In Batch processing Zend_Search opens to many files - this results in message 'Index is under processing now'

So that the index is not usable anymore.

{quote} Warning: Zend_Search_Lucene_Storage_File_Filesystem::require_once(Zend/Search/Lucene/Exception.php): failed to open stream: Too many open files in /search/Zend/Search/Lucene/Storage/File/Filesystem.php on line 65

Fatal error: Zend_Search_Lucene_Storage_File_Filesystem::require_once(): Failed opening required 'Zend/Search/Lucene/Exception.php' (include_path='.:/usr/share/php:/usr/share/pear') in /search/Zend/Search/Lucene/Storage/File/Filesystem.php on line 65

Fatal error: Uncaught exception 'Zend_Search_Lucene_Exception' with message 'Index is under processing now' in /search/Zend/Search/Lucene.php:266 Stack trace:

0 /search/Zend/Search/Lucene.php(508): Zend_Search_Lucene::getActualGeneration(Object(Zend_Search_Lucene_Storage_Directory_Filesystem))

1 /search/Zend/Search/Lucene.php(211): Zend_Search_Lucene->__construct('./ram/Index', false)

2 /search/search.helper-wo-shm.php(204): Zend_Search_Lucene::open('./ram/Index')

3 /search/work-manager.php(39): update_group('test...')

4 {main}

thrown in /search/Zend/Search/Lucene.php on line 266 {quote}

This is with the curent SVN and 1.8.0