Re: [infinispan-dev] [Cloudtm-discussion] CloudTM: Additional Atomic broadcast based replication mechanism integrated in Infinispan

On 4/17/11 7:55 PM, Manik Surtani wrote: > Excellent stuff, Paolo and Pedro. My comments below, inline. Cc'ing infinispan-dev as well. Thanks Manik! > On 16 Apr 2011, at 21:47, Paolo Romano wrote: > > ... > I presume this implementation still plays nice with XA/JTA? In that transactions marked for rollback, etc are respected? Kind of :) We didn't really polish the code to have it fully integrated with XA/JTA, but this could be done without too many problems. Basically, if Infinispan is the only resource in a distributed xact, and it is configured to work in replicated mode, then it could externalize a 1 phase commit interface. In this case, the output of the commit phase would be that of the AB-based certification, avoiding totally 2PC. If on the other hand, Infinispan (replicated) needs to be enlisted in a distributed transaction encompassing other resources, 2PC is unavoidable. In this case, when an (replicated) Infinispan node receives a prepare message from some external coordinator it could i) AB-cast the prepare message to the other replicas, and ii) do the lock acquisition and write-skew validation to determine the vote to be sent back to the external coordinator. (Note that all replicas are guaranteed to determine the same outcome here, given the total order guarantees of the ABcast and that the certification procedure is deterministic.) The write-back and lock release should instead be done upon receipt of the final decision (2nd phase of the 2PC) from the coordinator. Does this answer your question?