nginx日志request_time 和upstream_response_time区别

笔者在根据nginx的accesslog中$request_time进行程序优化时，发现有个接口，直接返回数据，平均的$request_time也比较大。原来$request_time包含了用户数据接收时间，而真正程序的响应时间应该用$upstream_response_time。

下面介绍下2者的差别：文章源自运维生存时间-https://www.ttlsa.com/nginx/nginx-logs-config-request_time-upstream_response_time/

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。文章源自运维生存时间-https://www.ttlsa.com/nginx/nginx-logs-config-request_time-upstream_response_time/

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文章源自运维生存时间-https://www.ttlsa.com/nginx/nginx-logs-config-request_time-upstream_response_time/

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。文章源自运维生存时间-https://www.ttlsa.com/nginx/nginx-logs-config-request_time-upstream_response_time/

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。文章源自运维生存时间-https://www.ttlsa.com/nginx/nginx-logs-config-request_time-upstream_response_time/

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。文章源自运维生存时间-https://www.ttlsa.com/nginx/nginx-logs-config-request_time-upstream_response_time/ 文章源自运维生存时间-https://www.ttlsa.com/nginx/nginx-logs-config-request_time-upstream_response_time/