Too much logs are outputted

[ralf0131]

When the number of metrics reaches the upper limit, a warn log will be output every time:

[ WARN ] [2019-04-11 20:00:42] 65634a0c4570ce860ea9f5410eeedb3a- metrics size > 5000, a nop metric will be returned. name: middleware.tomcat.http.request.path{path=xxx.com/isExistNumber.do}

This might introduce the risk to fulfil the disk. Need to do some trick here. For example, output the warn message a few times and then stop.