Re: [libmicrohttpd] MHD threading models: what model is similar to Least Connected?

[Evgeny Grin]

It's a basic of theory of mass telecommunication.
Developed with first automatic telephone exchange.
In overloaded situation - just reject some part of incoming traffic as
retries only prevent end of overload.

You can do it manually.
Start MHD with MHD_USE_NO_LISTEN_SOCKET and process polling of listen
socket in your own thread. Use MHD_add_connection() when new connection
arrive.
As soon as you detect "overload" of MHD - start new MHD instance without
listen socket and use MHD_add_connection() with new MHD instance.

-- 
Best Wishes,
Evgeny Grin

On 01.12.2016 23:13, silvioprog wrote:
> Hello,
> 
> Please take a look at this quote:
> 
> "*/Least Connected/*
> /
> /
> /With least connected load balancing, nginx won’t forward any traffic to
> a busy server. This method is useful when operations on the application
> servers take longer to complete. Using this method helps to avoid
> overload situations, because nginx doesn't pass any requests to servers
> which are already under load./"
> 
> See article:
> https://futurestud.io/tutorials/nginx-load-balancing-advanced-configuration
> .
> 
> I'm using this nginx feature and it helped me a lot: I have an
> application with two routes, the first one is fast because it just
> process common atomic CRUD operations; the second is a little bit slow,
> because that spends a long time processing hard things like report
> generation. So I start two instances of my application and configuring
> two proxies in my upstream, all the time the requests are redirected to
> the first proxy, but when some request executes some reporting
> generation -- blocking the server --, all next requests are redirected
> to the second proxy, however, after a timeout (about 10 seconds), the
> server checks if the first proxy is readable, coming back the requests
> for the first one.
> 
> Does MHD offer something like this on its threading models? It so, what
> flags I need to pass to get the following behavior: all the time the
> users are routed in the first thread using the MHD's event-driven,
> however, when someone executes some reporting generation -- blocking the
> server --, each new request MHD checks if the route is still blocked, if
> so, MHD creates a new thread (also in event-drive way) redirecting the
> next request for it.
> 
> I don't know if I was clear in my explanation, but in short I'm trying
> something like the nginx's "Least Connected", however using purely MHD
> requests.
> 
> --
> Silvio Clécio