Extra cache operation in DBAL\Cache\ResultCacheStatement.php

public function closeCursor()
    {
        $this->statement->closeCursor();
        if ($this->emptied && $this->data !== null) {
            $data = $this->resultCache->fetch($this->cacheKey);
            if ( ! $data) {
                $data = array();
            }
            $data[$this->realKey] = $this->data;

            $this->resultCache->save($this->cacheKey, $data, $this->lifetime);
            unset($this->data);
        }
    }