为什么不删除未使用的段文件?

I don't know what changed--things were working relatively well with our Lucene implementation. But now, the number of files in the index directory just keeps growing. It started with _0 files, then _1 files appeared, then _2 and _3 files. I am passing in false to the IndexWriter's constructor for the 'create' parameter, if there are existing files in that directory when it begins:I don't know what changed--things were working