"Update Narayana to dump a lot of data when the transaction fails. Same as the Byteman approach, but will be useful for more users."
Yes, but what about the performance impact on the rest of the system and users when this happens? Furthermore, define "fails" because if the application has told the transaction to rollback then the information needed is different to if the reaper forces it to rollback, for instance. Plus, maintaining data for all transactions throughout their life just so that it can be dumped out in the small case that the transaction rolls back seems of dubious benefit to the 99.99% of users who don't have failing transactions.