Lucene IndexWriter.Close（）与indexWriter.Commit（）

Question

What is different between IndexWriter.Close() and IndexWriter.Commit() when I hava just single instance of indexWriter ?

Note :The Data that I going to make index is very big then I can't close IndexWriter runtime.

Note :I want to search in documents when data are indexing at sametime.

Answer 1

Commit() commits pending, buffered changes to the index (which can then be found with IndexReader() ). The IndexWriter can then continue to be used for more changes. Close() also performs a Commit(), but additionally closes the IndexWriter. Note that IndexWriter implements IDisposable(), and I recommend using it.

By your first note, if you mean there are lots of documents to index, that's fine. You can use the same IndexWriter for many documents without closing it. Just loop through however many documents you want to index within the same IndexWriter using() statement.

With regards to your second note, you must perform a commit() ( or close()) before your IndexWriter() changes will be seen by an IndexReader(). You can always search with IndexReader(), but it will only see the index as it was since the last IndexWriter.Commit().

I recommend Lucene In Action for these important details. It helped me a great deal.