diff --git a/core/lib/Drupal/Core/Cache/CacheBackendInterface.php b/core/lib/Drupal/Core/Cache/CacheBackendInterface.php
index 50c5d4d..f604980 100644
--- a/core/lib/Drupal/Core/Cache/CacheBackendInterface.php
+++ b/core/lib/Drupal/Core/Cache/CacheBackendInterface.php
@@ -99,7 +99,7 @@ public function set($cid, $data, $expire = Cache::PERMANENT, array $tags = array
    * Store multiple items in the persistent cache.
    *
    * @param array $items
-   *   An array of cache items in the form:
+   *   An array of cache items, keyed by cid. In the form:
    *   @code
    *   $items = array(
    *     $cid => array(
diff --git a/core/lib/Drupal/Core/Cache/DatabaseBackend.php b/core/lib/Drupal/Core/Cache/DatabaseBackend.php
index 28ce6e7..016fbdd 100644
--- a/core/lib/Drupal/Core/Cache/DatabaseBackend.php
+++ b/core/lib/Drupal/Core/Cache/DatabaseBackend.php
@@ -205,33 +205,70 @@ protected function doSet($cid, $data, $expire, $tags) {
    * {@inheritdoc}
    */
   public function setMultiple(array $items) {
+    $deleted_tags = &drupal_static('Drupal\Core\Cache\DatabaseBackend::deletedTags', array());
+    $invalidated_tags = &drupal_static('Drupal\Core\Cache\DatabaseBackend::invalidatedTags', array());
+
     // Use a transaction so that the database can write the changes in a single
     // commit.
     $transaction = $this->connection->startTransaction();
-    $this->deleteMultiple(array_keys($items));
-    $query = $this->connection
-      ->insert($this->bin)
-      ->fields(array('cid', 'data', 'expire', 'created', 'serialized', 'tags', 'checksum_invalidations', 'checksum_deletions'));
-    foreach ($items as $cid => $item) {
-      $item += array(
-        'expire' => CacheBackendInterface::CACHE_PERMANENT,
-        'tags' => array(),
-      );
-      $flat_tags = $this->flattenTags($item['tags']);
-      $checksum = $this->checksumTags($flat_tags);
-      $fields = array(
-        'cid' => $cid,
-        'data' => is_string($item['data']) ? $item['data'] : serialize($item['data']),
-        'expire' => $item['expire'],
-        'created' => REQUEST_TIME,
-        'serialized' => is_string($item['data']) ? 0 : 1,
-        'tags' => implode(' ', $flat_tags),
-        'checksum_invalidations' => $checksum['invalidations'],
-        'checksum_deletions' => $checksum['deletions'],
-      );
-      $query->values($fields);
-    }
-    $query->execute();
+
+    try {
+      $this->deleteMultiple(array_keys($items));
+
+      $query = $this->connection
+        ->insert($this->bin)
+        ->fields(array('cid', 'data', 'expire', 'created', 'serialized', 'tags', 'checksum_invalidations', 'checksum_deletions'));
+
+      foreach ($items as $cid => $item) {
+        $item += array(
+          'expire' => CacheBackendInterface::CACHE_PERMANENT,
+          'tags' => array(),
+        );
+
+        $flat_tags = $this->flattenTags($item['tags']);
+
+        // Remove tags that were already deleted or invalidated during this request
+        // from the static caches so that another deletion or invalidation can
+        // occur.
+        foreach ($flat_tags as $tag) {
+          if (isset($deleted_tags[$tag])) {
+            unset($deleted_tags[$tag]);
+          }
+          if (isset($invalidated_tags[$tag])) {
+            unset($invalidated_tags[$tag]);
+          }
+        }
+
+        $checksum = $this->checksumTags($flat_tags);
+
+        $fields = array(
+          'cid' => $cid,
+          'expire' => $item['expire'],
+          'created' => REQUEST_TIME,
+          'tags' => implode(' ', $flat_tags),
+          'checksum_invalidations' => $checksum['invalidations'],
+          'checksum_deletions' => $checksum['deletions'],
+        );
+
+        if (!is_string($item['data'])) {
+          $fields['data'] = serialize($item['data']);
+          $fields['serialized'] = 1;
+        }
+        else {
+          $fields['data'] = $item['data'];
+          $fields['serialized'] = 0;
+        }
+
+        $query->values($fields);
+      }
+
+      $query->execute();
+    }
+    catch (\Exception $e) {
+      $transaction->rollback();
+      // @todo Log something here or just re throw?
+      throw $e;
+    }
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Cache/MemoryBackend.php b/core/lib/Drupal/Core/Cache/MemoryBackend.php
index ff4cf59..fb9e29c 100644
--- a/core/lib/Drupal/Core/Cache/MemoryBackend.php
+++ b/core/lib/Drupal/Core/Cache/MemoryBackend.php
@@ -205,11 +205,11 @@ protected function flattenTags(array $tags) {
     foreach ($tags as $namespace => $values) {
       if (is_array($values)) {
         foreach ($values as $value) {
-          $flat_tags["$namespace:$value"] = "$namespace:$value";
+          $flat_tags[] = "$namespace:$value";
         }
       }
       else {
-        $flat_tags["$namespace:$values"] = "$namespace:$values";
+        $flat_tags[] = "$namespace:$values";
       }
     }
     return $flat_tags;
diff --git a/core/modules/system/lib/Drupal/system/Tests/Cache/GenericCacheBackendUnitTestBase.php b/core/modules/system/lib/Drupal/system/Tests/Cache/GenericCacheBackendUnitTestBase.php
index 0704ec7..da28fc4 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Cache/GenericCacheBackendUnitTestBase.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Cache/GenericCacheBackendUnitTestBase.php
@@ -8,6 +8,7 @@
 namespace Drupal\system\Tests\Cache;
 
 use Drupal\Core\Cache\Cache;
+use Drupal\Core\Cache\CacheBackendInterface;
 use Drupal\simpletest\DrupalUnitTestBase;
 
 /**
@@ -301,17 +302,35 @@ public function testGetMultiple() {
   public function testSetMultiple() {
     $backend = $this->getCacheBackend();
 
-    // Set numerous testing keys.
+    $future_expiration = REQUEST_TIME + 100;
+
+    // Set multiple testing keys.
     $backend->set('cid_1', 'Some other value');
     $items = array(
       'cid_1' => array('data' => 1),
       'cid_2' => array('data' => 2),
+      'cid_3' => array('data' => array(1, 2)),
+      'cid_4' => array('data' => 1, 'expire' => $future_expiration),
+      'cid_5' => array('data' => 1, 'tags' => array('test' => array('a', 'b'))),
     );
     $backend->setMultiple($items);
     $cids = array_keys($items);
     $cached = $backend->getMultiple($cids);
+
     $this->assertEqual($cached['cid_1']->data, $items['cid_1']['data'], 'Over-written cache item set correctly.');
+    $this->assertEqual($cached['cid_1']->expire, CacheBackendInterface::CACHE_PERMANENT, 'Cache expiration defaults to permanent.');
+
     $this->assertEqual($cached['cid_2']->data, $items['cid_2']['data'], 'New cache item set correctly.');
+    $this->assertEqual($cached['cid_2']->expire, CacheBackendInterface::CACHE_PERMANENT, 'Cache expiration defaults to permanent.');
+
+    $this->assertEqual($cached['cid_3']->data, $items['cid_3']['data'], 'New cache item with serialized data set correctly.');
+    $this->assertEqual($cached['cid_3']->expire, CacheBackendInterface::CACHE_PERMANENT, 'Cache expiration defaults to permanent.');
+
+    $this->assertEqual($cached['cid_4']->data, $items['cid_4']['data'], 'New cache item set correctly.');
+    $this->assertEqual($cached['cid_4']->expire, $future_expiration, 'Cache expiration has been correctly set.');
+
+    $this->assertEqual($cached['cid_5']->data, $items['cid_5']['data'], 'New cache item set correctly.');
+    $this->assertEqual($cached['cid_5']->tags, array('test:a', 'test:b'));
   }
 
   /**