diff --git a/core/lib/Drupal/Core/Cache/DatabaseTag.php b/core/lib/Drupal/Core/Cache/DatabaseTag.php
index 2f3fef3..a7aa41b 100644
--- a/core/lib/Drupal/Core/Cache/DatabaseTag.php
+++ b/core/lib/Drupal/Core/Cache/DatabaseTag.php
@@ -22,13 +22,6 @@ class DatabaseTag extends CacheTagBase {
   protected $connection;
 
   /**
-   * A static cache of tags.
-   *
-   * @var array
-   */
-  protected $tagCache = array();
-
-  /**
    * Constructs a DatabaseTag object.
    *
    * @param \Drupal\Core\Database\Connection $connection
@@ -61,8 +54,9 @@ public function invalidateTags(array $tags) {
    * {@inheritdoc}
    */
   public function deleteTags(array $tags) {
+    $tagCache = &drupal_static('Drupal\Core\Cache\DatabaseTag::tagCache', array());
     foreach ($this->flattenTags($tags) as $tag) {
-      unset($this->tagCache[$tag]);
+      unset($tagCache[$tag]);
       try {
         $this->connection->merge('cache_tags')
           ->insertFields(array('deletions' => 1))
@@ -88,23 +82,25 @@ public function deleteTags(array $tags) {
    * @see Drupal\Core\Cache\DatabaseBackend::flattenTags()
    */
   public function checksumTags($flat_tags) {
+    $tagCache = &drupal_static('Drupal\Core\Cache\DatabaseTag::tagCache', array());
+
     $checksum = array(
       'invalidations' => 0,
       'deletions' => 0,
     );
 
-    $query_tags = array_diff($flat_tags, array_keys($this->tagCache));
+    $query_tags = array_diff($flat_tags, array_keys($tagCache));
     if ($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;
+      $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);
+      $tagCache += array_fill_keys(array_diff($query_tags, array_keys($db_tags)), $checksum);
     }
 
     foreach ($flat_tags as $tag) {
-      $checksum['invalidations'] += $this->tagCache[$tag]['invalidations'];
-      $checksum['deletions'] += $this->tagCache[$tag]['deletions'];
+      $checksum['invalidations'] += $tagCache[$tag]['invalidations'];
+      $checksum['deletions'] += $tagCache[$tag]['deletions'];
     }
 
     return $checksum;
diff --git a/core/modules/locale/lib/Drupal/locale/Tests/LocaleTranslationUiTest.php b/core/modules/locale/lib/Drupal/locale/Tests/LocaleTranslationUiTest.php
index 06b6ed4..f18602c 100644
--- a/core/modules/locale/lib/Drupal/locale/Tests/LocaleTranslationUiTest.php
+++ b/core/modules/locale/lib/Drupal/locale/Tests/LocaleTranslationUiTest.php
@@ -148,7 +148,7 @@ function testStringTranslation() {
 
     // Reset the tag cache on the tester side in order to pick up the call to
     // cache()->deleteTags() on the tested side.
-    drupal_static_reset('Drupal\Core\Cache\CacheBackendInterface::tagCache');
+    drupal_static_reset('Drupal\Core\Cache\DatabaseTag::tagCache');
 
     $this->assertTrue($name != $translation && t($name, array(), array('langcode' => $langcode)) == $translation, 't() works for non-English.');
     // Refresh the locale() cache to get fresh data from t() below. We are in
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
index a4c7b27..37c4af4 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
@@ -1006,7 +1006,7 @@ protected function refreshVariables() {
     cache('bootstrap')->delete('variables');
     $conf = variable_initialize();
     // Clear the tag cache.
-    drupal_static_reset('Drupal\Core\Cache\CacheBackendInterface::tagCache');
+    drupal_static_reset('Drupal\Core\Cache\DatabaseTag::tagCache');
     \Drupal::service('config.factory')->reset();
   }