问Lucene.net错误:在indexWriter.Optimize函数上读取超过EOF

EN

System.IO.IOException: read past EOF
at Lucene.Net.Store.BufferedIndexInput.Refill()
at Lucene.Net.Store.BufferedIndexInput.ReadByte()
at Lucene.Net.Store.IndexInput.ReadInt()
at Lucene.Net.Index.IndexWriter.ReadDeleteableFiles()
at Lucene.Net.Index.IndexWriter.DeleteSegments(ArrayList segments)
at Lucene.Net.Index.IndexWriter.MergeSegments(Int32 minSegment, Int32 end)
at Lucene.Net.Index.IndexWriter.FlushRamSegments()
at Lucene.Net.Index.IndexWriter.Optimize()

Analyzer analyzer = new StandardAnalyzer();
Lucene.Net.Store.Directory directory = FSDirectory.GetDirectory(lucenePath, false);

try
{
    IndexReader ir = IndexReader.Open(lucenePath);
    ir.DeleteDocuments(new Term("id", document.Lang + "-" + document.IDDoc));
    ir.Close();
}
catch (Exception) { }

IndexWriter iwriter;
try
{
    iwriter = new IndexWriter(directory, analyzer, false);
}
catch (Exception)
{
    iwriter = new IndexWriter(directory, analyzer, true);
}
iwriter.SetMaxFieldLength(25000);
Lucene.Net.Documents.Document doc = new Lucene.Net.Documents.Document();
doc.Add(new Lucene.Net.Documents.Field("content", fulltext, Lucene.Net.Documents.Field.Store.YES, Lucene.Net.Documents.Field.Index.TOKENIZED));
doc.Add(new Lucene.Net.Documents.Field("title", document.DocName, Lucene.Net.Documents.Field.Store.YES, Lucene.Net.Documents.Field.Index.TOKENIZED));
doc.Add(new Lucene.Net.Documents.Field("id", document.Lang + "-" + document.IDDoc, Lucene.Net.Documents.Field.Store.YES, Lucene.Net.Documents.Field.Index.UN_TOKENIZED));
iwriter.AddDocument(doc);
iwriter.Optimize();
iwriter.Close();
directory.Close();