diff --git a/core/lib/Drupal/Core/Cache/CacheTagsChecksumInterface.php b/core/lib/Drupal/Core/Cache/CacheTagsChecksumInterface.php
index a140112..c9e3ff0 100644
--- a/core/lib/Drupal/Core/Cache/CacheTagsChecksumInterface.php
+++ b/core/lib/Drupal/Core/Cache/CacheTagsChecksumInterface.php
@@ -31,7 +31,7 @@
    * @param string[] $tags
    *   Array of cache tags.
    *
-   * @return int
+   * @return string
    *   Cache tag invalidations checksum.
    */
   public function getCurrentChecksum(array $tags);
diff --git a/core/lib/Drupal/Core/Cache/DatabaseBackend.php b/core/lib/Drupal/Core/Cache/DatabaseBackend.php
index 4610636..cc08cc5 100644
--- a/core/lib/Drupal/Core/Cache/DatabaseBackend.php
+++ b/core/lib/Drupal/Core/Cache/DatabaseBackend.php
@@ -481,10 +481,10 @@ public function schemaDefinition() {
           'not null' => FALSE,
         ),
         'checksum' => array(
-          'description' => 'The tag invalidation sum when this entry was saved.',
-          'type' => 'int',
+          'description' => 'The tag invalidation checksum when this entry was saved.',
+          'type' => 'varchar',
+          'length' => 255,
           'not null' => TRUE,
-          'default' => 0,
         ),
       ),
       'indexes' => array(