Re: Which scales better? J2EE, PHP, or CGIDEV2?

Den 07/10/10 20.46, Aaron Bartell skrev:

Here is some more documentation on Jetty Continuations. It appears as
though their work will be in a future version of the Servlet 3 spec.
http://docs.codehaus.org/display/JETTY/Continuations

I haven't followed Jetty closely after I found that we would go for the Java EE 6 Web Profile (plus they spent a LOT of time migrating to Eclipse).

I have, however, spent quite a bit looking at the Jetty source code (we had some special requirements) and it is extremely fluently written and easy to read, which gives me great confidence in the Jetty programmers and what other things they do.

I am not an expert at how Continuations are working, though I have
done some Servlet programming in my day. As I understand it there is
some sort of HTTPSession object that stores information enough to
marry up a client request with a server repository of meta-data about
that session. It would seem Continuations are solving a problem that
doesn't exist in the RPG + Apache/IBMi world (I don't feel like I can
call it RPG CGI anymore because that name doesn't really fit).

For example, we don't store multiple session threads but instead just
retain the previous request's "global" resources (i.e. global
variables in *PGM/*SRVPGM objects, open data paths, etc). Am I
reading that right? So it isn't like they are embarking on something
revolutionary and new - they are just fixing the error of their ways.
Somebody correct me if I am wrong.

As I understand it, it is a matter of being able to be able to "walk away" from the socket connection and come back later without having to drag a full TCP/IP object around, but my understanding is not deeper than that.

I frankly believe you cannot introduce this in _any_ without serious support from the language and runtime library. The C folks appear to be able to do it, but if you must keep your socket connection with you, you simply cannot scale as well as those who does not have to.

This is one of the reasons that it is hard writing an extremely well performing http-server :)