On Jan 30, 2008 5:03 AM, Afkham Azeez <[EMAIL PROTECTED]> wrote: > Locking is going to make the system highly inefficient. There are not many > systems in production which do this. e.g. In Tomcat, the default behavior > is to fire & forget (ASYNC) mode of transmitting state info. In Axis2, we > support both SYNC_ACK & ASYNC depending on the level of accuracy you need > and the response time. The replication takes just a few milliseconds. In > caching & throttling, I believe we only replicate the changes and not the > entire map, in which case most of these complications will not exist.
Agree with Azeez. During the f2f we discussed the option of locking and we decided against it for the reasons stated above. As long as we communicate clearly (Ruwans email indicates we have done that) to the users that there is a limitation then it is fine. Rajith. > > > Azeez > > > On Wed, Jan 30, 2008 at 12:35 AM, Rajith Attapattu <[EMAIL PROTECTED]> > wrote: > > > > > > > On Jan 29, 2008 1:13 PM, Ruwan Linton <[EMAIL PROTECTED]> wrote: > > > > > Rajith, > > > > > > > > > > > > > > > > Most part of synapse is stateless and hence does not have any > > > > > effect over clustering, but Caching and Throttling does. So Caching > > > > > and > > > > > Throttle mediators use the axis2-clustering implementation to > > > > > replicate the > > > > > state of those mediators among the cluster within the implementation > > > > > of > > > > > those mediators it self. Other than that we do not replicate states of > > > > > synapse in a global scope. I think this model fits for the moment and > > > > > has > > > > > performance improvements over supporting clustering in a global scope. > > > > > > > > > > > > > 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. > > > > thanks, > > > > Rajith Attapattu > > Red Hat > > blog: http://rajith.2rlabs.com/ > > > > > > > Or else to replicate the whole context hierarchy you could use > > > Replicator.replicate(); as well. One has to decide the proper method > > > and when to use which by evaluating the complexity and performance of the > > > implementation .... > > > > > > Thanks, > > > Ruwan > > > > > > -- > > > Ruwan Linton > > > http://www.wso2.org - "Oxygenating the Web Services Platform" > > > > > > > > > > > > -- > Thanks > Afkham Azeez > > http://azeez78.blogspot.com > http://www.wso2.org > GPG Fingerprint: 643F C2AF EB78 F886 40C9 B2A2 4AE2 C887 665E 0760 -- Regards, Rajith Attapattu Red Hat blog: http://rajith.2rlabs.com/
