         # File lib/ferret/index.rb, line 413
    413:     def query_delete(query)
    414:       @dir.synchronize do
    415:         ensure_searcher_open()
    416:         query = do_process_query(query)
    417:         @searcher.search_each(query) do |doc, score|
    418:           @reader.delete(doc)
    419:         end
    420:         flush() if @auto_flush
    421:       end
    422:     end