diff --git a/core/core.services.yml b/core/core.services.yml
index e4d2ece..0e8486f 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -6,7 +6,7 @@ services:
       - [setContainer, ['@service_container']]
   cache.backend.database:
     class: Drupal\Core\Cache\DatabaseBackendFactory
-    arguments: ['@database']
+    arguments: ['@database', '@cache.tag.database']
   cache.backend.memory:
     class: Drupal\Core\Cache\MemoryBackendFactory
   cache.bootstrap:
@@ -58,6 +58,9 @@ services:
     factory_method: get
     factory_service: cache_factory
     arguments: [path]
+  cache.tag.database:
+    class: Drupal\Core\Cache\DatabaseTag
+    arguments: ['@database']
   config.cachedstorage.storage:
     class: Drupal\Core\Config\FileStorage
     factory_class: Drupal\Core\Config\FileStorageFactory
diff --git a/core/lib/Drupal/Core/Cache/CacheTagBase.php b/core/lib/Drupal/Core/Cache/CacheTagBase.php
new file mode 100644
index 0000000..94ffb42
--- /dev/null
+++ b/core/lib/Drupal/Core/Cache/CacheTagBase.php
@@ -0,0 +1,71 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Cache\CacheTagBase.
+ */
+
+namespace Drupal\Core\Cache;
+
+/**
+ * Class CacheTagBase
+ */
+abstract class CacheTagBase implements CacheTagInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  abstract public function invalidateTags(array $tags);
+
+  /**
+   * {@inheritdoc}
+   */
+  abstract public function deleteTags(array $tags);
+
+  /**
+   * 'Flattens' a tags array into an array of strings.
+   *
+   * @param array $tags
+   *   Associative array of tags to flatten.
+   *
+   * @return array
+   *   An indexed array of flattened tag identifiers.
+   */
+  public function flattenTags(array $tags) {
+    if (isset($tags[0])) {
+      return $tags;
+    }
+
+    $flat_tags = array();
+    foreach ($tags as $namespace => $values) {
+      if (is_array($values)) {
+        foreach ($values as $value) {
+          $flat_tags[] = "$namespace:$value";
+        }
+      }
+      else {
+        $flat_tags[] = "$namespace:$values";
+      }
+    }
+    return $flat_tags;
+  }
+
+  /**
+   * Act on an exception when cache might be stale.
+   *
+   * If the cache_tags table does not yet exist, that's fine but if the table
+   * exists and yet the query failed, then the cache is stale and the
+   * exception needs to propagate.
+   *
+   * @param $e
+   *   The exception.
+   * @param string|null $table_name
+   *   The table name, defaults to $this->bin. Can be cache_tags.
+   */
+  protected function catchException(\Exception $e, $table_name = NULL) {
+    if ($this->connection->schema()->tableExists($table_name ?: $this->bin)) {
+      throw $e;
+    }
+  }
+
+}
diff --git a/core/lib/Drupal/Core/Cache/CacheTagInterface.php b/core/lib/Drupal/Core/Cache/CacheTagInterface.php
new file mode 100644
index 0000000..318e42e
--- /dev/null
+++ b/core/lib/Drupal/Core/Cache/CacheTagInterface.php
@@ -0,0 +1,37 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Cache\CacheTagInterface.
+ */
+
+namespace Drupal\Core\Cache;
+
+/**
+ * Class CacheTagInterface.
+ */
+interface CacheTagInterface {
+
+  /**
+   * Marks specified cache tags as deleted.
+   *
+   * If the cache items are being deleted because they are no longer "fresh",
+   * you may consider using invalidateTags() instead. This allows callers to
+   * retrieve the invalid items by calling get() with $allow_invalid set to TRUE.
+   * In some cases an invalid item may be acceptable rather than having to
+   * rebuild the cache.
+   *
+   * @param array $tags
+   *   Associative array of tags.
+   */
+  public function deleteTags(array $tags);
+
+  /**
+   * Marks specified cache tags as invalid.
+   *
+   * @param array $tags
+   *   Associative array of tags.
+   */
+  public function invalidateTags(array $tags);
+
+}
diff --git a/core/lib/Drupal/Core/Cache/DatabaseBackend.php b/core/lib/Drupal/Core/Cache/DatabaseBackend.php
index a45d338..3395ed4 100644
--- a/core/lib/Drupal/Core/Cache/DatabaseBackend.php
+++ b/core/lib/Drupal/Core/Cache/DatabaseBackend.php
@@ -24,7 +24,6 @@ class DatabaseBackend implements CacheBackendInterface {
    */
   protected $bin;
 
-
   /**
    * The database connection.
    *
@@ -33,21 +32,32 @@ class DatabaseBackend implements CacheBackendInterface {
   protected $connection;
 
   /**
+   * The cache tag service.
+   *
+   * @var \Drupal\Core\Cache\CacheTagInterface
+   */
+  protected $cacheTag;
+
+  /**
    * Constructs a DatabaseBackend object.
    *
    * @param \Drupal\Core\Database\Connection $connection
    *   The database connection.
+   * @param \Drupal\Core\Cache\CacheTagInterface
+   *   The cache tag service.
    * @param string $bin
    *   The cache bin for which the object is created.
    */
-  public function __construct(Connection $connection, $bin) {
+  public function __construct(Connection $connection, CacheTagInterface $cache_tag, $bin) {
     // All cache tables should be prefixed with 'cache_', except for the
     // default 'cache' bin.
     if ($bin != 'cache') {
       $bin = 'cache_' . $bin;
     }
     $this->bin = $bin;
+
     $this->connection = $connection;
+    $this->cacheTag = $cache_tag;
   }
 
   /**
@@ -110,7 +120,7 @@ protected function prepareItem($cache, $allow_invalid) {
 
     $cache->tags = $cache->tags ? explode(' ', $cache->tags) : array();
 
-    $checksum = $this->checksumTags($cache->tags);
+    $checksum = $this->cacheTag->checksumTags($cache->tags);
 
     // Check if deleteTags() has been called with any of the entry's tags.
     if ($cache->checksum_deletions != $checksum['deletions']) {
@@ -164,8 +174,8 @@ public function set($cid, $data, $expire = CacheBackendInterface::CACHE_PERMANEN
    * Actually set the cache.
    */
   protected function doSet($cid, $data, $expire, $tags) {
-    $flat_tags = $this->flattenTags($tags);
-    $checksum = $this->checksumTags($flat_tags);
+    $flat_tags = $this->cacheTag->flattenTags($tags);
+    $checksum = $this->cacheTag->checksumTags($flat_tags);
     $fields = array(
       'serialized' => 0,
       'created' => REQUEST_TIME,
@@ -218,20 +228,7 @@ public function deleteMultiple(array $cids) {
    * Implements Drupal\Core\Cache\CacheBackendInterface::deleteTags().
    */
   public function deleteTags(array $tags) {
-    $tag_cache = &drupal_static('Drupal\Core\Cache\CacheBackendInterface::tagCache', array());
-    foreach ($this->flattenTags($tags) as $tag) {
-      unset($tag_cache[$tag]);
-      try {
-        $this->connection->merge('cache_tags')
-          ->insertFields(array('deletions' => 1))
-          ->expression('deletions', 'deletions + 1')
-          ->key(array('tag' => $tag))
-          ->execute();
-      }
-      catch (\Exception $e) {
-        $this->catchException($e, 'cache_tags');
-      }
-    }
+    $this->cacheTag->deleteTags($tags);
   }
 
   /**
@@ -276,20 +273,7 @@ public function invalidateMultiple(array $cids) {
    * Implements Drupal\Core\Cache\CacheBackendInterface::invalidateTags().
    */
   public function invalidateTags(array $tags) {
-    try {
-      $tag_cache = &drupal_static('Drupal\Core\Cache\CacheBackendInterface::tagCache', array());
-      foreach ($this->flattenTags($tags) as $tag) {
-        unset($tag_cache[$tag]);
-        $this->connection->merge('cache_tags')
-          ->insertFields(array('invalidations' => 1))
-          ->expression('invalidations', 'invalidations + 1')
-          ->key(array('tag' => $tag))
-          ->execute();
-      }
-    }
-    catch (\Exception $e) {
-      $this->catchException($e, 'cache_tags');
-    }
+    $this->cacheTag->invalidateTags($tags);
   }
 
   /**
@@ -324,70 +308,6 @@ public function garbageCollection() {
   }
 
   /**
-   * 'Flattens' a tags array into an array of strings.
-   *
-   * @param array $tags
-   *   Associative array of tags to flatten.
-   *
-   * @return array
-   *   An indexed array of flattened tag identifiers.
-   */
-  protected function flattenTags(array $tags) {
-    if (isset($tags[0])) {
-      return $tags;
-    }
-
-    $flat_tags = array();
-    foreach ($tags as $namespace => $values) {
-      if (is_array($values)) {
-        foreach ($values as $value) {
-          $flat_tags[] = "$namespace:$value";
-        }
-      }
-      else {
-        $flat_tags[] = "$namespace:$values";
-      }
-    }
-    return $flat_tags;
-  }
-
-  /**
-   * Returns the sum total of validations for a given set of tags.
-   *
-   * @param array $tags
-   *   Array of flat tags.
-   *
-   * @return int
-   *   Sum of all invalidations.
-   *
-   * @see Drupal\Core\Cache\DatabaseBackend::flattenTags()
-   */
-  protected function checksumTags($flat_tags) {
-    $tag_cache = &drupal_static('Drupal\Core\Cache\CacheBackendInterface::tagCache', array());
-
-    $checksum = array(
-      'invalidations' => 0,
-      'deletions' => 0,
-    );
-
-    $query_tags = array_diff($flat_tags, array_keys($tag_cache));
-    if ($query_tags) {
-      $db_tags = $this->connection->query('SELECT tag, invalidations, deletions FROM {cache_tags} WHERE tag IN (:tags)', array(':tags' => $query_tags))->fetchAllAssoc('tag', \PDO::FETCH_ASSOC);
-      $tag_cache += $db_tags;
-
-      // Fill static cache with empty objects for tags not found in the database.
-      $tag_cache += array_fill_keys(array_diff($query_tags, array_keys($db_tags)), $checksum);
-    }
-
-    foreach ($flat_tags as $tag) {
-      $checksum['invalidations'] += $tag_cache[$tag]['invalidations'];
-      $checksum['deletions'] += $tag_cache[$tag]['deletions'];
-    }
-
-    return $checksum;
-  }
-
-  /**
    * Implements Drupal\Core\Cache\CacheBackendInterface::isEmpty().
    */
   public function isEmpty() {
diff --git a/core/lib/Drupal/Core/Cache/DatabaseBackendFactory.php b/core/lib/Drupal/Core/Cache/DatabaseBackendFactory.php
index e118932..a88af47 100644
--- a/core/lib/Drupal/Core/Cache/DatabaseBackendFactory.php
+++ b/core/lib/Drupal/Core/Cache/DatabaseBackendFactory.php
@@ -19,12 +19,20 @@ class DatabaseBackendFactory {
   protected $connection;
 
   /**
+   * The cache tag service.
+   *
+   * @var \Drupal\Core\Cache\CacheTagInterface
+   */
+  protected $cacheTag;
+
+  /**
    * Constructs the DatabaseBackendFactory object.
    *
    * @param \Drupal\Core\Database\Connection $connection
    */
-  function __construct(Connection $connection) {
+  function __construct(Connection $connection, CacheTagInterface $cache_tag) {
     $this->connection = $connection;
+    $this->cacheTag = $cache_tag;
   }
 
   /**
@@ -37,7 +45,7 @@ function __construct(Connection $connection) {
    *   The cache backend object for the specified cache bin.
    */
   function get($bin) {
-    return new DatabaseBackend($this->connection, $bin);
+    return new DatabaseBackend($this->connection, $this->cacheTag, $bin);
   }
 
 }
diff --git a/core/lib/Drupal/Core/Cache/DatabaseTag.php b/core/lib/Drupal/Core/Cache/DatabaseTag.php
new file mode 100644
index 0000000..4f6d99a
--- /dev/null
+++ b/core/lib/Drupal/Core/Cache/DatabaseTag.php
@@ -0,0 +1,113 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Cache\DatabaseTag.
+ */
+
+namespace Drupal\Core\Cache;
+
+use Drupal\Core\Database\Connection;
+
+/**
+ * Class DatabaseTag.
+ */
+class DatabaseTag extends CacheTagBase {
+
+  /**
+   * The database connection.
+   *
+   * @var \Drupal\Core\Database\Connection
+   */
+  protected $connection;
+
+  /**
+   * A static cache of tags.
+   *
+   * @var array
+   */
+  protected $tagCache = array();
+
+  /**
+   * Constructs a DatabaseTag object.
+   *
+   * @param \Drupal\Core\Database\Connection $connection
+   *   The database connection.
+   */
+  public function __construct(Connection $connection) {
+    $this->connection = $connection;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function invalidateTags(array $tags) {
+    try {
+      foreach ($this->flattenTags($tags) as $tag) {
+        unset($this->tagCache[$tag]);
+        $this->connection->merge('cache_tags')
+          ->insertFields(array('invalidations' => 1))
+          ->expression('invalidations', 'invalidations + 1')
+          ->key(array('tag' => $tag))
+          ->execute();
+      }
+    }
+    catch (\Exception $e) {
+      $this->catchException($e, 'cache_tags');
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function deleteTags(array $tags) {
+    foreach ($this->flattenTags($tags) as $tag) {
+      unset($this->tagCache[$tag]);
+      try {
+        $this->connection->merge('cache_tags')
+          ->insertFields(array('deletions' => 1))
+          ->expression('deletions', 'deletions + 1')
+          ->key(array('tag' => $tag))
+          ->execute();
+      }
+      catch (\Exception $e) {
+        $this->catchException($e, 'cache_tags');
+      }
+    }
+  }
+
+  /**
+   * Returns the sum total of validations for a given set of tags.
+   *
+   * @param array $tags
+   *   Array of flat tags.
+   *
+   * @return int
+   *   Sum of all invalidations.
+   *
+   * @see Drupal\Core\Cache\DatabaseBackend::flattenTags()
+   */
+  public function checksumTags($flat_tags) {
+    $checksum = array(
+      'invalidations' => 0,
+      'deletions' => 0,
+    );
+
+    $query_tags = array_diff($flat_tags, array_keys($this->tagCache));
+    if ($query_tags) {
+      $db_tags = $this->connection->query('SELECT tag, invalidations, deletions FROM {cache_tags} WHERE tag IN (:tags)', array(':tags' => $query_tags))->fetchAllAssoc('tag', \PDO::FETCH_ASSOC);
+      $this->tagCache += $db_tags;
+
+      // Fill static cache with empty objects for tags not found in the database.
+      $this->tagCache += array_fill_keys(array_diff($query_tags, array_keys($db_tags)), $checksum);
+    }
+
+    foreach ($flat_tags as $tag) {
+      $checksum['invalidations'] += $this->tagCache[$tag]['invalidations'];
+      $checksum['deletions'] += $this->tagCache[$tag]['deletions'];
+    }
+
+    return $checksum;
+  }
+
+}
diff --git a/core/modules/system/lib/Drupal/system/Tests/Cache/DatabaseBackendUnitTest.php b/core/modules/system/lib/Drupal/system/Tests/Cache/DatabaseBackendUnitTest.php
index 3b607a5..62042cc 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Cache/DatabaseBackendUnitTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Cache/DatabaseBackendUnitTest.php
@@ -37,7 +37,7 @@ public static function getInfo() {
    *   A new DatabaseBackend object.
    */
   protected function createCacheBackend($bin) {
-    return new DatabaseBackend($this->container->get('database'), $bin);
+    return new DatabaseBackend($this->container->get('database'), $this->container->get('cache.tag.database'), $bin);
   }
 
 }