Of all the many things affecting performance in Servlets, the session mechanism is probably the least important.
I think the specifics of the in-memory mechanism itself aren't very important, but
being aware of the volume/frequency of session updates by the application is critical for scalability.
It is especially important for a cluster, where agressive session persistance settings in the container config may cause modifcations to the session to persist directly to a datasource.
These concerns are probably more architectural than impementation, but everyone along the way should be aware.
JMHO,
Chris
[ April 06, 2003: Message edited by: Christopher Dixon ]
[ April 06, 2003: Message edited by: Christopher Dixon ]