$upstream_addr returning "-" only on requests with "del" in them

[ywarnier]

ru at nginx.com Wrote:

 [...]

> From the log it follows that client closed a connection before
> the entire request body was sent.  From the config it follows
> that http://nginx.org/r/proxy_request_buffering is "on" (which
> is the default setting).  It means that no upstream server was
> ever contacted, so it's perfectly okay that $upstream_addr is
> undefined (this is output as `-' in access_log).

Thanks.
Would there be a way I can get more info about *why* the client closed the
connection before the entire request body was sent? In the browser itself, I
can see the request being sent but it acts as if the server returned a
partial answer...

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,273895,273908#msg-273908