###proxy settings start

proxy_http_version 1.1;

proxy_connect_timeout       3s;

proxy_read_timeout  3s;

proxy_send_timeout  3s;

proxy_buffer_size   128k;

proxy_buffers       256     16k;

proxy_busy_buffers_size     128k;

proxy_ignore_client_abort on;

###proxy settings end

语法：proxy_read_timeout time;

默认值：proxy_read_timeout 60s;

上下文：http，server，location

Defines a timeout for reading a response from the proxied server. The timeout is set only between two successive read operations, not for the transmission of the whole response. If the proxied server does not transmit anything within this time, the connection is closed.

需要注意的是，这个超时时间并不是针对单个请求的响应超时时间，而是针对两个成功响应之间的间隙，即如果被代理服务器在设置时间内没有发送任何数据，连接将被关闭

proxy_http_version设置为1.1，Nginx和被代理服务器之间默认使用长连接进行通信