php zend search lucene 优化

我的zend search lucene 代码你看看对你有帮助没？？？
function indexAction() {
$album = new Guestbook();
$view=new Zend_View();
$db = $album ->getAdapter();
$select =$db->query('SELECT * FROM st');
while($row = $select->fetch()) {
$user=$row['username'];
$pass=$row['password'];

$index = new Zend_Search_Lucene('index');

$doc = new Zend_Search_Lucene_Document();

// Store document URL to identify it in search result.
$doc->addField(Zend_Search_Lucene_Field::Text('username',$user));

// Index document content
$doc->addField(Zend_Search_Lucene_Field::Text('password',$pass));

// Add document to the index.
$index->addDocument($doc);

// Write changes to the index.
$index->commit();

//////

}

你这个貌似没有优化的部分么，最近我也在烦恼这个问题，zend lucene文档里面只有三个优化选项

1. MaxBufferedDocs auto-optimization op