Choosing not to save @session in a given controller or actio

Hi !

All is in subject. In fact Â? but I may make things wrong Â? since IÂ?ve
deployed my rails app on an Apache/FastCGI with 3 ruby processes I
encounter
a problem.

In my application, an applet requests a lot of thumbnails to the
webserver.
Serving these thumbnails need to read some variables in my @session.

My problem occurs when, in my website (the one which contains the
applet) I
decide to change the content of my applet. I make another request to the
webserver. This one is served by another of the two remaining instances
of
ruby; and writes some (important, of course) values in @session. But the
other instance of ruby was in the middle of the action that return a
given
thumbnail. So when it ends, it writes the @session as it read it at its
beginning (with no modification since it doesnÂ?t make any). So the
@session
variable is totally broken for my next calls to Â?get_thumbnailÂ? because
the
@session modification that I thougt I made has been overwritten Â?Â?Â?

Does anybody know if (except if my design is really a bad idea ? Â? i.e.
using @session that way) itÂ?s possible, to tell a controller or an
action
not to Â?close_sessionÂ? at its end ? (but of course I donÂ?t want to
totally
disable session for that controller/action, because I need to read
@sessionÂ?)

Thanks in advance,

Benjamin (from France :op)