Lucene OOM

Hi, all We have a search engine service built with lucene 4.7, it seem that lucene eat too much momery, and we have approximate 10 million document，the index size on disk is approximate 750G. My question is why the FST$Arc objects consume so much memory? please refer to the following histo sta

any api to get segment number of index

Hi, Is there any public API that I can get segment number of current version index? I didn't find in indexwriter or indexsearcher in lucene 4.10.