Do not perform VACUUM on SQLITE database when clearing system cache?

[yjmtmtk]

$app->on('app.system.cache.flush', function() use ($app) {
    $data_dir = $app->paths['#storage'][0] . 'data';
    $backup_dir = $data_dir . '_backup';
    if (!file_exists($backup_dir)) {
        mkdir($backup_dir, 0777, true);
    }
    $files = glob($data_dir . '/*.sqlite');
    foreach ($files as $file) {
        try {
            $backup_file = $backup_dir . '/' . basename($file) . '.backup';
            copy($file, $backup_file);
            $db = new SQLite3($file);
            $result = $db->exec('VACUUM');
            $db->close();
            if ($result === false) {
                copy($backup_file, $file);
            }
            unlink($backup_file);
        } catch (Exception $e) {
            
        }
    }
    if (is_dir($backup_dir)) {
        $backup_files = glob($backup_dir . '/*');
        foreach ($backup_files as $file) {
            unlink($file);
        }
        rmdir($backup_dir);
    }
});