Re: [jbosscache-dev] JBoss Cache weakness handling heuristic transaction outcomes - [Fwd: [Fwd: New case comment notification. Case Number 00017677]]

On 21 Aug 2007, at 15:44, Jonathan Halliday wrote: > Manik Surtani wrote: >> Sorry about the slow response on this. >> While making JBC an XA resource is on the roadmap, it isn't something >> scheduled for any imminent release [1], as this is a pretty big >> change for the JBC codebase (and more importantly, a big feature >> change which would involve a lot of compatibility testing). >> For the time being, treating STATUS_UNKNOWN as a rollback would help, >> but only provided the database (and any other resources participating >> in the tx) has rolled back as well. Jonathan, correct me if I am >> wrong, but there is no way to know this unless we are an XA resource >> as well, am I right? > > Actually in heuristic outcomes you still won't necessarily know what > the db did. The transaction manger will tell you what it decided, but > not what each individual resource actually did. For that you would > need JBossTS specific code rather than general XAResource code. You > can partially address that by making the cache the last resource but > you won't eliminate it entirely. > >> So is it reasonable to treat a STATUS_UNKNOWN as a rollback, and >> document this limitation, until JBCACHE-70? > > yes, or toss anything that is affected out of the cache and let it be > reread from the db on the next tx, which would prevent you ever > getting out of sync. Or course that assumes the data is backed by some > store e.g. the db, which is the case only for EJBs. General purpose > use of the cache is a more difficult case. Perhaps a switch for this behaviour? By default, do a rollback, unless -Dorg.jboss.cache.tx.heuristic_outcome_purge = true?

What do you guys think? Cheers, -- Manik Surtani Lead, JBoss Cache JBoss, a division of Red Hat