Hi Malte. Being able to establish persistent connections would enable nginx to 'reuse' them -- thus avoiding the (small) latency of TCP slow start for each connection. Of course the question that then arises in ones mind would be 'how many permanent connections to make'--a possible answer being either a fixed number per backend, or a dynamic pool (i.e. as many as you ever happen to need, reusing them as they are freed). It would be nice, for example, to be able to specify a certain number of maximum connections to each instance of Mongrel (running Ruby on Rails) at one, as only one can be processed at a time, and this would then guarantee load balancing between them.

The next step in this particular paradigm would be to have nginx specify and open a port on which backends can connect, themselves, and then have nginx automatically balance between all currently connected back ends. This would enable a user to create more mongrel instances (say on other machines) and attach them to nginx silently and without any down time.

In retrospect I think TCP slow start is not dramatically slow when on the same machine, and nginx already does some nice load balancing, but my suggestions might result in a minimal gain, but maybe a few milliseconds. Thoughts? Thanks. -Roger

On 9/17/07, Malte Sussdorff <suss...@public.gmane.org>
wrote: