Transactions, aggregations, timeouts, file endpoint...

["Benckhuijsen, JF (Jeroen)" <je...@apg.nl>]

Hi,

I've got the following routes set-up:

Jpa --> aggregation (jdbc, with completion size & timeout) --> multicast to(direct1) & to (direct2)

Direct1 --> bean1 --> marshal(bindy) --> to(file:file1)
Direct2 --> bean2 --> velocity --> to(file: file2)

I.e. I aggregate messages from a JPA store, once enough of them are accumulated or a timeout has been reached, I route the aggregated messages to two endpoints, each of which generates a file. 

I've got a requirement to let this route behave transactional:
* JPA --> aggregation should be transactional: i.e. in case aggregation fails, the item in the JPA store should not be removed
* aggregation --> file1 & file 2 should be transactional: i.e. in case the generation of one of the two files fails, the aggregation should remain and the files should not be written (or deleted via compensations).

I've been fiddling around with transactions and compensations, trying to find answers on the internet and in the Camel inaction book,  but haven't really been able to get the whole thing working. The following questions are what currently bothers me:
* jpa -> aggregation is marked as transacted(). However it seems to me this implies the whole of all routes is transacted (i.e. in case of a failure, the rollback is to the JPA store, not to the aggregation). As the completion timeout may be quite large (e.g. 24 hours), wouldn't this cause a transaction timeout to occur? I've been looking into a second transaction (with REQUIERES_NEW) after the aggregation. Is this the correct way to split the transactions?
* Compensations: although the transaction fails, the onSucces of the Synchronization is called, which to me seems weird.
* In case an error occurs, maintenance personnel would like to receive an email with the error so corrective actions can be taken. I've tried with both the onException() and errorHandler, but both don't seem to do what I want (the message is not delivered, at least, in the case where I used a direct endpoint as a first test case).

Thanks for any help.

Jeroen
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