每次运行Lucene索引时，它都会变得越来越慢

Question

此代码使用Lucene.NET测试索引。

for (int i = 0; i < 10; i++) 
{ 
    var stopwatch = Stopwatch.StartNew(); 
    string indexPath = Path.Combine("C:\\lucene\\"); 
    var directory = FSDirectory.Open(new DirectoryInfo(indexPath)); 
    var analyzer = new StandardAnalyzer(LuceneConfiguration.Version); 

    IndexWriter indexWriter = null; 
    try 
    { 
     indexWriter = new IndexWriter(directory, analyzer, true, 
             IndexWriter.MaxFieldLength.UNLIMITED); 
     indexWriter.DeleteAll(); 

     for (int documentNumber = 0; documentNumber < 100; documentNumber++) 
     { 
      var document = new Document(); 
      for (int fieldNumber = 0; fieldNumber < 10; fieldNumber++) 
      { 
       document.Add(new Field("Field" + fieldNumber, "asdf qwerty Value" + fieldNumber, Field.Store.YES, 
             Field.Index.ANALYZED)); 
      } 
      indexWriter.AddDocument(document); 
     } 

     indexWriter.Optimize(); 
    } 
    finally 
    { 
     if (indexWriter != null) 
     { 
      indexWriter.Close(); 
     } 
    } 
    stopwatch.Stop(); 
    Console.WriteLine("Index time: " + stopwatch.Elapsed.TotalMilliseconds); 


    var reader = IndexReader.Open(directory, true); 
    var searcher = new IndexSearcher(reader); 
    var parser = new QueryParser(LuceneConfiguration.Version, "Field0", analyzer); 

    var query = parser.Parse("asdf"); 

    var collector = TopScoreDocCollector.create(10, true); 

    searcher.Search(query, collector); 

    Console.WriteLine("Hits: " + collector.GetTotalHits()); 
} 

Console.ReadKey(); 

对于每次索引运行时，索引变得越来越慢。如果我在索引后跳过搜索，它不会变慢。这只发生在我用调试开始时。不，如果我没有调试就启动它。

什么可能导致这种情况？

Answer 1

我在想，如果这是第一次在Lucene尝试自动清除索引目录时发生IOException异常。这些会发生，因为您的读者/搜索者仍然处于打开状态，并锁定段文件以进行删除。