My bad, bcos I initially sent it to the wrong list :(. Rajith
On Jan 30, 2008 4:30 AM, Asankha C. Perera <[EMAIL PROTECTED]> wrote: > Guys > > Please do not CC: mails to the old synapse-dev@ mailing list.. The dev@ > list now works fine and so you can all discontinue using the old lists.. :-) > > > thanks > asankha > > > Ruwan Linton wrote: > > Rajith, > > > > > > Yep I am in agreement. The reason I asked about clustering is bcos > > > > of the recent thread on session mgt and the need to have the > > > > session-mediator state replicated across the cluster (I hope I didn't > > > > misunderstand the requirments here). I was wondering if this sort of > > > > thing > > > > is trivial to implement. Like can we replicate any mediator state if we > > > > choose to in a trivial way? > > > > > > > > > > Yes it is, I think the session-mediator has to take the replication in > > > to account (i.e. another state full mediator for synapse :)). If you > > > are using the ConfigurationContext of axis2 (basically the whole context > > > hierarchy) to store the data (for example, the session data table mapped > > > using a session id) you just need to call ConfigurationContext.flush(); > > > to replicate any data which has been changed after the last replication. > > > Additionally if you need to just replicate some of the properties of the > > > cfgCtx then you can call the the flush method with the property names (see > > > the clustering API for the exact signature of the method, I don't remember > > > that exactly). > > > > > > > Ruwan, once again thank you for the detailed answer. I really appreciate > > it. The reason behind the question "can we replicate any mediator state if > > we choose to in a trivial way?" was to figure out if the current axis2 > > clustering support is sufficient. > > > > However we have to be careful when replicating mediator state especially > > when there are concurrent modifications on different nodes. This can cause > > undesired affects and it is a limitation in our current clustering > > implementation. So even for the session map, if two nodes modify the map > > concurrently we may have issues. This doc explains the limitations > > http://ws.apache.org/axis2/1_3/clustering-guide.html. > > So perhaps it's worthwhile to highlight these issues to synapse users > > who want to tap into the clustering support. > > > > Yes, we know this limitation is there. Even we have a JIRA for the > Throttle mediator [1]. This is because there is no distributed locking > mechanism in axis2-clustering implementation. But again we have not came > across any requirement to support that level of replication to happen from > users and most of them are fine with this error. > > [1] - https://issues.apache.org/jira/browse/SYNAPSE-180 > > Thanks, > Ruwan > > -- > Ruwan Linton > http://www.wso2.org - "Oxygenating the Web Services Platform" > > -- Regards, Rajith Attapattu Red Hat blog: http://rajith.2rlabs.com/
