Re: [dna-dev] Non-XA compliant resource participation in distributed transactions

Right. Now I guess I have a question, tho, regarding the implementation of federation connectors to systems (e.g., file systems in particular) that don't have any natural support for transactions. Is implementing the connector as if it is XA- compliant a bad thing to do? On May 15, 2008, at 3:59 AM, Mark Little wrote: > As I said in an earlier email, there are significant differences > between compensating transactions and ACID transactions (of which > XA is just one possible implementation). You shouldn't offer > compensating transactions opaquely to users if they register > multiple 1PC-aware resources because the semantics are different. > Using them without understanding the implications can be a PITA at > best and cause significant data inconsistencies at worse > (compensations can fail or take an arbitrary amount of time to > resolve). ACID transactions are a pretty good default. If users > have multiple 1PC-aware resources then it may be in their best > interests to convert them to 2PC rather than be lulled into some > false sense of security that somehow a compensating transaction > will give them the same guarantees. > > Mark. > > > > On 14 May 2008, at 22:28, Randall Hauch wrote: > >> I agree that what you are suggesting is still transactional >> (except for the last source, which is not transactional). But we >> will likely need to supporting several non-XA sources (e.g., file >> systems, applications, etc.) within an XA system. And, if we know >> the individual changes to each node for each source, we shouldn't >> we also be able to use compensating transactions to "rollback" >> changes to the non-XA system? >> >> I think there's value to supporting both. I just think the odds >> of having more than one non-XA source is pretty high. >> >> On May 14, 2008, at 4:22 PM, John P. A. Verhaeg wrote: >> >>> The big difference here seems to be the exposure of the updates >>> before the distributed transaction is committed. What I'm >>> suggesting is still XA-compliant, while compensating transactions >>> are not. >>> >>> Randall Hauch wrote: >>>> This is the behavior allowed by JBoss Transactions (Arjuna), and >>>> it seems useful. However, I wonder if we can do compensating >>>> transactions, is there still an advantage to supporting n-1 XA >>>> plus 1 non-XA? >>>> >>>> Cheers, >>>> >>>> Randall >>>> >>>> On May 14, 2008, at 4:10 PM, John P. A. Verhaeg wrote: >>>> >>>>> Seems like we ought to strive to support n-1 XA resources for >>>>> distributed transactions, allowing for the last participant in >>>>> a transaction (thus, this participants updates can't be done in >>>>> parallel with the other resources) to not support XA >>>>> transactions, but still participate in a distributed >>>>> transaction with other XA-compliant resources. Unlike >>>>> compensating transactions, the non-XA participant would appear >>>>> transactional and none of the updates would be visible until >>>>> the entire transaction was complete. It seems like this could >>>>> open up many more possible configurations for customers. >>>>> _______________________________________________ >>>>> dna-dev mailing list >>>>> dna-dev(a)lists.jboss.org >>>>> https://lists.jboss.org/mailman/listinfo/dna-dev >>>> >>>> >>> _______________________________________________ >>> dna-dev mailing list >>> dna-dev(a)lists.jboss.org >>> https://lists.jboss.org/mailman/listinfo/dna-dev >> >> _______________________________________________ >> dna-dev mailing list >> dna-dev(a)lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/dna-dev > > ---- > Mark Little > mlittle(a)redhat.com > > JBoss, a Division of Red Hat > Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod > Street, Windsor, Berkshire, SI4 1TE, United Kingdom. > Registered in UK and Wales under Company Registration No. 3798903 > Directors: Michael Cunningham (USA), Charlie Peters (USA), Matt > Parsons (USA) and Brendan Lane (Ireland). >