Gianni, What you have done is very cool. I guess my only comment is that what I am reading is that the annotations force a lock to the clustering engine, as opposed to being somewhat transparent by swapping out the clustering manager.
Therefore, my application code needs these annotations coded as a part of it. In otherwords, in order for me to leverage the fine grained capabilities of WADI, my application needs to be coded with the WADI annotations. Did I read that correctly? Regardless...its pretty cool stuff. We should talk about the contract/interface for openejb...I look forward to working with you ;-) Jeff Gianny Damour wrote: > On 17/10/2007, at 11:53 PM, Jeff Genender wrote: > >> >> >> Gianny Damour wrote: >>> >>> Excerpt of the conclusion: >>> >>> " >>> The effectiveness of the design and implementation of WADI's distributed >>> session lookup engine and replication engine is further comforted by the >>> observed average response times and scalability characteristics. >>> For the considered scenarios, WADI performs better than Terracotta, >>> which is not really surprising as... >>> >> >> If I may comment here...Without fine-grained clustering capabilities, I >> have a hard time believing that WADI can outperform Terracotta. >> Especially with large objects...WADI would push over the entire object >> each time, where Terracotta would only ship the changed members. If you >> are going to publish the numbers you did, you probably should explain >> what is getting pushed across. > > Hi, > > I believe you simply skimmed through what I have been writing: firstly, > I did provide a description of the state stored in session. Secondly, > your comment about large objects and the inadequacy of WADI's design to > handle them is clearly and explicitly discussed in the second paragraph > of the conclusion. As redundancy of information is not much of a problem > for theoretical clustering discussions, I am reiterating: WADI does > provide a fine grained replication mechanism, which is able to track > field updates or method executions and replay them against replicas. If > you are interested by this kind of stuff, then please feel free to have > a look to this WIKI page - > http://docs.codehaus.org/display/WADI/5.+Delta+Session+Replication. > > At this stage, the delta replication stuff is under performing and > resource intensive: to give you an idea, its average response time is > 6.10ms for the third test scenario (average response time for default > replication mechanism is 4.77ms for WADI and 6.36ms for Terracotta). > Once again, as a preliminary comment to Ari's response, this is a > scenario with HTTP session stickiness on. After this week-end, the > performance for fine-grained replication should improve significantly. I > intend to: get ride of native reflection; index constructor, field and > methods description for really fast packaging on wire and resolution > when reading back from a byte stream; and re-use reflective invokers > (CGLIB FastMethod/Constructor and ASM customed field updaters). > > FWIW, I do not see support of large objects as crucial as you for Web > solutions. Even if I spent a couple of months working on wadi-aop to > provide this feature, it was more with the ultimate goal to leverage it > for efficient distributed caching than HTTP session replication. I truly > believe that large scale Web solutions requiring HA have to be designed > with this constraint in mind; with this constraint in mind, keeping > session size small sounds reasonable. > > >>> " >>> >>> If people are interested by clustering development, then please respond >>> as I will resume some Geronimo clustering work and could really use a >>> hand. >>> >> >> I am in the midst of getting OpenEJB clusterable. I would be happy to >> combine forces and get clustering finished up for G ;-) > > Great! Will post back to the dev@ list as soon as I resume Geronimo > clustering work. > > Thanks, > Gianny > > > >> >>> Thanks, >>> Gianny
