This enhancement request is based on our misunderstanding of Tomcat clustering. We were under the impression that we could use the "useDirtyFlag" attribute in conjunction with DeltaManager to cause session replication to occur after each request (vs only on certain requests that manipulate the session via Session.setAttribute, etc.) Apparently useDirtyFlag is not applicable to DeltaManager. In our scenario, this is problematic because we have a mutable object that is stored in the session and manipulated after a call to Session.getAttribute but not followed by a new call to Session.setAttribute. Because there is no setAttribute call, the session is not propagated. Our "fix" was to add a call to the internal version of DeltaSession.setAttribute (not notifying listeners) from within DeltaSession.getAttribute. If desired and with some direction, I could submit a patch that would make this behavior configurable.
This Tomcat 5 enhancement request has been moved to Tomcat 7 (the latest version) since Tomcat 5 development is limited and focussed on bugs and security issues whereas Tomcat 7 is still seeing new feature development.
I think a better way to implement this is via manager options that control calls to listeners when setAttribute() is called with the already bound value. As I looked into this I noticed some inconsistencies in the current behaviour. I've started a discussion in the dev list about how to handle this.
I've added the additional configuration option to Manager for 9.0.6 onwards. I don't propose back-porting these additions at this time.