diff --git a/core/modules/field/modules/field_sql_storage/field_sql_storage.module b/core/modules/field/modules/field_sql_storage/field_sql_storage.module
index 26b2ba8..85cd085 100644
--- a/core/modules/field/modules/field_sql_storage/field_sql_storage.module
+++ b/core/modules/field/modules/field_sql_storage/field_sql_storage.module
@@ -191,7 +191,15 @@ function _field_sql_storage_schema($field) {
   foreach ($field['indexes'] as $index_name => $columns) {
     $real_name = _field_sql_storage_indexname($field['field_name'], $index_name);
     foreach ($columns as $column_name) {
-      $current['indexes'][$real_name][] = _field_sql_storage_columnname($field['field_name'], $column_name);
+      if (is_array($column_name)) {
+        $current['indexes'][$real_name][] = array(
+          _field_sql_storage_columnname($field['field_name'], $column_name[0]),
+          $column_name[1],
+        );
+      }
+      else {
+        $current['indexes'][$real_name][] = _field_sql_storage_columnname($field['field_name'], $column_name);
+      }
     }
   }
 
@@ -300,7 +308,15 @@ function field_sql_storage_field_storage_update_field($field, $prior_field, $has
         $real_name = _field_sql_storage_indexname($field['field_name'], $name);
         $real_columns = array();
         foreach ($columns as $column_name) {
-          $real_columns[] = _field_sql_storage_columnname($field['field_name'], $column_name);
+          if (is_array($column_name)) {
+            $real_columns[] = array(
+              _field_sql_storage_columnname($field['field_name'], $column_name[0]),
+              $column_name[1],
+            );
+          }
+          else {
+            $real_columns[] = _field_sql_storage_columnname($field['field_name'], $column_name);
+          }
         }
         db_add_index($table, $real_name, $real_columns);
         db_add_index($revision_table, $real_name, $real_columns);
diff --git a/core/modules/field/modules/field_sql_storage/lib/Drupal/field_sql_storage/Tests/FieldSqlStorageTest.php b/core/modules/field/modules/field_sql_storage/lib/Drupal/field_sql_storage/Tests/FieldSqlStorageTest.php
index 2e9070d..3cabd58 100644
--- a/core/modules/field/modules/field_sql_storage/lib/Drupal/field_sql_storage/Tests/FieldSqlStorageTest.php
+++ b/core/modules/field/modules/field_sql_storage/lib/Drupal/field_sql_storage/Tests/FieldSqlStorageTest.php
@@ -372,14 +372,14 @@ function testFieldUpdateIndexesWithData() {
     field_attach_insert('test_entity', $entity);
 
     // Add an index
-    $field = array('field_name' => $field_name, 'indexes' => array('value' => array('value')));
+    $field = array('field_name' => $field_name, 'indexes' => array('value' => array(array('value', 255))));
     field_update_field($field);
     foreach ($tables as $table) {
       $this->assertTrue(Database::getConnection()->schema()->indexExists($table, "{$field_name}_value"), t("Index on value created in $table"));
     }
 
     // Add a different index, removing the existing custom one.
-    $field = array('field_name' => $field_name, 'indexes' => array('value_format' => array('value', 'format')));
+    $field = array('field_name' => $field_name, 'indexes' => array('value_format' => array(array('value', 127), array('format', 127))));
     field_update_field($field);
     foreach ($tables as $table) {
       $this->assertTrue(Database::getConnection()->schema()->indexExists($table, "{$field_name}_value_format"), t("Index on value_format created in $table"));