Metrics of total_net_output_bytes and instantaneous_output_kbps are wrong

[Gen Liu]

Recently I noticed that the traffic of a redis server is significant higher than normal(at about 2GB/s) and 

is about to exceed the hardware limits. I searched around and found many people are facing this problem.

So I dig into the code and find there is a bug. and here are the details:

Redis counts more bytes than it actually wrote when dealing with pending replies, and this would make 

metrics of instantaneous_output_kbps and total_net_output_bytes increase very fast.  

In src/networking.c writeToClient function:

while(clientHasPendingReplies(c)) {
    //...
    nwritten = write(/*...*/);
    totwritten += nwritten;
    //...
    server.stat_net_output_bytes += totwritten;
}

totwritten is counted(and not reset) each time the loop runs.  

 BTW I made a pull request on Github.

[Gen Liu]

this bug has been fixed yesterday.

在 2017年6月20日星期二 UTC+8下午2:50:40，Gen Liu写道：