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

[Thorbjoern Ravn Andersen <ravn@xxxxxxxxxx>]

 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 :)