what's bad basex ? slow insert doc after continuesly add/insert, lost db access..

Hi,all, after continuesly insert/add doc to basex db up to 80000 file with restxq web service, there are some nonsens result: very slow for insert/add doc to db. some time can't list db in basex cmd line. after restart ,it's ok. and this will cause the xquery can't work like collection('db/path')//.., say something like: can't found resource ..../webapp/db . who can give some reason or what 's wrong with me? Thanks.