Trying to Understand Upstream Keepalive

[Valentin V. Bartenev]

On Tuesday 14 June 2016 04:09:06 aanchalj wrote:
> As stated in
> http://nginx.org/en/docs/http/ngx_http_upstream_module.html#keepalive that
> "It should be particularly noted that the keepalive directive does not limit
> the total number of connections to upstream servers that an nginx worker
> process can open. The connections parameter should be set to a number small
> enough to let upstream servers process new incoming connections as well."  I
> want to understand if a new client comes, why can't they use existing
> keep-alive connections? Do they need to create a new connection with
> upstream?
> 
[..]

It's about the case when all of the existing keep-alive connections are already
in use and processing other client requests.

  wbr, Valentin V. Bartenev