         # File lib/ferret/index.rb, line 449
    449:     def query_delete(query)
    450:       @dir.synchrolock do
    451:         ensure_writer_open()
    452:         ensure_searcher_open()
    453:         query = do_process_query(query)
    454:         @searcher.search_each(query) do |doc, score|
    455:           @reader.delete(doc)
    456:         end
    457:         flush() if @auto_flush
    458:       end
    459:     end