Nginx日志基础

Nginx日志之 程序(脚本)的响应时间 upstream response time 和request time

request_time和$upstream_response_time

响应时间相关的一般有   $request_time 和  $upstream_response_time                                    
                           
$request_time包含了用户数据接收时间，而真正程序的响应时间应该用$upstream_response_time。

下面介绍下2者的差别：

1、request_time
官网描述：request processing time in seconds with a milliseconds resolution; time elapsed between the first bytes were read from the client and the log write after the last bytes were sent to the client 。
指的就是从接受用户请求的第一个字节到发送完响应数据的时间，即包括接收请求数据时间、程序响应时间、输出响应数据时间。

2、upstream_response_time
官网描述：keeps times of responses obtained from upstream servers; times are kept in seconds with a milliseconds resolution. Several response times are separated by commas and colons like addresses in the $upstream_addr variable是指从Nginx向后端（php-cgi)建立连接开始到接受完数据然后关闭连接为止的时间。

从上面的描述可以看出，$request_time肯定比$upstream_response_time值大，特别是使用POST方式传递参数时，因为Nginx会把request body缓存住，接受完毕后才会把数据一起发给后端。所以如果用户网络较差，或者传递数据较大时，$request_time会比$upstream_response_time大很多。

所以如果使用nginx的accesslog查看php程序中哪些接口比较慢的话，记得在log_format中加入$upstream_response_time。

程序哥想看脚本执行时间 于是 
#after
log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$upstream_response_time $status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

log_format  main_post  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for" "$request_body" $upstream_response_time';

参考

nginx log_format日志配置(转) http://blog.linuxchina.net/?p=2215

nginx优化之request_time 和upstream_response_time差别 http://wuzhangshu927.blog.163.com/blog/static/114224687201310674652147/