Apply fixed review.

framework/data/ActiveDataProvider.php

@@ -156,8 +156,6 @@ protected function prepareKeys($models)
         return array_keys($models);
     }
 
-    private $_totalCount = [];
-
     /**
      * {@inheritdoc}
      */
@@ -166,13 +164,8 @@ protected function prepareTotalCount()
         if (!$this->query instanceof QueryInterface) {
             throw new InvalidConfigException('The "query" property must be an instance of a class that implements the QueryInterface e.g. yii\db\Query or its subclasses.');
         }
-        $query = (clone $this->query)->limit(-1)->offset(-1)->orderBy([]);
-        $key = md5((string)$query);
-
-        if (!array_key_exists($key, $this->_totalCount)) {
-            $this->_totalCount[$key] = (int)$query->count('*', $this->db);
-        }
-        return $this->_totalCount[$key];
+        $query = clone $this->query;
+        return (int) $query->limit(-1)->offset(-1)->orderBy([])->count('*', $this->db);
     }
 
     /**