I check implementation. in SegmentMerger.mergeFieldInfos
public void mergeFieldInfos() throws IOException { for (AtomicReader reader : mergeState.readers) { FieldInfos readerFieldInfos = reader.getFieldInfos(); for (FieldInfo fi : readerFieldInfos) { fieldInfosBuilder.add(fi); } } mergeState.fieldInfos = fieldInfosBuilder.finish(); } we do not check if the field still use in new documents. We just add all existing fields to new segments field. Will we fix this issue? Thanks, Yongtao -- View this message in context: http://lucene.472066.n3.nabble.com/solr-optimize-on-fnm-file-tp4134969p4134972.html Sent from the Solr - User mailing list archive at Nabble.com.