    # File lib/active_support/vendor/memcache-client-1.5.0/memcache.rb, line 377
      def delete(key, expiry = 0)
        @mutex.lock if @multithread

        raise MemCacheError, "No active servers" unless active?
        cache_key = make_cache_key key
        server = get_server_for_key cache_key

        sock = server.socket
        raise MemCacheError, "No connection to server" if sock.nil?

        begin
          sock.write "delete #{cache_key} #{expiry}\r\n"
          result = sock.gets
          raise_on_error_response! result
          result
        rescue SocketError, SystemCallError, IOError => err
          server.close
          raise MemCacheError, err.message
        end
      ensure
        @mutex.unlock if @multithread
      end