is it possible to connect to memcached and check in access phase?

[Huy Phan]

Is the DNS resolver module available on nginx so that I can check ?
The main point of my workflow is that everything should be done at access 
phase, so asynchornous is useless in this case isn't it ?

When you said memcached client, doesn't it mean doing self-coding network 
programming inside nginx ? I still prefer using the code done by nginx to 
prevent risks if there's any.