcode)
+      ->execute();
+  }
+
+
+  /**
+   * {@inheritdoc}
+   */
+  public function rename($name, $new_name) {
+    $options = array('return' => Database::RETURN_AFFECTED) + $this->options;
+    return (bool) $this->connection->update($this->table, $options)
+      ->fields(array('name' => $new_name))
+      ->condition('name', $name)
+      ->execute();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function listAll($prefix = '') {
+    try {
+      return $this->connection->query('SELECT name FROM {' . $this->connection->escapeTable($this->table) . '} WHERE name LIKE :name AND langcode = :langcode', array(
+        ':name' => $this->connection->escapeLike($prefix) . '%',
+        ':langcode' => $this->langcode,
+      ), $this->options)->fetchCol();
+    }
+    catch (\Exception $e) {
+      return array();
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function deleteAll($prefix = '') {
+    try {
+      $options = array('return' => Database::RETURN_AFFECTED) + $this->options;
+      return (bool) $this->connection->delete($this->table, $options)
+        ->condition('name', $prefix . '%', 'LIKE')
+        ->condition('langcode', $this->langcode)
+        ->execute();
+    }
+    catch (\Exception $e) {
+      return FALSE;
+    }
+  }
+
+
+  /**
+   * {@inheritdoc}
+   */
+  public function deleteAllLanguages($prefix) {
+    try {
+      $options = array('return' => Database::RETURN_AFFECTED) + $this->options;
+      return (bool) $this->connection->delete($this->table, $options)
+        ->condition('name', $prefix . '%', 'LIKE')
+        ->execute();
+    }
+    catch (\Exception $e) {
+      return FALSE;
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setLangcode($langcode) {
+    $this->langcode = $langcode;
+    return $this;
+  }
+
+}
diff --git a/core/modules/language/lib/Drupal/language/Config/LanguageOverrideFileStorage.php b/core/modules/language/lib/Drupal/language/Config/LanguageOverrideFileStorage.php
deleted file mode 100644
index fa31003..0000000
--- a/core/modules/language/lib/Drupal/language/Config/LanguageOverrideFileStorage.php
+++ /dev/null
@@ -1,128 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\language\Config\LanguageOverrideFileStorage.
- */
-
-namespace Drupal\language\Config;
-
-use Drupal\Core\Cache\CacheBackendInterface;
-use Drupal\Core\Config\CachedStorage;
-use Drupal\Core\Config\FileStorage;
-
-/**
- * Defines file storage for language configuration overrides.
- */
-class LanguageOverrideFileStorage extends FileStorage implements LanguageOverrideStorageInterface {
-
-  /**
-   * The directory for the current language.
-   *
-   * @var string
-   */
-  protected $langcode;
-
-  /**
-   * The directory for the current language.
-   *
-   * @var string
-   */
-  protected $directory;
-
-  /**
-   * Tracks whether the directory exists to prevent excessive file system reads.
-   *
-   * @var bool
-   */
-  protected $directoryExists;
-
-  /**
-   * Constructs a new LanguageOverrideFileStorage.
-   */
-  public function __construct() {
-    // Do not call the parent as we do not yet have a directory.
-  }
-
-  /**
-   * Gets the override configuration directory for a language code.
-   *
-   * @param string $langcode
-   *   The language code to get the directory for.
-   *
-   * @return string
-   *   The directory where the language override configuration is stored.
-   */
-  protected function getDirectory($langcode) {
-    return config_get_config_directory(CONFIG_ACTIVE_DIRECTORY) . '/language/' . $langcode;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function write($name, array $data) {
-    $this->ensureDirectory();
-    return parent::write($name, $data);
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function delete($name) {
-    if ($this->hasDirectory()) {
-      return parent::delete($name);
-    }
-    return FALSE;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function listAll($prefix = '') {
-    if ($this->hasDirectory()) {
-      return parent::listAll($prefix);
-    }
-    return array();
-  }
-
-  /**
-   * Creates a directory if necessary.
-   */
-  protected function ensureDirectory() {
-    if (!$this->hasDirectory()) {
-      drupal_mkdir($this->directory, NULL, TRUE);
-      $this->directoryExists = TRUE;
-    }
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function setLangcode($langcode) {
-    // Reset directory check.
-    $this->directoryExists = NULL;
-    $this->langcode = $langcode;
-    $this->directory = $this->getDirectory($langcode);
-    if (empty($this->storage)) {
-      $this->storage = new FileStorage($this->directory);
-    }
-    else {
-      $this->storage->setDirectory($this->directory);
-    }
-    return $this;
-  }
-
-  /**
-   * Discovers is the directory for the language exists.
-   *
-   * @return bool
-   *   TRUE if the directory exists, FALSE if not.
-   */
-  protected function hasDirectory() {
-    if (!isset($this->directoryExists)) {
-      $this->directoryExists = is_dir($this->directory);
-    }
-    return $this->directoryExists;
-  }
-
-}
diff --git a/core/modules/language/lib/Drupal/language/Config/LanguageOverrideStorageInterface.php b/core/modules/language/lib/Drupal/language/Config/LanguageOverrideStorageInterface.php
index ba62497..f2a369a 100644
--- a/core/modules/language/lib/Drupal/language/Config/LanguageOverrideStorageInterface.php
+++ b/core/modules/language/lib/Drupal/language/Config/LanguageOverrideStorageInterface.php
@@ -7,7 +7,6 @@
 
 namespace Drupal\language\Config;
 
-use Drupal\Core\Config\StorageCacheInterface;
 use Drupal\Core\Config\StorageInterface;
 
 interface LanguageOverrideStorageInterface extends StorageInterface {
@@ -23,4 +22,18 @@
    */
   public function setLangcode($langcode);
 
+  /**
+   * Deletes all configuration in all languages for the given prefix.
+   *
+   * @param string $prefix
+   *   (optional) The prefix to search for. If omitted, all configuration
+   *   objects that exist will be deleted.
+   *
+   * @return boolean
+   *   TRUE on success, FALSE otherwise.
+   *
+   * @see \Drupal\Core\Config\StorageInterface::deleteAll()
+   */
+  public function deleteAllLanguages($prefix);
+
 }
diff --git a/core/tests/Drupal/Tests/Core/Config/CachedStorageTest.php b/core/tests/Drupal/Tests/Core/Config/CachedStorageTest.php
index f25a66f..6c60af4 100644
--- a/core/tests/Drupal/Tests/Core/Config/CachedStorageTest.php
+++ b/core/tests/Drupal/Tests/Core/Config/CachedStorageTest.php
@@ -84,41 +84,6 @@ public function testGetMultipleOnPrimedCache() {
   }
 
   /**
-   * Test that the cache prefix is used correctly.
-   */
-  public function testGetMultipleCachePrefix() {
-    $configNames = array(
-      'foo.bar',
-      'baz.back',
-    );
-    $configCacheValues = array(
-      'prefix:foo.bar' => array(
-        'foo' => 'bar',
-      ),
-      'prefix:baz.back' => array(
-        'foo' => 'bar',
-      ),
-    );
-    $configValues = array(
-      'foo.bar' => array(
-        'foo' => 'bar',
-      ),
-      'baz.back' => array(
-        'foo' => 'bar',
-      ),
-    );
-    $storage = $this->getMock('Drupal\Core\Config\StorageInterface');
-    $storage->expects($this->never())->method('readMultiple');
-    $cache = new MemoryBackend(__FUNCTION__);
-    foreach ($configCacheValues as $key => $value) {
-      $cache->set($key, $value);
-    }
-    $cachedStorage = new CachedStorage($storage, $cache);
-    $cachedStorage->setCachePrefix('prefix');
-    $this->assertEquals($configValues, $cachedStorage->readMultiple($configNames));
-  }
-
-  /**
    * Test fall through to file storage in CachedStorage::readMulitple().
    */
   public function testGetMultipleOnPartiallyPrimedCache() {
@@ -151,7 +116,7 @@ public function testGetMultipleOnPartiallyPrimedCache() {
     $storage = $this->getMock('Drupal\Core\Config\StorageInterface');
     $storage->expects($this->once())
       ->method('readMultiple')
-      ->with(array($configNames[2], $configNames[4]))
+      ->with(array(2 => $configNames[2], 4 => $configNames[4]))
       ->will($this->returnValue($response));
 
     $cachedStorage = new CachedStorage($storage, $cache);