为什么Lucene 2.4中的“删除文档"不起作用? [英] Why does 'delete document' in lucene 2.4 not work?

问题描述

我想用Java删除Lucene 2.4中的文档.我的代码是

I want to delete a document in lucene 2.4 with java. My code is

  Directory directory = FSDirectory.getDirectory("c:/index");
  IndexReader indexReader = IndexReader.open(directory);
  System.out.println("num="+indexReader.maxDoc());
  indexReader.deleteDocuments(new Term("name","1"));
  System.out.println("num="+indexReader.maxDoc());

 output 
         num=1
         num=1     

推荐答案

我认为最好使用Indexwriter删除文档，因为Indexreader 缓冲删除操作，并且不将更改写入到索引直到 close()被调用.除非您使用相同的参考进行搜索.

In my opinion it is best to use Indexwriter to delete the documents, since Indexreader buffers the deletions and does not write changes to the index until close() is called on.; unless you use the same reference for search.

Lucene Wiki 状态

通常最好使用IndexWriter 删除，除非

Generally it's best to use IndexWriter for deletions, unless

您必须按文件编号删除

您需要搜索以 立即反映出删除内容或

you need your searches to immediately reflect the deletions or

您必须知道多少个文件 已删除给定 deleteDocuments调用

you must know how many documents were deleted for a given deleteDocuments invocation

我可以看到您想要内存中文档的maxdoc值，因此它是使用Indexwriter的更好方法

I can see you want the maxdoc value for the document in memory so its a better approach to use Indexwriter

所以您的问题的答案是

您应该关闭Indexreader对象或使用Indexwriter进行删除

you should close the Indexreader object or use Indexwriter for deletions

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